{"id":11057,"date":"2026-11-11T13:18:59","date_gmt":"2026-11-11T12:18:59","guid":{"rendered":"https:\/\/blueportance.com\/knowledge-base\/seat-cushion-comparison\/"},"modified":"2026-11-12T12:30:35","modified_gmt":"2026-11-12T11:30:35","slug":"seat-cushion-comparison","status":"publish","type":"page","link":"https:\/\/blueportance.com\/en\/knowledge-base\/seat-cushion-comparison\/","title":{"rendered":"CDC_Guide comparatif_Seat cushion comparison: what do they allow the body to do?"},"content":{"rendered":"\n<style>\n.bp-grille-sbnfa{font-family:Georgia,serif;max-width:860px;margin:24px auto;color:#1c2b39;line-height:1.55}\n.bp-grille-sbnfa h1{color:#0b3d6b;font-size:1.7em;line-height:1.25}\n.bp-grille-sbnfa h2{color:#0b3d6b;border-bottom:2px solid #0b3d6b;padding-bottom:4px;margin-top:36px}\n.bp-grille-sbnfa h3{color:#0b3d6b;margin-top:26px}\n.bp-grille-sbnfa h4{margin:16px 0 6px;color:#24486b}\n.bp-grille-sbnfa .bp-meta{color:#667;font-size:.9em}\n.bp-grille-sbnfa .bp-lead{font-size:1.12em}\n.bp-grille-sbnfa table{border-collapse:collapse;width:100%;margin:8px 0;font-size:.95em;table-layout:fixed}\n.bp-grille-sbnfa caption{text-align:left;font-size:.85em;color:#556;padding-bottom:4px}\n.bp-grille-sbnfa td,.bp-grille-sbnfa th{border:1px solid #c8d3de;padding:6px 8px;vertical-align:top}\n.bp-grille-sbnfa th{background:#e8eef4;text-align:left}\n.bp-grille-sbnfa .bp-gradation th:first-child,.bp-grille-sbnfa .bp-gradation td:first-child,.bp-grille-sbnfa .bp-correspondance th:first-child,.bp-grille-sbnfa .bp-correspondance td:first-child{width:64px;text-align:center}\n.bp-grille-sbnfa .bp-entree tr.bp-fam th{background:#0b3d6b;color:#fff}\n.bp-grille-sbnfa .bp-sources-table td:first-child{width:46%;font-size:.88em}\n.bp-grille-sbnfa .bp-sources-table td:nth-child(2){width:17%;font-size:.88em}\n.bp-grille-sbnfa .bp-sources-table td:nth-child(3){font-size:.92em}\n.bp-grille-sbnfa .bp-fiche{border-top:1px solid #dde4ea;margin-top:22px}\n.bp-grille-sbnfa .bp-observe{font-size:.93em;background:#f7f7f2;border-left:3px solid #b9b08a;padding:8px 12px}\n.bp-grille-sbnfa .bp-aporia{background:#f1f6fb;border-left:3px solid #0b3d6b;padding:8px 12px}\n.bp-grille-sbnfa .bp-familles{color:#667}\n.bp-grille-sbnfa .bp-ok{color:#2a7a2a;font-weight:bold;font-size:1.2em}\n.bp-grille-sbnfa .bp-fr{font-size:.82em;color:#556}\n.bp-grille-sbnfa .bp-src{text-align:left;margin-top:6px;font-size:.82em}\n.bp-grille-sbnfa .bp-src summary{cursor:pointer;color:#0b3d6b;font-weight:bold}\n.bp-grille-sbnfa .bp-src ul{padding-left:16px;margin:6px 0}\n.bp-grille-sbnfa .bp-src li{margin-bottom:6px}\n.bp-grille-sbnfa .bp-srcl{color:#556}\n.bp-grille-sbnfa .bp-synth td{text-align:left!important}\n.bp-grille-sbnfa .bp-stars{color:#d08a00;font-size:1.1em;white-space:nowrap}\n.bp-grille-sbnfa .bp-num{font-size:.75em;color:#556}\n.bp-grille-sbnfa .bp-com{font-size:.84em;color:#445}\n.bp-grille-sbnfa .bp-var{font-size:.85em;color:#667}\n.bp-grille-sbnfa .bp-scroll{overflow-x:auto}\n.bp-grille-sbnfa .bp-synth tr.bp-fam th{background:#0b3d6b;color:#fff}\n.bp-grille-sbnfa .bp-synth td:not(:first-child){text-align:center}\n.bp-grille-sbnfa .bp-ex td{font-size:.82em;color:#556}\n.bp-grille-sbnfa .bp-fam-niv td:first-child{width:40%}\n.bp-grille-sbnfa .bp-renvoi{font-size:.85em}\n.bp-grille-sbnfa .bp-origine{border:1px solid #c8d3de;padding:8px 12px}\n.bp-grille-sbnfa .bp-synthese{background:#f4f7fa;padding:10px 12px}\n.bp-grille-sbnfa .bp-sbnfa,.bp-grille-sbnfa .bp-voir{font-size:.9em;color:#445}\n.bp-grille-sbnfa .bp-attribution{margin-top:36px;font-size:.88em;color:#556;border-top:1px solid #ccc;padding-top:12px}\n<\/style>\n<article class=\"bp-grille-sbnfa\" lang=\"en\">\n<header><h1>Seat cushion comparison: what do they allow the body to do?<\/h1>\n<p class=\"bp-meta\">Blue Portance guide \u00b7 SBNFA\u2122 framework \u00b7 version 23 of November 12, 2026<\/p><\/header>\n<style>\n.bp-grille-sbnfa .bp-partie{margin:2.6rem 0 1rem;padding:.7rem 1rem;background:#0055A4;color:#fff;border-radius:8px}\n.bp-grille-sbnfa .bp-partie p{margin:0;color:#fff}\n.bp-grille-sbnfa .bp-partie .bp-partie-n{font-size:.8rem;letter-spacing:.08em;text-transform:uppercase;opacity:.85}\n.bp-grille-sbnfa .bp-partie .bp-partie-t{font-size:1.25rem;font-weight:700;line-height:1.3}\n.bp-grille-sbnfa .bp-encadre{margin:1.2rem 0;padding:1rem 1.2rem;background:#f2f7fc;border-left:4px solid #0055A4;border-radius:8px}\n.bp-grille-sbnfa .bp-encadre>p:first-child{margin-top:0;font-weight:700;color:#0055A4}\n.bp-grille-sbnfa .bp-encadre ul{margin-bottom:0}\n.bp-grille-sbnfa .bp-sommaire ol>li>a.bp-som-partie{font-weight:700}\n.bp-grille-sbnfa .bp-suite{font-weight:700}\n<\/style>\n<div class=\"bp-partie\" id=\"partie-a\" role=\"note\"><p class=\"bp-partie-n\">Part A<\/p><p class=\"bp-partie-t\">What this guide is about<\/p><\/div>\n<p class=\"bp-lead\"><strong>This comparison does not only look at what a cushion is made of: it examines what it allows the body to do.<\/strong><\/p>\n<aside class=\"bp-encadre\" id=\"decision\"><p>Quick decision<\/p><ul>\n<li><strong>Tailbone pain:<\/strong> a coccyx cushion with a rear cutout takes the tailbone off the seat; it leaves the pelvis little mobility and imposes its own orientation.<\/li>\n<li><strong>Perineal pain or pudendal neuralgia:<\/strong> a cushion with a central perineal cutout frees the perineum; it locks the seat into a single balanced position.<\/li>\n<li><strong>Donut cushion:<\/strong> it frees the center, but the load shifts to the ring, which still bears on the sacrococcygeal region.<\/li>\n<li><strong>Prolonged sitting, pain that returns when you move, or a pelvis that feels locked:<\/strong> a cushion with independent supports (APORIA\u00ae) combines offloading of the painful zone with pelvic mobility.<\/li>\n<\/ul><p style=\"margin-bottom:0;font-weight:400;color:inherit\">The details are in the <a href=\"#tableau\">comparison table<\/a> (Part B) and, attribute by attribute, in the <a href=\"#partie-c\">detailed analysis<\/a> (Part C). This guide does not replace the advice of a health professional.<\/p><\/aside>\n\n<nav class=\"bp-sommaire\" aria-label=\"Contents\"><p><strong>Contents<\/strong><\/p><ol><li><a class=\"bp-som-partie\" href=\"#partie-a\">Part A \u2014 What this guide is about<\/a><ul><li><a href=\"#decision\">Quick decision<\/a><\/li><li><a href=\"#choisir\">Which cushion should you choose when sitting hurts?<\/a><\/li><\/ul><\/li><li><a class=\"bp-som-partie\" href=\"#partie-b\">Part B \u2014 The comparison table<\/a><ul><li><a href=\"#lequel-choisir\">Coccyx cushion, donut, or perineal cushion: which one should you choose?<\/a><\/li><\/ul><\/li><li><a class=\"bp-som-partie\" href=\"#partie-c\">Part C \u2014 The detailed analysis, attribute by attribute<\/a><ol><li><a href=\"#decharge\">Does pressure offloading really bring relief when sitting?<\/a><ul><li><a href=\"#pourquoi-decharge\">Why does offloading bring relief?<\/a><\/li><li><a href=\"#a1\">How does a cushion take the tailbone or the perineum off the seat?<\/a><\/li><li><a href=\"#decharge-suffit\">Is offloading enough to relieve the pain?<\/a><\/li><li><a href=\"#douleur-revient\">Why does the pain persist or come back despite a cushion with a hole?<\/a><\/li><li><a href=\"#coccyx-sans-bloquer\">Which cushion offloads the tailbone without locking the pelvis?<\/a><\/li><li><a href=\"#perinee-sans-imposer\">Which cushion offloads the perineum without imposing a position?<\/a><\/li><\/ul><\/li><li><a href=\"#inconfortable\">Why does a cushion bring relief at first and then become uncomfortable?<\/a><ul><li><a href=\"#a2\">Why do my buttocks hurt after sitting for a long time?<\/a> <span class=\"bp-fr\">(A2)<\/span><\/li><li><a href=\"#a3\">Why does the pain come back when I move?<\/a> <span class=\"bp-fr\">(A3)<\/span><\/li><li><a href=\"#a4\">Why is sitting for a long time tiring?<\/a> <span class=\"bp-fr\">(A4)<\/span><\/li><li><a href=\"#b3\">Why do I feel pulling when I turn?<\/a> <span class=\"bp-fr\">(B3)<\/span><\/li><\/ul><\/li><li><a href=\"#rester-assis\">Which cushion should you choose to sit for a long time without pain?<\/a><ul><li><a href=\"#b1\">Why doesn&#8217;t my cushion follow my small movements?<\/a> <span class=\"bp-fr\">(B1)<\/span><\/li><li><a href=\"#b2\">Why do I feel locked when I sit?<\/a> <span class=\"bp-fr\">(B2)<\/span><\/li><li><a href=\"#c1\">Why do I find it hard to sit upright without getting tired?<\/a> <span class=\"bp-fr\">(C1)<\/span><\/li><li><a href=\"#c2\">Why does my pelvis feel locked?<\/a> <span class=\"bp-fr\">(C2)<\/span><\/li><li><a href=\"#c3\">Why does my lower back hurt when I sit?<\/a> <span class=\"bp-fr\">(C3)<\/span><\/li><li><a href=\"#c4\">Which cushion suits my arched or flat back?<\/a> <span class=\"bp-fr\">(C4)<\/span><\/li><\/ul><\/li><\/ol><\/li><li><a class=\"bp-som-partie\" href=\"#partie-d\">Part D \u2014 Method, reliability, and evidence<\/a><ul><li><a href=\"#fiable\">Is this comparison reliable? Method, sources, and limitations<\/a><\/li><li><a href=\"#cotations\">What are the ratings based on?<\/a><\/li><li><a href=\"#preuves-usage\">What does real-world use of APORIA\u00ae show?<\/a><\/li><li><a href=\"#methode\">Detailed method and sources<\/a><\/li><\/ul><\/li><\/ol><\/nav>\n<section id=\"choisir\"><h2>Which cushion should you choose when sitting hurts?<\/h2>\n<p>If your tailbone, perineum, lower back, or buttocks hurt when you sit, the right cushion does not depend only on its material, its shape, or its price. Above all, it depends on what the seat allows your body to do: take a sensitive zone off the seat, distribute pressure, follow your movements, and let you adjust without effort.<\/p>\n<p>Many cushions bring relief at first because they reduce the load on a painful zone. But the pain can come back when you move, when the foam sags, or when the pelvis can no longer move freely. That is why this guide does not only ask whether a cushion is soft or has a cutout. It also asks what it allows when you lean forward, turn, or try to regain your balance.<\/p>\n<p>We call this the <strong>adaptability potential<\/strong>: the capacity of a seat to allow the body to adjust, move, and maintain a functional balance without imposing a single position on it. This guide compares the main cushion families according to this capacity, attribute by attribute.<\/p>\n<p>The possibilities a person has to adjust their position, movements, supports, and stability, in particular to ease their pain, make up their <strong>adaptive reserve<\/strong>. The seat does not create this reserve: depending on its architecture, it can allow, limit, or constrain its expression.<\/p>\n<p>The guide is organized in four parts: after this introduction, the <a href=\"#tableau\">comparison table<\/a> (Part B) lets you choose quickly between a coccyx cushion, a donut, a perineal cushion, or a cushion with independent supports; the <a href=\"#partie-c\">detailed analysis<\/a> (Part C) explains each criterion, attribute by attribute, with its sources; Part D presents the <a href=\"#partie-d\">method, the limitations of the comparison, and the evidence from use<\/a>.<\/p>\n<p>APORIA\u00ae has been the subject of a user satisfaction study at Nantes University Hospital (CHU de Nantes); it is used in spinal rehabilitation, and 85% of people who try it for 30 days keep it. In the words of a pain physician, \u201cit is not yet another cushion or ring to sit on, but a product I would describe as an ergo-dynamic seat.\u201d <a href=\"#preuves-usage\">What real-world use shows<\/a>.<\/p>\n<p>This guide does not replace the advice of a health professional. It aims to help you understand what each type of cushion can, or cannot, allow your body to do.<\/p><\/section>\n<div class=\"bp-partie\" id=\"partie-b\" role=\"note\"><p class=\"bp-partie-n\">Part B<\/p><p class=\"bp-partie-t\">The comparison table<\/p><\/div>\n<section id=\"lequel-choisir\"><h2>Coccyx cushion, donut, or perineal cushion: which one should you choose?<\/h2>\n<p class=\"bp-direct\">A coccyx cushion with a rear cutout aims to offload the tailbone. A donut cushion frees the center but can concentrate pressure around its rim. A perineal cushion frees the central zone and may be suitable for perineal pain or pudendal neuralgia. The choice depends above all on the zone to protect and on how the cushion follows your movements.<\/p>\n<\/section>\n<section id=\"tableau\"><p>For each of the eleven attributes of <strong>adaptability potential<\/strong>, the table shows the level that each family&#8217;s architecture makes available to the person, from 1 to 4. Under each level, open \u201cFeedback and sources\u201d to read user and professional feedback and the documents that support it. The brands cited are examples; the rating applies to the family&#8217;s typical architecture.<\/p>\n<div class=\"bp-scroll\"><table class=\"bp-synth\"><caption><strong>Adaptability potential<\/strong>: level reached by each family, attribute by attribute<\/caption><thead><tr><th scope=\"col\">Attribute and function sought<\/th><th scope=\"col\">Solid coccyx cushion with U- or V-cutout<br><span class=\"bp-var\">with or without a sloped surface (wedge)<\/span><\/th><th scope=\"col\">Donut cushion (ring)<br><span class=\"bp-var\">foam, air, or gel<\/span><\/th><th scope=\"col\">Cushion with central perineal cutout<br><span class=\"bp-var\">hole, channel, or double opening<\/span><\/th><th scope=\"col\">Cushion with independent supports<br><span class=\"bp-var\">APORIA\u00ae: mobile base and four articulated supports<\/span><\/th><\/tr><\/thead><tbody>\n<tr class=\"bp-fam\"><th colspan=\"5\" scope=\"rowgroup\">A. Pressure<\/th><\/tr>\n<tr><td><a href=\"#a1\"><strong>A1. Offloading of the painful zone<\/strong><\/a><br><span class=\"bp-fr\">Is the painful zone taken off the seat, and is the offloading suited to that zone?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Cut-out zone: tailbone (rear cutout). The tailbone is out of contact; the perineum remains loaded. Rear offloading of the tailbone and the sacrococcygeal region, suited to pain located in this zone.<\/div><details class=\"bp-src\"><summary>Feedback and sources (4)<\/summary><ul><li><q>The mechanism is simple: the opening lets the coccyx float in free air rather than bear any body weight.<\/q><br><span class=\"bp-srcl\">Flexi Chair, Best Coccyx Cushions 2026 \u2014 <a href=\"https:\/\/flexi-chair.com\/accessories\/best-coccyx-cushions-tailbone-pain-2026\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>U-cutout: the tailbone stays free, weight is shifted onto the sit bones.<\/q><br><span class=\"bp-srcl\">Orthexa, coccyx cushion \u2014 <a href=\"https:\/\/orthexa.fr\/coussin-coccyx-pour-soulager-la-douleur-assise\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Foye 2009 study (Rutgers, 55 patients with coccydynia): those who state a preference choose the beveled cutout cushion almost 5 times more often than the donut; 42% prefer neither (preference, not efficacy).<\/q><br><span class=\"bp-srcl\">Live Hearth Well, reporting the Foye 2009 abstract \u2014 <a href=\"https:\/\/livehearthwell.com\/en\/guides\/coccyx-cushion-guide\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Study<\/em><\/span><\/li><li><q>The trade-off is that the tailbone is not fully unloaded. For acute, sharp tenderness, a partial cutout can still be too much contact.<\/q><br><span class=\"bp-srcl\">Grabberstool, Donut vs Wedge \u2014 <a href=\"https:\/\/grabberstool.com\/blogs\/news\/donut-cushion-vs-wedge-cushion-tailbone\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Cut-out zone: center (ring). The central zone is out of contact; the load shifts to the ring. Continuous rim at the back: the ring still bears on the sacrococcygeal region.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>Check that the opening is positioned correctly to avoid a misplaced pressure ridge.<\/q><br><span class=\"bp-srcl\">Orvimed, SYSTAM donut cushion product sheet \u2014 <a href=\"https:\/\/www.orvimed.fr\/maintien-a-domicile\/54-coussin-de-positionnement-bouee.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>The rear part of the ring can press on the tailbone or the lower sacrum.<\/q><br><span class=\"bp-srcl\">Orthoptimal, shapes and selection criteria \u2014 <a href=\"https:\/\/orthoptimal.fr\/blogs\/ortho-conseils-le-blog\/coussin-orthopedique-fessier-lequel-choisir-en-cas-de-douleur-au-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>If the targeted area makes contact, the pillow is incorrectly sized, positioned, or too soft for your body weight.<\/q><br><span class=\"bp-srcl\">Biology Insights, How to Sit on a Donut Pillow \u2014 <a href=\"https:\/\/biologyinsights.com\/how-to-sit-on-a-donut-pillow-for-maximum-relief\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>General-audience article<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Cut-out zone: perineum, often tailbone. The perineum, and often the tailbone, are out of contact. Offloading suited to perineal pain.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>A wedge or seat cushion with a front-to-back channel or cutout tends to work best, because it offloads the entire midline from the tailbone through the perineum while your weight rests on the thighs and sit bones.<\/q><br><span class=\"bp-srcl\">Dr. R. Naples (urologist), How to Sit With Pudendal Neuralgia \u2014 <a href=\"https:\/\/www.drrnaples.com\/how-to-sit-with-pudendal-neuralgia\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><li><q>Relieve pressure on sacrum and perineum, including the Alcock&#x27;s canal where the pudendal nerve is located. [\u2026] provides relief to the entire area from the sacrum to the perineum.<\/q><br><span class=\"bp-srcl\">Ergotech, Alcock Rest product sheet \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>The very best. Without this cushion, the mechanical pressure on the pudendal nerve when sitting is so intense that I cannot sit down without feeling pain. I have been using it for 2 years.<\/q><br><span class=\"bp-srcl\">J\u00e9r\u00e9my H., verified customer review, Alcock Rest (5\u2605) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Review hosted by the seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Cut-out zone depending on the version: perineum, tailbone, full channel. The offloading is formed by the space between the mobile supports.<\/div><details class=\"bp-src\"><summary>Feedback and sources (4)<\/summary><ul><li><q>The painful zones are freed from load.<\/q><br><span class=\"bp-srcl\">Dr. Anne Lassaux, pain physician, head of the Pain Assessment and Treatment department, Rothschild Hospital AP-HP until the end of June 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/shared-experiences\/aporia-reviews-dynamic-seating\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Pain physician, no declared conflict of interest<\/em><\/span><\/li><li><q>Regarding pain relief, the APORIA N\u00b01 seat seems to relieve cluneal and pudendal pain, and the APORIA N\u00b02 seat, for its part, seems to relieve tailbone pain.<\/q><br><span class=\"bp-srcl\">User satisfaction study, pelvic pain unit of CHU de Nantes, Dr. Am\u00e9lie Seneau L\u00e9vesque, report of December 13, 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/sitting-related-pain\/pelvi-seat-study-chu-nantes\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Hospital study<\/em><\/span><\/li><li><q>Offloading formed by the space between the four supports: the painful zone is out of contact.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>6 cm central offloading: four supports on ball joints follow the small movements of the pelvis without locking it or throwing it off balance.<\/q><br><span class=\"bp-srcl\">Blue Portance, manufacturer&#8217;s position \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr><td><a href=\"#a2\"><strong>A2. Static pressure distribution<\/strong><\/a><br><span class=\"bp-fr\">At rest, is pressure uniform across the entire contact surface?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Memory foam molds to the contours.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Memory foam deforms under body heat and weight, then molds to the shape of the pelvis, which spreads the load over a larger surface.<\/q><br><span class=\"bp-srcl\">Orthexa \u2014 <a href=\"https:\/\/orthexa.fr\/coussin-coccyx-pour-soulager-la-douleur-assise\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Some users report that the cushion compresses over time, potentially reducing support.<\/q><br><span class=\"bp-srcl\">User reviews reported by Corner Office HQ \u2014 <a href=\"https:\/\/cornerofficehq.com\/best-coccyx-seat-cushions\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>User testimonial<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Sinking concentrates on the crown of the ring.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>A donut does not eliminate pressure. It moves the same pounds onto less area, on a delay.<\/q><br><span class=\"bp-srcl\">Aylio, Donut vs twin cutouts \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Over a long sit, the rim becomes the new pressure point.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Within a few days the memory foam compresses and becomes uncomfortable (customer feedback on flattening, especially above 100 kg).<\/q><br><span class=\"bp-srcl\">Customer reviews, The White Willow \u2014 <a href=\"https:\/\/thewhitewillow.in\/products\/sky-hr-foam-donut-shaped-seat-cushion-tailbone-and-lumber-support-firm\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>User testimonial<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Memory foam molds to the contours around the cutout.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Higher-density foam on the outside and softer foam in the center. This reduces pressure on the perineal area when sitting.<\/q><br><span class=\"bp-srcl\">Pelican Manufacturing, Pudendal Channel Cushion \u2014 <a href=\"https:\/\/pelicanmanufacturing.com\/product\/pudendal-channel-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Distributes pressure across thighs and buttocks, ideal for muscular sensitivity.<\/q><br><span class=\"bp-srcl\">Ergotech, comparison of Alcock Rest versions \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/smartblog\/307_comparison-pudendal-cushion.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Each of the 4 memory foam supports carries the load it receives.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>The foam \u201cpads\u201d adapt to different anatomies by adjusting individually.<\/q><br><span class=\"bp-srcl\">Dr. Anne Lassaux, pain physician, head of the Pain Assessment and Treatment department, Rothschild Hospital AP-HP until the end of June 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/shared-experiences\/aporia-reviews-dynamic-seating\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Pain physician, no declared conflict of interest<\/em><\/span><\/li><li><q>Four independent memory foam supports: each one receives and carries its share of the load.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Four supports on ball joints follow the small movements of the pelvis without locking it or throwing it off balance.<\/q><br><span class=\"bp-srcl\">Blue Portance, manufacturer&#8217;s position \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr><td><a href=\"#a3\"><strong>A3. Dynamic pressure distribution<\/strong><\/a><br><span class=\"bp-fr\">Does pressure stay uniform during movement?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">When you lean forward, the load concentrates; you have to reposition yourself.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Cutout placed behind the tailbone, without tilting the pelvis forward; non-slip base (criteria for stability during movement).<\/q><br><span class=\"bp-srcl\">Orthoptimal \u2014 <a href=\"https:\/\/orthoptimal.fr\/blogs\/ortho-conseils-le-blog\/coussin-orthopedique-fessier-lequel-choisir-en-cas-de-douleur-au-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">When you lean, the load shifts to one side of the ring.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>A ring puts a hole in the middle of your base of support, so you balance on the rim, and the ring tilts when you shift. Inflatable donuts add a second wobble, because air moves away from wherever you press.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Slouching shifts your weight backward, which can push the sensitive area against the rear rim of the cushion.<\/q><br><span class=\"bp-srcl\">Biology Insights \u2014 <a href=\"https:\/\/biologyinsights.com\/how-to-sit-on-a-donut-pillow-for-maximum-relief\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>General-audience article<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">When you lean forward, the load concentrates; you have to reposition yourself.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Small, frequent changes in position usually help more than trying to find one perfect way to sit.<\/q><br><span class=\"bp-srcl\">Dr. R. Naples \u2014 <a href=\"https:\/\/www.drrnaples.com\/how-to-sit-with-pudendal-neuralgia\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><li><q>The fluid pouches can also be detached and moved to adapt to your pressure points while sitting (HV fluid version: manual adjustment possible, but no automatic following of movement).<\/q><br><span class=\"bp-srcl\">Ergotech, Alcock Rest usage advice \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">The base follows the movement and each of the 4 articulated supports adapts to its load.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>Mobile base and four articulated supports: when you lean, each support adapts to the load it receives.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Average customer rating: 4.7\/5.<\/q><br><span class=\"bp-srcl\">Trustpilot, Blue Portance reviews \u2014 <a href=\"https:\/\/fr.trustpilot.com\/review\/blueportance.com\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Independent review platform<\/em><\/span><\/li><li><q>The multi-articulated structure adapts continuously to help the body regulate its center of mass.<\/q><br><span class=\"bp-srcl\">APORIA\u00ae doctrinal position [INTERNAL MODEL] \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr><td><a href=\"#a4\"><strong>A4. Load variability<\/strong><\/a><br><span class=\"bp-fr\">Does the load stay fixed and constant, or does it vary while sitting?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Fixed support, constant stress with little variation; memory foam brings some pressure variability with movement.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Prolonged use locks the pelvis in anteversion and the lumbar spine in extension, reducing the variability of postural tone.<\/q><br><span class=\"bp-srcl\">Clinique OPS (sloped versions) \u2014 <a href=\"https:\/\/www.cliniqueops.com\/pathologies-posturales\/coussin-postural-sur-mesure-blog-article-217-fr.htm\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Fixed support on the ring, constant stress with erratic variation due to the ring&#8217;s unstable load-bearing.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Tissue under sustained load compresses, and a narrow ring pressing into the underside of the thighs and the outer glutes carries your whole weight on that thin band of contact.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Fixed support, constant stress with little variation.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>One-piece cushion: the fluid pouches can be moved by hand from one session to the next, but while sitting the support stays fixed.<\/q><br><span class=\"bp-srcl\">Ergotech (reading of the product options) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">The multi-articulated structure adapts continuously to help the body regulate its center of mass; each support sees its pressure vary with the rhythm of movement.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>It also appears that the APORIA N\u00b01 and APORIA N\u00b02 seats offer greater comfort than the cushions or other products used by patients in everyday life.<\/q><br><span class=\"bp-srcl\">User satisfaction study, pelvic pain unit of CHU de Nantes, Dr. Am\u00e9lie Seneau L\u00e9vesque, report of December 13, 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/sitting-related-pain\/pelvi-seat-study-chu-nantes\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Hospital study<\/em><\/span><\/li><li><q>Base and articulated supports: the load moves continuously under each support, giving tissues phases of offloading.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Four supports on ball joints follow the small movements of the pelvis without locking it or throwing it off balance.<\/q><br><span class=\"bp-srcl\">Blue Portance \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr class=\"bp-fam\"><th colspan=\"5\" scope=\"rowgroup\">B. Movement and tissues<\/th><\/tr>\n<tr><td><a href=\"#b1\"><strong>B1. Micromovements and mechanotransduction<\/strong><\/a><br><span class=\"bp-fr\">Does the seat follow the body&#8217;s smallest spontaneous movements?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Static seat: fixed contact.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>After 5 minutes of sitting, are you already starting to move? Positions that change every 5 minutes (the industry&#8217;s own marketing documents the need to move).<\/q><br><span class=\"bp-srcl\">Sameo, product sheet \u2014 <a href=\"https:\/\/www.sameo.fr\/products\/coussin-orthopedique-coccyx-sameo\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Static seat: fixed contact.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Maintaining a neutral spinal alignment is necessary [\u2026] avoiding any tendency to slouch or lean heavily to one side: proper use requires moving as little as possible.<\/q><br><span class=\"bp-srcl\">Biology Insights \u2014 <a href=\"https:\/\/biologyinsights.com\/how-to-sit-on-a-donut-pillow-for-maximum-relief\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>General-audience article<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Static seat: fixed contact.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Cushion well suited to my body shape, relief when sitting.<\/q><br><span class=\"bp-srcl\">Daniele W., verified customer review, Alcock Rest (4\u2605) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Review hosted by the seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Dynamic seat: each of the 4 articulated supports responds to the slightest input to follow and support.<\/div><details class=\"bp-src\"><summary>Feedback and sources (4)<\/summary><ul><li><q>I sit down, but I am not static on a cushion [\u2026] I look for my position. What matters is that the cushion can respond to my demand, not to its own.<\/q><br><span class=\"bp-srcl\">Pierre Ivaldi, physiotherapist and osteopath, former managing director (30 years) of the Saint-Jean group&#8217;s post-acute care and functional rehabilitation center, originator of several foundations of the SBNFA\u2122 framework \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>There is fluidity in the movement, so you feel accompanied by the cushion, which is mobile.<\/q><br><span class=\"bp-srcl\">Physiotherapy trainee in lumbar rehabilitation, Back School, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer), Essentia stool fitted with the APORIA\u00ae seat \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>User testimonial<\/em><\/span><\/li><li><q>Four supports on ball joints: each one responds to the slightest input from the pelvis.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>\u201cThe P\u00e9rin\u00e9e cushion has allowed me to eat sitting down, do DIY, and above all regain my independence by being able to drive.\u201d<\/q><br><span class=\"bp-srcl\">B\u00e9atrice D., customer testimonial \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Testimonial hosted by Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr><td><a href=\"#b2\"><strong>B2. Three-dimensional pelvic mobility<\/strong><\/a><br><span class=\"bp-fr\">Can the pelvis move freely in all three planes around its balance point?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Forward-backward and lateral tilt remain possible. Free and independent rotation of the pelvis is impossible: the hips have no independent supports and the interface cannot follow the rotation.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Your pelvis tips forward. Your lower back curves inward rather than rounding outward.<\/q><br><span class=\"bp-srcl\">Ageproof, 3-week test of an 8\u00b0 wedge \u2014 <a href=\"https:\/\/www.ageproof.co.uk\/reviews\/devices\/sitting-wedge-review\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Product test<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Forward-backward and lateral tilts theoretically possible but, in practice, limited by the constraints of the ring&#8217;s geometry and the instability observed; the back is blocked by the rim.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>This configuration often causes the hips and pelvis to roll backward, forcing the lower back into a rounded, slumped position \u2014 a posterior pelvic tilt.<\/q><br><span class=\"bp-srcl\">Sit Cushion \u2014 <a href=\"https:\/\/sitcushion.com\/u-shape-coccyx-cushion-or-donut\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Donut pillows often force the user to slouch forward to balance on the front of the ring.<\/q><br><span class=\"bp-srcl\">Sit Cushion \u2014 <a href=\"https:\/\/sitcushion.com\/donut-pillows-vs-coccyx-cutouts-which-pressure-relief-cushion-is-right-for-you\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Forward-backward tilt remains possible. Lateral tilt is uncomfortable (weight shifted onto a small area). Free and independent rotation of the pelvis is impossible: the hips have no independent supports and the interface cannot follow the rotation.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Weight rests on the thighs and sit bones: the channel frees the midline, while the lateral support stays on a reduced surface.<\/q><br><span class=\"bp-srcl\">Dr. R. Naples \u2014 <a href=\"https:\/\/www.drrnaples.com\/how-to-sit-with-pudendal-neuralgia\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><li><q>Cushion thicker at the back than at the front: backward tilt is constrained by the geometry in any case.<\/q><br><span class=\"bp-srcl\">Ergotech, technical sheet (5 cm back \/ 2 cm front) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Mobility in all three planes, including forward-backward tilt. The four independent supports and the mobile base follow the rotation of the pelvis driven by the hips, with no mechanical return to a single position; the starting orientation is set according to the profile (see C4). Placed on a chair, the cushion follows rotation over 10\u00b0. <strong>Level 3, not 4<\/strong>: rotation is followed over a limited range.<\/div><details class=\"bp-src\"><summary>Feedback and sources (4)<\/summary><ul><li><q>It is about considering the individual in a three-dimensional space and not in a plane.<\/q><br><span class=\"bp-srcl\">Pierre Ivaldi, physiotherapist and osteopath, former managing director (30 years) of the Saint-Jean group&#8217;s post-acute care and functional rehabilitation center, originator of several foundations of the SBNFA\u2122 framework \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>On rotations, the double articulation will give us much better mobility.<\/q><br><span class=\"bp-srcl\">S\u00e9bastien Bottau, physiotherapist, head of the dedicated Spine Unit \/ Back School space, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer), Essentia stool fitted with the APORIA\u00ae seat \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>Curved base and four supports on ball joints: tilts in all three planes; rotation of 10\u00b0 in the horizontal plane followed when the cushion is placed on a chair.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Four supports on ball joints: decoupled left\/right mobility [APORIA\u00ae POSITION].<\/q><br><span class=\"bp-srcl\">Blue Portance \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr><td><a href=\"#b3\"><strong>B3. Protection against shear and pulling<\/strong><\/a><br><span class=\"bp-fr\">When the pelvis moves, does the seat follow the movement or resist it, causing pulling and shear?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">The one-piece cushion can resist movement; memory foam reduces shear.<br><b>Special case: level 3\/4 <span class='stars'>\u2605\u2605\u2605\u2606<\/span><\/b><br>Cushions with cells or pads that follow movement.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Foam that is too soft compresses completely and lets the tailbone touch the seat again, with no real benefit.<\/q><br><span class=\"bp-srcl\">Orthexa \u2014 <a href=\"https:\/\/orthexa.fr\/coussin-coccyx-pour-soulager-la-douleur-assise\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>A flat cushion with cutouts is structurally just a flat cushion. It stays where you put it: a stable but one-piece surface (it holds the skin during movement).<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">The edge effect of the crown increases pulling, a phenomenon known as the \u201cring problem.\u201d<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Concentration is not a side effect of the donut shape \u2014 it is the shape.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">The cushion with its central cutout can create edge effects that generate pulling and shear.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>It is also possible to cut the small ridges in the middle of the cushion if they cause irritation: the ridges of the cutout can irritate the skin (field feedback documented by the seller itself).<\/q><br><span class=\"bp-srcl\">Askned, Pudendal Channel Cushion \u2014 <a href=\"https:\/\/askned.com.au\/seating-sleeping-and-body-support\/body-support-and-comfort\/back-and-body-supports\/pudendal-channel-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Each support follows its part of the pelvis: tissues stay in place.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>Thanks to the double articulation he now has available, he can reach much farther and come back without generating as much back pain.<\/q><br><span class=\"bp-srcl\">S\u00e9bastien Bottau, physiotherapist, head of the dedicated Spine Unit \/ Back School space, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer), Essentia stool fitted with the APORIA\u00ae seat \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>Each articulated support follows its part of the pelvis: the support moves with the tissues instead of sliding under them.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Doctrinal position: each support follows its part of the pelvis; sliding is not being followed (distinction between friction and shear maintained) [INTERNAL MODEL].<\/q><br><span class=\"bp-srcl\">SBNFA\u2122 doctrine \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr class=\"bp-fam\"><th colspan=\"5\" scope=\"rowgroup\">C. Balance<\/th><\/tr>\n<tr><td><a href=\"#c1\"><strong>C1. Balance regulation possibilities<\/strong><\/a><br><span class=\"bp-fr\">Are the hips free to steer balance, each according to its own movement, as when standing?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Hips locked, and therefore no way to steer balance: only 1 upright position.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>A coccyx cushion (U-shape) has solid support at the front and sides \u2014 making it more stable on office chair surfaces: stable, but balance is steered by the trunk, not by the hips.<\/q><br><span class=\"bp-srcl\">Cusheal, Buyer&#8217;s Guide \u2014 <a href=\"https:\/\/cusheal.com\/blogs\/blog\/best-tailbone-cushion-buyers-guide\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Hips locked, balance heavily penalized by the reported chronic instability.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>You balance on the rim, and the ring tilts when you shift.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Using them on my current office chair seems like it&#x27;s changing how my back hits the chair, and now I&#x27;m dealing with lower back stiffness.<\/q><br><span class=\"bp-srcl\">User, pudendal neuralgia forum (Reddit) \u2014 <a href=\"https:\/\/www.reddit.com\/r\/PudendalNeuralgia\/comments\/1f8dxol\/office_chair_recommendation\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>User testimonial<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Hips locked, and therefore no way to steer balance: only 1 upright position.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>The optional straps serve to \u201cstabilize the cushion and prevent it from slipping due to movement\u201d: balance is achieved against the cushion, not with it.<\/q><br><span class=\"bp-srcl\">Ergotech, product options \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Full release of decoupled hip mobility in 3D. Balance steered within a cone of functional economy (\u00b1 45\u00b0).<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>It gives us very interesting static positioning, especially in positions that were previously impossible on ordinary armchairs or chairs.<\/q><br><span class=\"bp-srcl\">S\u00e9bastien Bottau, physiotherapist, head of the dedicated Spine Unit \/ Back School space, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer), Essentia stool fitted with the APORIA\u00ae seat \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>Curved base: tilt in all directions; the hips remain free to steer balance.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>\u201cThe P\u00e9rin\u00e9e cushion has allowed me [\u2026] to regain my independence by being able to drive.\u201d<\/q><br><span class=\"bp-srcl\">B\u00e9atrice D., customer testimonial \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Testimonial hosted by Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr><td><a href=\"#c2\"><strong>C2. Adjustments of the musculoskeletal system<\/strong><\/a><br><span class=\"bp-fr\">Is regulation of adjustments through pelvic movement in the horizontal plane (translation and rotation) possible?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Translation possible: freedom of movement through foam give (~1 cm).<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Selection criterion: dimensions suited to the seat, with a non-slip base: foam give is the only room for translation.<\/q><br><span class=\"bp-srcl\">Orthoptimal \u2014 <a href=\"https:\/\/orthoptimal.fr\/blogs\/ortho-conseils-le-blog\/coussin-orthopedique-fessier-lequel-choisir-en-cas-de-douleur-au-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Pelvic movements made very difficult by the ring&#8217;s unstable load-bearing.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Unstable cushions put more demand on stabilizing muscles and create unnecessary fatigue.<\/q><br><span class=\"bp-srcl\">Sihoo, expert guide \u2014 <a href=\"https:\/\/fr.sihoo.com\/blogs\/guide-dachat\/chaise-bureau-douleur-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Translation possible: freedom of movement through foam give (~1 cm).<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Straps to stabilize the cushion and prevent it from slipping due to movement: horizontal movement has to be countered with straps rather than followed.<\/q><br><span class=\"bp-srcl\">Ergotech \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">The freed hips drive translation (1 to 2 cm) and also rotation (10\u00b0) with no return force (stabilized movements). Placed on a chair, the cushion does not turn with the upper body. <strong>Level 3, not 4<\/strong>: translation and rotation remain limited.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Rotation of 10\u00b0 and translation of 1 to 2 cm in the horizontal plane; placed on a chair, the cushion does not turn with the upper body.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr><td><a href=\"#c3\"><strong>C3. Management of lumbopelvic compensations<\/strong><\/a><br><span class=\"bp-fr\">Does the seat allow the sacroiliac joints to keep their natural mobility, as when standing, so as not to hinder compensations between the upper and lower body?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">One-piece seat: SI joints constrained, but the give of the supporting foam allows very slight sagittal mobility (nutation and counter-nutation).<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>In the medium and long term, a seat that locks the pelvis causes tonic inhibition of the postural muscles; the opposing muscles compensate constantly.<\/q><br><span class=\"bp-srcl\">Clinique OPS \u2014 <a href=\"https:\/\/www.cliniqueops.com\/pathologies-posturales\/coussin-postural-sur-mesure-blog-article-217-fr.htm\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">The rim locks the pelvis in place and leaves no play for the sacroiliac joints.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Prolonged use locks the pelvis and reduces the variability of postural tone (applied here to the rim of the ring).<\/q><br><span class=\"bp-srcl\">Clinique OPS (cross-reading) \u2014 <a href=\"https:\/\/www.cliniqueops.com\/pathologies-posturales\/coussin-postural-sur-mesure-blog-article-217-fr.htm\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">One-piece seat: SI joints constrained by the support.<\/div><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">The 2 mobile and decoupled rear supports do not hinder fluid and continuous mobility of the SI joints (nutation, counter-nutation, transverse rotation).<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Independent rear supports on the left and right: each side of the pelvis keeps its mobility.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr><td><a href=\"#c4\"><strong>C4. Adaptation to the natural balance profile<\/strong><\/a><br><span class=\"bp-fr\">Is the tilt of the seat surface adjustable, or does it force anteverted, neutral, or retroverted positions in line with the 3 types of spinal profile?<\/span><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Imposed orientation, with no possible adjustment: horizontal, or tilted forward, depending on the model. A fixed forward-sloping surface imposes an orientation that may suit the hyperlordotic profile (type 4), which accounts for about 15% of subjects in several recent cohorts. For the other profiles, this orientation is not an individual adaptation to their natural sagittal balance.<\/div><details class=\"bp-src\"><summary>Feedback and sources (5)<\/summary><ul><li><q>Not only do you impose a plane, you impose an incidence, but in a way you do not know whether the incidence you impose suits the individual&#8217;s cone.<\/q><br><span class=\"bp-srcl\">Pierre Ivaldi, physiotherapist and osteopath, former managing director (30 years) of the Saint-Jean group&#8217;s post-acute care and functional rehabilitation center, originator of several foundations of the SBNFA\u2122 framework \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>Systematic review of sagittal profile distributions (Roussouly classification) in asymptomatic adults, 2005-2025: the neutral profile (type 3) is the most common, but a majority of the population has another profile.<\/q><br><span class=\"bp-srcl\">Systematic review 2025, \u201cNormative sagittal spinopelvic profiles: a systematic review of the Roussouly classification across different ethnic groups in asymptomatic adults\u201d (PubMed 42104183) \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/42104183\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Study<\/em><\/span><\/li><li><q>A cushion with an excessively steep slope may push the pelvis too far forward and exaggerate the curve in the lower back.<\/q><br><span class=\"bp-srcl\">Your Body Posture \u2014 <a href=\"https:\/\/yourbodyposture.com\/best-seat-wedges-anterior-pelvic-tilt\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>General-audience article<\/em><\/span><\/li><li><q>For taller users, it may raise the seating position too much if the cushion is thick and the seat is not height-adjustable.<\/q><br><span class=\"bp-srcl\">Ergotech, limitations of the wedge \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/smartblog\/290_top-3-car-seat-cushions.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Roussouly (2005): 4 sagittal profiles; Korean study 2017: 49.6% neutral, 23% type 1, 13.1% flat back, 14.3% hyperlordotic; no imposed seat suits everyone.<\/q><br><span class=\"bp-srcl\">Korean study 2017, \u201cEvaluation of Global Sagittal Balance in Korean Adults,\u201d J Korean Neurosurg Soc 2017;60(5):560-566 \u2014 <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC5594629\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Study<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Orientation constantly disturbed by the deformation of the crown when sitting.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Since you settle partway into the hole rather than onto a surface, your final sitting height is hard to predict.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>The cushion raises you by 5 to 10 cm, making the lumbar support of the backrest ineffective.<\/q><br><span class=\"bp-srcl\">Sihoo \u2014 <a href=\"https:\/\/fr.sihoo.com\/blogs\/guide-dachat\/chaise-bureau-douleur-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Imposed orientation (often tilted forward).<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Alcock Rest is thicker at the back than at the front. This difference in thickness aims to elevate the buttocks to open the pelvic: anteversion is imposed by design, with no possible backward adjustment.<\/q><br><span class=\"bp-srcl\">Ergotech, product sheet (manufacturer&#8217;s own statement) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>This seating cushion is quite thick (5 cm at the back) and may raise you too high in the car seat.<\/q><br><span class=\"bp-srcl\">Ergotech, manufacturer&#8217;s warning \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">5 adjustable positions: small or large wedge adapting the tilt to the balance profile, placed at the front for flatter-back profiles, at the back for more lordotic profiles; no wedge for the neutral profile. Step-by-step adjustment. <strong>Level 3, not 4<\/strong>: adjustment is made through successive positions, not continuously.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>The support shell allows different position settings.<\/q><br><span class=\"bp-srcl\">Dr. Anne Lassaux, pain physician, head of the Pain Assessment and Treatment department, Rothschild Hospital AP-HP until the end of June 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/shared-experiences\/aporia-reviews-dynamic-seating\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Pain physician, no declared conflict of interest<\/em><\/span><\/li><li><q>Two wedges, small and large, placed at the front or the back, or no wedge: 5 positions, step-by-step adjustment according to profile.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Systematic review of sagittal profile distributions (Roussouly classification) in asymptomatic adults, 2005-2025: the neutral profile (type 3) is the most common, but a majority of the population has another profile.<\/q><br><span class=\"bp-srcl\">Systematic review 2025, \u201cNormative sagittal spinopelvic profiles: a systematic review of the Roussouly classification across different ethnic groups in asymptomatic adults\u201d (PubMed 42104183) \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/42104183\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Study<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr>\n<tr class=\"bp-ex\"><td>Brand examples<\/td><td>Travel Ease, Feagar, Sameo, The Original McKenzie, Putnams, feela<\/td><td>Inphysio, Harley, Putnams, bonmedico, Aidapt<\/td><td>KHOL, Ergotech Alcock Rest, Algicare, Pro Physio, Systergo, Ergosia<\/td><td>APORIA\u00ae (Blue Portance)<\/td><\/tr>\n<\/tbody><\/table><\/div>\n<p>The levels describe the architecture of each family. Real-world use of APORIA\u00ae (satisfaction study at CHU de Nantes, pain physician, spinal rehabilitation, 85% kept after a 30-day trial) is presented in <a href=\"#preuves-usage\">What does real-world use of APORIA\u00ae show?<\/a> The data from the CHU de Nantes study are presented in the <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/sitting-related-pain\/pelvi-seat-study-chu-nantes\/\">study file<\/a>.<\/p><\/section>\n<p class=\"bp-suite\"><a href=\"#partie-c\">See the details, attribute by attribute \u2193<\/a><\/p>\n<div class=\"bp-partie\" id=\"partie-c\" role=\"note\"><p class=\"bp-partie-n\">Part C<\/p><p class=\"bp-partie-t\">The detailed analysis, attribute by attribute<\/p><\/div>\n<p class=\"bp-direct\">The eleven attributes are detailed below, starting from the questions asked by people who are in pain when sitting. Each sheet carries its code: pressure (A1 to A4), movement and tissues (B1 to B3), balance (C1 to C4). Each follows the same path: the function sought, the four levels, APORIA\u00ae&#8217;s response, then the level of each cushion family, with its sources.<\/p>\n<section id=\"decharge\"><h2>Does pressure offloading really bring relief when sitting?<\/h2>\n<p class=\"bp-direct\">Yes, taking the painful zone off the seat often brings relief within the first few minutes. But offloading solves only part of the problem: the weight shifts elsewhere, tissues can stay under tension, and the pelvis can end up locked.<\/p>\n<p>Above all, sitting pain does not come from pressure alone. Sitting without moving, the body deteriorates from the inside:<\/p>\n<ul>\n<li><strong>Creep.<\/strong> Under a load that does not vary, tissues slowly compact and lose their suppleness.<\/li>\n<li><strong>Internal compression.<\/strong> The pelvic floor muscles lock in hypertonia and compress the nerves from the inside. No cutout acts on this compression.<\/li>\n<li><strong>Fascial degradation.<\/strong> These tissues are among the richest in the body in nerve sensors (mechanoreceptors). Damaged, they sustain pain: that is why it persists.<\/li>\n<li><strong>Dehydration.<\/strong> Deprived of movement, the fasciae dry out and stop gliding.<\/li>\n<li><strong>Adhesions.<\/strong> Tissues stick around the nerve. The nerve no longer glides and is pulled with every movement.<\/li>\n<\/ul>\n<p>That is why a cushion is not judged on its offloading alone. This guide asks it eleven questions, one per attribute: pressure (<a href=\"#a1\">A1<\/a> to <a href=\"#a4\">A4<\/a>), movement and tissues (<a href=\"#b1\">B1<\/a> to <a href=\"#b3\">B3<\/a>), balance (<a href=\"#c1\">C1<\/a> to <a href=\"#c4\">C4<\/a>). The questions below explain why, and point to the attributes that measure it.<\/p>\n<h3 id=\"pourquoi-decharge\">Why does offloading bring relief?<\/h3>\n<p>When a zone is painful (perineum, tailbone), you need to stop putting weight on it. An offloading cutout takes it out of contact; its shape still has to match the zone: wide enough not to touch it, with no edge that marks the surrounding tissues. A badly placed or badly sized cutout leaves the zone loaded or shifts the pressure to its edges: the pain persists.<\/p>\n<section class=\"bp-fiche\" id=\"a1\"><h3>How does a cushion take the tailbone or the perineum off the seat?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute A1 \u2014 Offloading of the painful zone<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> Is the painful zone taken off the seat, and is the offloading suited to that zone?<\/p>\n<table class=\"bp-gradation\"><caption>A1. Offloading of the painful zone \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>Direct load on the zone<\/td><\/tr>\n<tr><td>2<\/td><td>Reduced pressure on the zone<\/td><\/tr>\n<tr><td>3<\/td><td>Zone out of contact<\/td><\/tr>\n<tr><td>4<\/td><td>Out of contact, geometry suited to the zone<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> The out-of-contact zone is identified (center, back, midline) and, with the person seated, it is checked that it stays out of contact under load and that its edges do not mark the tissues.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">Aporia\u00ae comes in four offloading versions: Standard, P\u00e9rin\u00e9e, Coccyx, and Canyon. The offloading is formed by the space between the supports, and its shape follows the zone to be protected. Because the supports are mobile, the offloaded zone has no fixed edge against which tissues are stretched.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>A1: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Cut-out zone: tailbone (rear cutout). The tailbone is out of contact; the perineum remains loaded. Rear offloading of the tailbone and the sacrococcygeal region, suited to pain located in this zone.<\/div><details class=\"bp-src\"><summary>Feedback and sources (4)<\/summary><ul><li><q>The mechanism is simple: the opening lets the coccyx float in free air rather than bear any body weight.<\/q><br><span class=\"bp-srcl\">Flexi Chair, Best Coccyx Cushions 2026 \u2014 <a href=\"https:\/\/flexi-chair.com\/accessories\/best-coccyx-cushions-tailbone-pain-2026\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>U-cutout: the tailbone stays free, weight is shifted onto the sit bones.<\/q><br><span class=\"bp-srcl\">Orthexa, coccyx cushion \u2014 <a href=\"https:\/\/orthexa.fr\/coussin-coccyx-pour-soulager-la-douleur-assise\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Foye 2009 study (Rutgers, 55 patients with coccydynia): those who state a preference choose the beveled cutout cushion almost 5 times more often than the donut; 42% prefer neither (preference, not efficacy).<\/q><br><span class=\"bp-srcl\">Live Hearth Well, reporting the Foye 2009 abstract \u2014 <a href=\"https:\/\/livehearthwell.com\/en\/guides\/coccyx-cushion-guide\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Study<\/em><\/span><\/li><li><q>The trade-off is that the tailbone is not fully unloaded. For acute, sharp tenderness, a partial cutout can still be too much contact.<\/q><br><span class=\"bp-srcl\">Grabberstool, Donut vs Wedge \u2014 <a href=\"https:\/\/grabberstool.com\/blogs\/news\/donut-cushion-vs-wedge-cushion-tailbone\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Cut-out zone: center (ring). The central zone is out of contact; the load shifts to the ring. Continuous rim at the back: the ring still bears on the sacrococcygeal region.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>Check that the opening is positioned correctly to avoid a misplaced pressure ridge.<\/q><br><span class=\"bp-srcl\">Orvimed, SYSTAM donut cushion product sheet \u2014 <a href=\"https:\/\/www.orvimed.fr\/maintien-a-domicile\/54-coussin-de-positionnement-bouee.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>The rear part of the ring can press on the tailbone or the lower sacrum.<\/q><br><span class=\"bp-srcl\">Orthoptimal, shapes and selection criteria \u2014 <a href=\"https:\/\/orthoptimal.fr\/blogs\/ortho-conseils-le-blog\/coussin-orthopedique-fessier-lequel-choisir-en-cas-de-douleur-au-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>If the targeted area makes contact, the pillow is incorrectly sized, positioned, or too soft for your body weight.<\/q><br><span class=\"bp-srcl\">Biology Insights, How to Sit on a Donut Pillow \u2014 <a href=\"https:\/\/biologyinsights.com\/how-to-sit-on-a-donut-pillow-for-maximum-relief\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>General-audience article<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Cut-out zone: perineum, often tailbone. The perineum, and often the tailbone, are out of contact. Offloading suited to perineal pain.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>A wedge or seat cushion with a front-to-back channel or cutout tends to work best, because it offloads the entire midline from the tailbone through the perineum while your weight rests on the thighs and sit bones.<\/q><br><span class=\"bp-srcl\">Dr. R. Naples (urologist), How to Sit With Pudendal Neuralgia \u2014 <a href=\"https:\/\/www.drrnaples.com\/how-to-sit-with-pudendal-neuralgia\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><li><q>Relieve pressure on sacrum and perineum, including the Alcock&#x27;s canal where the pudendal nerve is located. [\u2026] provides relief to the entire area from the sacrum to the perineum.<\/q><br><span class=\"bp-srcl\">Ergotech, Alcock Rest product sheet \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>The very best. Without this cushion, the mechanical pressure on the pudendal nerve when sitting is so intense that I cannot sit down without feeling pain. I have been using it for 2 years.<\/q><br><span class=\"bp-srcl\">J\u00e9r\u00e9my H., verified customer review, Alcock Rest (5\u2605) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Review hosted by the seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Cut-out zone depending on the version: perineum, tailbone, full channel. The offloading is formed by the space between the mobile supports.<\/div><details class=\"bp-src\"><summary>Feedback and sources (4)<\/summary><ul><li><q>The painful zones are freed from load.<\/q><br><span class=\"bp-srcl\">Dr. Anne Lassaux, pain physician, head of the Pain Assessment and Treatment department, Rothschild Hospital AP-HP until the end of June 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/shared-experiences\/aporia-reviews-dynamic-seating\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Pain physician, no declared conflict of interest<\/em><\/span><\/li><li><q>Regarding pain relief, the APORIA N\u00b01 seat seems to relieve cluneal and pudendal pain, and the APORIA N\u00b02 seat, for its part, seems to relieve tailbone pain.<\/q><br><span class=\"bp-srcl\">User satisfaction study, pelvic pain unit of CHU de Nantes, Dr. Am\u00e9lie Seneau L\u00e9vesque, report of December 13, 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/sitting-related-pain\/pelvi-seat-study-chu-nantes\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Hospital study<\/em><\/span><\/li><li><q>Offloading formed by the space between the four supports: the painful zone is out of contact.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>6 cm central offloading: four supports on ball joints follow the small movements of the pelvis without locking it or throwing it off balance.<\/q><br><span class=\"bp-srcl\">Blue Portance, manufacturer&#8217;s position \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-a1\">Sources for attribute A1<\/a><\/p><\/section>\n<h3 id=\"decharge-suffit\">Is offloading enough to relieve the pain?<\/h3>\n<p>Not always. The weight removed from the cut-out zone shifts to the rest of the surface: sit bones, thighs, edges of the cutout. If this load stays fixed and concentrated, the pain can move or come back. This is what is measured by <a href=\"#a2\">static pressure distribution (A2)<\/a>, <a href=\"#a3\">dynamic pressure distribution (A3)<\/a> and <a href=\"#a4\">load variability (A4)<\/a>.<\/p>\n<h3 id=\"douleur-revient\">Why does the pain persist or come back despite a cushion with a hole?<\/h3>\n<p>A cutout removes direct load, not pulling. When the pelvis moves on a fixed surface, the skin and the tissues around the tailbone or perineum are stretched: this is shear. The edge of the cutout, or the rim of a donut, can also concentrate pressure. See <a href=\"#b3\">protection against shear and pulling (B3)<\/a> and <a href=\"#a3\">dynamic pressure distribution (A3)<\/a>.<\/p>\n<p>The pain also persists because a fixed cushion shuts down micromovements. Without them, tissues compact (creep), dehydrate, and adhere around the nerve, which no longer glides. The muscles stay in hypertonia and compress the nerve from the inside. The fasciae, very richly innervated, keep sending pain signals, even without direct load. See <a href=\"#b1\">micromovements and mechanotransduction (B1)<\/a>, <a href=\"#a4\">load variability (A4)<\/a> and <a href=\"#b2\">three-dimensional pelvic mobility (B2)<\/a>.<\/p>\n<h3 id=\"coccyx-sans-bloquer\">Which cushion offloads the tailbone without locking the pelvis?<\/h3>\n<p>You need offloading that stays in place when the pelvis moves: forward-backward and lateral tilts, small rotations and translations, play of the sacroiliac joints. On a one-piece cushion, these movements happen against the support; on a seat with independent supports, the supports follow the pelvis and the cut-out zone stays clear. See <a href=\"#b1\">micromovements (B1)<\/a>, <a href=\"#b2\">three-dimensional pelvic mobility (B2)<\/a>, <a href=\"#c2\">adjustments of the musculoskeletal system (C2)<\/a> and <a href=\"#c3\">management of lumbopelvic compensations (C3)<\/a>.<\/p>\n<h3 id=\"perinee-sans-imposer\">Which cushion offloads the perineum without imposing a position?<\/h3>\n<p>A perineal cutout should not lock the pelvis in a single orientation. A fixed sloped surface imposes the same position on everyone; a seat whose orientation is set according to the profile (arched, neutral, or flat back) and that lets balance adjust respects each person&#8217;s natural position. See <a href=\"#c1\">balance regulation possibilities (C1)<\/a> and <a href=\"#c4\">adaptation to the natural balance profile (C4)<\/a>.<\/p>\n<\/section>\n<section id=\"inconfortable\"><h2>Why does a cushion bring relief at first and then become uncomfortable?<\/h2>\n<p class=\"bp-direct\">A cushion can be comfortable at first, then become uncomfortable when the foam sags, when pressure concentrates on an edge, or when the pelvis can no longer move freely. So the question is not only \u201cis it soft?\u201d but \u201cdoes the pressure redistribute when I move?\u201d<\/p>\n<section class=\"bp-fiche\" id=\"a2\"><h3>Why do my buttocks hurt after sitting for a long time?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute A2 \u2014 Static pressure distribution<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> At rest, is pressure uniform across the entire contact surface?<\/p>\n<p>When seated, most of the body&#8217;s weight rests on the sit bones. A rigid surface concentrates pressure there, and the tissues suffer. A good seat enlarges the contact surface and distributes pressure evenly: no point stays overloaded. The more the surface molds to the body&#8217;s contours and divides into segments that each compress according to their load, the more uniform the distribution. This attribute concerns the seat at rest; distribution during movement belongs to attribute A3.<\/p>\n<table class=\"bp-gradation\"><caption>A2. Static pressure distribution \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>Rigid surface<\/td><\/tr>\n<tr><td>2<\/td><td>Localized sinking<\/td><\/tr>\n<tr><td>3<\/td><td>Sinking that molds to the contours<\/td><\/tr>\n<tr><td>4<\/td><td>Each zone compresses according to its load (for example, segmented seat with pads, the family of pressure ulcer prevention cushions)<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> With the person still, it is observed whether the contact surface sinks locally, molds to the contours, or compresses zone by zone; pressure mapping can confirm the observation.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">The four segmented supports, filled with memory foam, each compress according to the load they receive. Pressure is distributed across the entire contact surface. An anti-bottoming layer prevents any contact with the base.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>A2: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Memory foam molds to the contours.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Memory foam deforms under body heat and weight, then molds to the shape of the pelvis, which spreads the load over a larger surface.<\/q><br><span class=\"bp-srcl\">Orthexa \u2014 <a href=\"https:\/\/orthexa.fr\/coussin-coccyx-pour-soulager-la-douleur-assise\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Some users report that the cushion compresses over time, potentially reducing support.<\/q><br><span class=\"bp-srcl\">User reviews reported by Corner Office HQ \u2014 <a href=\"https:\/\/cornerofficehq.com\/best-coccyx-seat-cushions\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>User testimonial<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Sinking concentrates on the crown of the ring.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>A donut does not eliminate pressure. It moves the same pounds onto less area, on a delay.<\/q><br><span class=\"bp-srcl\">Aylio, Donut vs twin cutouts \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Over a long sit, the rim becomes the new pressure point.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Within a few days the memory foam compresses and becomes uncomfortable (customer feedback on flattening, especially above 100 kg).<\/q><br><span class=\"bp-srcl\">Customer reviews, The White Willow \u2014 <a href=\"https:\/\/thewhitewillow.in\/products\/sky-hr-foam-donut-shaped-seat-cushion-tailbone-and-lumber-support-firm\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>User testimonial<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Memory foam molds to the contours around the cutout.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Higher-density foam on the outside and softer foam in the center. This reduces pressure on the perineal area when sitting.<\/q><br><span class=\"bp-srcl\">Pelican Manufacturing, Pudendal Channel Cushion \u2014 <a href=\"https:\/\/pelicanmanufacturing.com\/product\/pudendal-channel-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Distributes pressure across thighs and buttocks, ideal for muscular sensitivity.<\/q><br><span class=\"bp-srcl\">Ergotech, comparison of Alcock Rest versions \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/smartblog\/307_comparison-pudendal-cushion.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Each of the 4 memory foam supports carries the load it receives.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>The foam \u201cpads\u201d adapt to different anatomies by adjusting individually.<\/q><br><span class=\"bp-srcl\">Dr. Anne Lassaux, pain physician, head of the Pain Assessment and Treatment department, Rothschild Hospital AP-HP until the end of June 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/shared-experiences\/aporia-reviews-dynamic-seating\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Pain physician, no declared conflict of interest<\/em><\/span><\/li><li><q>Four independent memory foam supports: each one receives and carries its share of the load.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Four supports on ball joints follow the small movements of the pelvis without locking it or throwing it off balance.<\/q><br><span class=\"bp-srcl\">Blue Portance, manufacturer&#8217;s position \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-a2\">Sources for attribute A2<\/a><\/p><\/section>\n<section class=\"bp-fiche\" id=\"a3\"><h3>Why does the pain come back when I move?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute A3 \u2014 Dynamic pressure distribution<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> Does pressure stay uniform during movement?<\/p>\n<p>Distributing pressure well at rest is not enough: when seated, you never stay still. You lean, turn, reach for an object, and with each movement the load shifts. A seat that follows the pelvis support by support keeps pressure uniform, whatever the position. Otherwise, each movement creates a pressure peak on one zone, often under a sit bone or at the edge of the seat: tissues are crushed in jolts, and the distribution achieved at rest is lost as soon as you move.<\/p>\n<table class=\"bp-gradation\"><caption>A3. Dynamic pressure distribution \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>Distribution lost: as soon as you lean, the load concentrates on one zone (pressure peak)<\/td><\/tr>\n<tr><td>2<\/td><td>Distribution regained only after repositioning<\/td><\/tr>\n<tr><td>3<\/td><td>Distribution maintained in one plane only (seat that tilts as a block, on one axis)<\/td><\/tr>\n<tr><td>4<\/td><td>Distribution maintained in all positions and all movements: each support zone adapts to the load it receives<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> The person is asked to lean and turn, and it is observed whether the load concentrates on one zone or edge, or whether each zone keeps compressing according to its load.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">The four independent supports rest on a curved base. When the body leans or turns, the base follows the movement and each support, filled with memory foam, compresses according to the load it receives, in every position: the load is redistributed between the supports instead of concentrating on one zone.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>A3: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">When you lean forward, the load concentrates; you have to reposition yourself.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Cutout placed behind the tailbone, without tilting the pelvis forward; non-slip base (criteria for stability during movement).<\/q><br><span class=\"bp-srcl\">Orthoptimal \u2014 <a href=\"https:\/\/orthoptimal.fr\/blogs\/ortho-conseils-le-blog\/coussin-orthopedique-fessier-lequel-choisir-en-cas-de-douleur-au-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">When you lean, the load shifts to one side of the ring.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>A ring puts a hole in the middle of your base of support, so you balance on the rim, and the ring tilts when you shift. Inflatable donuts add a second wobble, because air moves away from wherever you press.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Slouching shifts your weight backward, which can push the sensitive area against the rear rim of the cushion.<\/q><br><span class=\"bp-srcl\">Biology Insights \u2014 <a href=\"https:\/\/biologyinsights.com\/how-to-sit-on-a-donut-pillow-for-maximum-relief\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>General-audience article<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">When you lean forward, the load concentrates; you have to reposition yourself.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Small, frequent changes in position usually help more than trying to find one perfect way to sit.<\/q><br><span class=\"bp-srcl\">Dr. R. Naples \u2014 <a href=\"https:\/\/www.drrnaples.com\/how-to-sit-with-pudendal-neuralgia\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><li><q>The fluid pouches can also be detached and moved to adapt to your pressure points while sitting (HV fluid version: manual adjustment possible, but no automatic following of movement).<\/q><br><span class=\"bp-srcl\">Ergotech, Alcock Rest usage advice \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">The base follows the movement and each of the 4 articulated supports adapts to its load.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>Mobile base and four articulated supports: when you lean, each support adapts to the load it receives.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Average customer rating: 4.7\/5.<\/q><br><span class=\"bp-srcl\">Trustpilot, Blue Portance reviews \u2014 <a href=\"https:\/\/fr.trustpilot.com\/review\/blueportance.com\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Independent review platform<\/em><\/span><\/li><li><q>The multi-articulated structure adapts continuously to help the body regulate its center of mass.<\/q><br><span class=\"bp-srcl\">APORIA\u00ae doctrinal position [INTERNAL MODEL] \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-a3\">Sources for attribute A3<\/a><\/p><\/section>\n<section class=\"bp-fiche\" id=\"a4\"><h3>Why is sitting for a long time tiring?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute A4 \u2014 Load variability<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> Does the load move from zone to zone over time, and at whose pace?<\/p>\n<p>It is not so much the pressure as its persistence that causes the problem. Pressure that never moves compresses tissues, slows circulation, and promotes their dehydration and fascial adhesions. Varying the load gives tissues phases of offloading during which they are reperfused: this is the principle of pressure-relief mattresses. Ideally, the load passes from one support to another at the body&#8217;s own pace.<\/p>\n<table class=\"bp-gradation\"><caption>A4. Load variability \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>No variation: fixed support, monotonous stress<\/td><\/tr>\n<tr><td>2<\/td><td>Imposed monotonous variation (uniform vibrations, repetitive mechanical alternation)<\/td><\/tr>\n<tr><td>3<\/td><td>Overall multidirectional variation: the seat moves, but as a block<\/td><\/tr>\n<tr><td>4<\/td><td>Adaptive variation, zone by zone: the load passes from one zone to another at the body&#8217;s pace<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> It is observed whether the load changes zone over time, whether this variation is imposed by a mechanism or follows the person&#8217;s movements, and whether it happens as a block or zone by zone.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">The four independent supports share the load. As soon as the body moves, the load passes from one support to another: one zone takes on load, another is relieved. The body sets the pace, not a mechanism. Even after hours of sitting, no zone stays loaded continuously.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>A4: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Fixed support, constant stress with little variation; memory foam brings some pressure variability with movement.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Prolonged use locks the pelvis in anteversion and the lumbar spine in extension, reducing the variability of postural tone.<\/q><br><span class=\"bp-srcl\">Clinique OPS (sloped versions) \u2014 <a href=\"https:\/\/www.cliniqueops.com\/pathologies-posturales\/coussin-postural-sur-mesure-blog-article-217-fr.htm\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Fixed support on the ring, constant stress with erratic variation due to the ring&#8217;s unstable load-bearing.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Tissue under sustained load compresses, and a narrow ring pressing into the underside of the thighs and the outer glutes carries your whole weight on that thin band of contact.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Fixed support, constant stress with little variation.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>One-piece cushion: the fluid pouches can be moved by hand from one session to the next, but while sitting the support stays fixed.<\/q><br><span class=\"bp-srcl\">Ergotech (reading of the product options) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">The multi-articulated structure adapts continuously to help the body regulate its center of mass; each support sees its pressure vary with the rhythm of movement.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>It also appears that the APORIA N\u00b01 and APORIA N\u00b02 seats offer greater comfort than the cushions or other products used by patients in everyday life.<\/q><br><span class=\"bp-srcl\">User satisfaction study, pelvic pain unit of CHU de Nantes, Dr. Am\u00e9lie Seneau L\u00e9vesque, report of December 13, 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/sitting-related-pain\/pelvi-seat-study-chu-nantes\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Hospital study<\/em><\/span><\/li><li><q>Base and articulated supports: the load moves continuously under each support, giving tissues phases of offloading.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Four supports on ball joints follow the small movements of the pelvis without locking it or throwing it off balance.<\/q><br><span class=\"bp-srcl\">Blue Portance \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-a4\">Sources for attribute A4<\/a><\/p><\/section>\n<section class=\"bp-fiche\" id=\"b3\"><h3>Why do I feel pulling when I turn?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute B3 \u2014 Protection against shear and pulling<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> When the pelvis moves, is the movement followed by the seat, or paid for by the tissues?<\/p>\n<p>When the upper body turns, the pelvis partly turns with it: one buttock moves forward, the other back. A seat that follows this movement zone by zone leaves the tissues in place on their support. On a one-piece seat, the skin grips while the deep layers move: the tissues are sheared and, through their attachments, pull on deep structures (tailbone, sacrum, ligaments through which the pudendal nerve runs). Offloading removes direct load, not this pulling. It creates chains of internal stress that sustain pain, even when nothing presses on the zone anymore.<\/p>\n<table class=\"bp-gradation\"><caption>B3. Protection against shear and pulling \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>Movement paid for by the tissues: the one-piece surface holds the skin while the deep layers move<\/td><\/tr>\n<tr><td>2<\/td><td>Sliding as a block: the body slips on the surface; pulling decreases, but the position is lost<\/td><\/tr>\n<tr><td>3<\/td><td>Movement followed in one plane only; shear persists in the others<\/td><\/tr>\n<tr><td>4<\/td><td>Movement followed zone by zone, in all three planes: tissues stay in place on their support<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> During trunk rotation, it is observed whether the surface follows each side of the pelvis, whether the body slides on the surface as a block, or whether the surface stays fixed while the pelvis turns.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">Each support follows its part of the pelvis: when the upper body turns, the left support moves forward while the right one moves back. The support follows the skin instead of holding it: sliding between the tissues and their support, the source of shear, is eliminated at the interface; the offloading truly remains offloading.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>B3: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">The one-piece cushion can resist movement; memory foam reduces shear.<br><b>Special case: level 3\/4 <span class='stars'>\u2605\u2605\u2605\u2606<\/span><\/b><br>Cushions with cells or pads that follow movement.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Foam that is too soft compresses completely and lets the tailbone touch the seat again, with no real benefit.<\/q><br><span class=\"bp-srcl\">Orthexa \u2014 <a href=\"https:\/\/orthexa.fr\/coussin-coccyx-pour-soulager-la-douleur-assise\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>A flat cushion with cutouts is structurally just a flat cushion. It stays where you put it: a stable but one-piece surface (it holds the skin during movement).<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">The edge effect of the crown increases pulling, a phenomenon known as the \u201cring problem.\u201d<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Concentration is not a side effect of the donut shape \u2014 it is the shape.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">The cushion with its central cutout can create edge effects that generate pulling and shear.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>It is also possible to cut the small ridges in the middle of the cushion if they cause irritation: the ridges of the cutout can irritate the skin (field feedback documented by the seller itself).<\/q><br><span class=\"bp-srcl\">Askned, Pudendal Channel Cushion \u2014 <a href=\"https:\/\/askned.com.au\/seating-sleeping-and-body-support\/body-support-and-comfort\/back-and-body-supports\/pudendal-channel-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Each support follows its part of the pelvis: tissues stay in place.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>Thanks to the double articulation he now has available, he can reach much farther and come back without generating as much back pain.<\/q><br><span class=\"bp-srcl\">S\u00e9bastien Bottau, physiotherapist, head of the dedicated Spine Unit \/ Back School space, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer), Essentia stool fitted with the APORIA\u00ae seat \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>Each articulated support follows its part of the pelvis: the support moves with the tissues instead of sliding under them.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Doctrinal position: each support follows its part of the pelvis; sliding is not being followed (distinction between friction and shear maintained) [INTERNAL MODEL].<\/q><br><span class=\"bp-srcl\">SBNFA\u2122 doctrine \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-b3\">Sources for attribute B3<\/a><\/p><\/section>\n<\/section>\n<section id=\"rester-assis\"><h2>Which cushion should you choose to sit for a long time without pain?<\/h2>\n<p class=\"bp-direct\">Some cushions stabilize a lot but can limit pelvic movement. Others let the pelvis move without necessarily following it. The right choice depends on your postural profile, how long you sit, and how you need to be able to adjust without effort.<\/p>\n<section class=\"bp-fiche\" id=\"b1\"><h3>Why doesn&#8217;t my cushion follow my small movements?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute B1 \u2014 Micromovements and mechanotransduction<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> Does the seat follow the body&#8217;s smallest spontaneous movements?<\/p>\n<p>The body never stops moving: breathing, postural sway, small reflex adjustments. These micromovements constantly stretch and relax the tissues, which stimulates them: this is mechanotransduction, which maintains and renews tissue. A seat that does not follow these micromovements shuts them down. The tissues become depleted and lose their suppleness and gliding, with the risk of adhesions forming around the nerves. The muscles lock in hypertonia, which compresses structures from the inside. This is a major source of pain when sitting.<\/p>\n<table class=\"bp-gradation\"><caption>B1. Micromovements and mechanotransduction \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>No response: fixed contact, the seat follows no movement<\/td><\/tr>\n<tr><td>2<\/td><td>Response to large movements only: the seat follows changes of position, not micromovements<\/td><\/tr>\n<tr><td>3<\/td><td>Response to voluntary micromovements: small adjustments of a few millimeters<\/td><\/tr>\n<tr><td>4<\/td><td>Response to spontaneous micromovements: breathing, postural sway, reflex adjustments, continuously and without effort<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> Very low-amplitude inputs are applied and an activation threshold, a dead zone, or a fixed contact is looked for.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">The four independent supports are like four small hands. Resting on a curved base, they follow the smallest movements of the pelvis and, in return, continuously stimulate and massage the tissues, effortlessly and without thinking about it. Even after hours of sitting, the tissues keep receiving the stimulation they need.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>B1: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Static seat: fixed contact.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>After 5 minutes of sitting, are you already starting to move? Positions that change every 5 minutes (the industry&#8217;s own marketing documents the need to move).<\/q><br><span class=\"bp-srcl\">Sameo, product sheet \u2014 <a href=\"https:\/\/www.sameo.fr\/products\/coussin-orthopedique-coccyx-sameo\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Static seat: fixed contact.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Maintaining a neutral spinal alignment is necessary [\u2026] avoiding any tendency to slouch or lean heavily to one side: proper use requires moving as little as possible.<\/q><br><span class=\"bp-srcl\">Biology Insights \u2014 <a href=\"https:\/\/biologyinsights.com\/how-to-sit-on-a-donut-pillow-for-maximum-relief\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>General-audience article<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Static seat: fixed contact.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Cushion well suited to my body shape, relief when sitting.<\/q><br><span class=\"bp-srcl\">Daniele W., verified customer review, Alcock Rest (4\u2605) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Review hosted by the seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Dynamic seat: each of the 4 articulated supports responds to the slightest input to follow and support.<\/div><details class=\"bp-src\"><summary>Feedback and sources (4)<\/summary><ul><li><q>I sit down, but I am not static on a cushion [\u2026] I look for my position. What matters is that the cushion can respond to my demand, not to its own.<\/q><br><span class=\"bp-srcl\">Pierre Ivaldi, physiotherapist and osteopath, former managing director (30 years) of the Saint-Jean group&#8217;s post-acute care and functional rehabilitation center, originator of several foundations of the SBNFA\u2122 framework \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>There is fluidity in the movement, so you feel accompanied by the cushion, which is mobile.<\/q><br><span class=\"bp-srcl\">Physiotherapy trainee in lumbar rehabilitation, Back School, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer), Essentia stool fitted with the APORIA\u00ae seat \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>User testimonial<\/em><\/span><\/li><li><q>Four supports on ball joints: each one responds to the slightest input from the pelvis.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>\u201cThe P\u00e9rin\u00e9e cushion has allowed me to eat sitting down, do DIY, and above all regain my independence by being able to drive.\u201d<\/q><br><span class=\"bp-srcl\">B\u00e9atrice D., customer testimonial \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Testimonial hosted by Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-b1\">Sources for attribute B1<\/a><\/p><\/section>\n<section class=\"bp-fiche\" id=\"b2\"><h3>Why do I feel locked when I sit?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute B2 \u2014 Three-dimensional pelvic mobility<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> Can the pelvis move freely in all three planes around its balance point?<\/p>\n<p>It is the hips that mobilize the pelvis: when seated, it tilts forward and back, inclines to the sides, and rotates in the horizontal plane, in constant micro-adjustments. Its reserve of movement, larger or smaller depending on the profile, always works symmetrically around its balance point. If the seat blocks one of these movements, or leaves the pelvis far from this point (when sitting down, it tilts about 20\u00b0 toward retroversion), it ends up at its end of range. Creep then sets in: tissues deform slowly and recover poorly, and muscles lock in spasm. After just one hour of sitting, this is measurable.<\/p>\n<table class=\"bp-gradation\"><caption>B2. Three-dimensional pelvic mobility \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>Constrained pelvis<\/td><\/tr>\n<tr><td>2<\/td><td>Limited transverse and lateral mobility: small range, quick end stop<\/td><\/tr>\n<tr><td>3<\/td><td>Free forward-backward and lateral tilts; axial rotation of the pelvis absent, or followed over a limited range<\/td><\/tr>\n<tr><td>4<\/td><td>Free mobility in all three planes: forward-backward and lateral tilts and axial rotation of the pelvis, with no end stop<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> The three planes are tested separately (forward-backward tilt, lateral inclination, rotation), and for each one the free range and the appearance of an end stop are noted.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">With Aporia\u00ae, the hips are completely freed. The base tilts in all directions (cone estimated at about \u00b145\u00b0), and the four articulated pads follow every movement of the pelvis: its mobility is complete and subtle, from large tilts to micro-adjustments. In the horizontal plane, placed on a chair, the cushion follows the rotation of the pelvis over 10\u00b0. Set to its natural balance profile, the pelvis is never held at its end of range: the condition for creep is removed.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>B2: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Forward-backward and lateral tilt remain possible. Free and independent rotation of the pelvis is impossible: the hips have no independent supports and the interface cannot follow the rotation.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Your pelvis tips forward. Your lower back curves inward rather than rounding outward.<\/q><br><span class=\"bp-srcl\">Ageproof, 3-week test of an 8\u00b0 wedge \u2014 <a href=\"https:\/\/www.ageproof.co.uk\/reviews\/devices\/sitting-wedge-review\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Product test<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Forward-backward and lateral tilts theoretically possible but, in practice, limited by the constraints of the ring&#8217;s geometry and the instability observed; the back is blocked by the rim.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>This configuration often causes the hips and pelvis to roll backward, forcing the lower back into a rounded, slumped position \u2014 a posterior pelvic tilt.<\/q><br><span class=\"bp-srcl\">Sit Cushion \u2014 <a href=\"https:\/\/sitcushion.com\/u-shape-coccyx-cushion-or-donut\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Donut pillows often force the user to slouch forward to balance on the front of the ring.<\/q><br><span class=\"bp-srcl\">Sit Cushion \u2014 <a href=\"https:\/\/sitcushion.com\/donut-pillows-vs-coccyx-cutouts-which-pressure-relief-cushion-is-right-for-you\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Forward-backward tilt remains possible. Lateral tilt is uncomfortable (weight shifted onto a small area). Free and independent rotation of the pelvis is impossible: the hips have no independent supports and the interface cannot follow the rotation.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Weight rests on the thighs and sit bones: the channel frees the midline, while the lateral support stays on a reduced surface.<\/q><br><span class=\"bp-srcl\">Dr. R. Naples \u2014 <a href=\"https:\/\/www.drrnaples.com\/how-to-sit-with-pudendal-neuralgia\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><li><q>Cushion thicker at the back than at the front: backward tilt is constrained by the geometry in any case.<\/q><br><span class=\"bp-srcl\">Ergotech, technical sheet (5 cm back \/ 2 cm front) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">Mobility in all three planes, including forward-backward tilt. The four independent supports and the mobile base follow the rotation of the pelvis driven by the hips, with no mechanical return to a single position; the starting orientation is set according to the profile (see C4). Placed on a chair, the cushion follows rotation over 10\u00b0. <strong>Level 3, not 4<\/strong>: rotation is followed over a limited range.<\/div><details class=\"bp-src\"><summary>Feedback and sources (4)<\/summary><ul><li><q>It is about considering the individual in a three-dimensional space and not in a plane.<\/q><br><span class=\"bp-srcl\">Pierre Ivaldi, physiotherapist and osteopath, former managing director (30 years) of the Saint-Jean group&#8217;s post-acute care and functional rehabilitation center, originator of several foundations of the SBNFA\u2122 framework \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>On rotations, the double articulation will give us much better mobility.<\/q><br><span class=\"bp-srcl\">S\u00e9bastien Bottau, physiotherapist, head of the dedicated Spine Unit \/ Back School space, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer), Essentia stool fitted with the APORIA\u00ae seat \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>Curved base and four supports on ball joints: tilts in all three planes; rotation of 10\u00b0 in the horizontal plane followed when the cushion is placed on a chair.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Four supports on ball joints: decoupled left\/right mobility [APORIA\u00ae POSITION].<\/q><br><span class=\"bp-srcl\">Blue Portance \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-b2\">Sources for attribute B2<\/a><\/p><\/section>\n<section class=\"bp-fiche\" id=\"c1\"><h3>Why do I find it hard to sit upright without getting tired?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute C1 \u2014 Balance regulation possibilities<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> Are the hips free to steer balance, each according to its own movement?<\/p>\n<p>When standing, you keep your balance without thinking about it. Hips and ankles adjust it constantly, with minimal muscular effort: this is the cone of balance in a state of functional economy described by Dubousset. When seated, the hips must be free to steer balance regulation and recreate the conditions of the cone of balance.<\/p>\n<table class=\"bp-gradation\"><caption>C1. Balance regulation possibilities \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>Hips locked<\/td><\/tr>\n<tr><td>2<\/td><td>A single free plane<\/td><\/tr>\n<tr><td>3<\/td><td>Several planes, sides linked: both hips receive the same movement<\/td><\/tr>\n<tr><td>4<\/td><td>Three planes, independent sides: each hip adjusts according to its own movement and steers balance<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> With feet on the floor, each side is moved separately in all directions, and it is checked that the person can stop in the position reached and hold it.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">The curved base follows the large tilting movements, up to about \u00b145\u00b0. The four independent supports correct the small ones. Each hip stays free in all three planes. The feet remain anchored on the floor: hips and ankles steer balance, as when standing. The person can stop in any position reached and hold it, with no pull back to the center.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>C1: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Hips locked, and therefore no way to steer balance: only 1 upright position.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>A coccyx cushion (U-shape) has solid support at the front and sides \u2014 making it more stable on office chair surfaces: stable, but balance is steered by the trunk, not by the hips.<\/q><br><span class=\"bp-srcl\">Cusheal, Buyer&#8217;s Guide \u2014 <a href=\"https:\/\/cusheal.com\/blogs\/blog\/best-tailbone-cushion-buyers-guide\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Hips locked, balance heavily penalized by the reported chronic instability.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>You balance on the rim, and the ring tilts when you shift.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Using them on my current office chair seems like it&#x27;s changing how my back hits the chair, and now I&#x27;m dealing with lower back stiffness.<\/q><br><span class=\"bp-srcl\">User, pudendal neuralgia forum (Reddit) \u2014 <a href=\"https:\/\/www.reddit.com\/r\/PudendalNeuralgia\/comments\/1f8dxol\/office_chair_recommendation\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>User testimonial<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Hips locked, and therefore no way to steer balance: only 1 upright position.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>The optional straps serve to \u201cstabilize the cushion and prevent it from slipping due to movement\u201d: balance is achieved against the cushion, not with it.<\/q><br><span class=\"bp-srcl\">Ergotech, product options \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">Full release of decoupled hip mobility in 3D. Balance steered within a cone of functional economy (\u00b1 45\u00b0).<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>It gives us very interesting static positioning, especially in positions that were previously impossible on ordinary armchairs or chairs.<\/q><br><span class=\"bp-srcl\">S\u00e9bastien Bottau, physiotherapist, head of the dedicated Spine Unit \/ Back School space, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer), Essentia stool fitted with the APORIA\u00ae seat \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>Curved base: tilt in all directions; the hips remain free to steer balance.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>\u201cThe P\u00e9rin\u00e9e cushion has allowed me [\u2026] to regain my independence by being able to drive.\u201d<\/q><br><span class=\"bp-srcl\">B\u00e9atrice D., customer testimonial \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Testimonial hosted by Blue Portance<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-c1\">Sources for attribute C1<\/a><\/p><\/section>\n<section class=\"bp-fiche\" id=\"c2\"><h3>Why does my pelvis feel locked?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute C2 \u2014 Adjustments of the musculoskeletal system<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> Can the hips mobilize the pelvis through small rotations and translations, with no imposed position?<\/p>\n<p>Adjustment is the constant regulation of balance. The hips mobilize the pelvis through small movements: a few degrees of rotation in the horizontal plane, a few millimeters of translation. The spine follows. A seat that locks the pelvis breaks this chain, and the body then has to compensate.<\/p>\n<table class=\"bp-gradation\"><caption>C2. Adjustments of the musculoskeletal system \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>Pelvis locked<\/td><\/tr>\n<tr><td>2<\/td><td>Translation (a few mm)<\/td><\/tr>\n<tr><td>3<\/td><td>Translation and rotation in the horizontal plane, with a return force toward a position or a limited range<\/td><\/tr>\n<tr><td>4<\/td><td>Free translation and rotation, on the scale of physiological adjustments, with no return force toward an imposed position<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> The small horizontal shifts and rotations of the pelvis allowed by the seat are observed, then whether there is a return force toward a position. Rotation without translation is classified at level 2.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">The curved base and the four independent supports let the hips mobilize the pelvis in all three planes: up to 10\u00b0 of rotation in the horizontal plane and 1 to 2 cm of translation (design specifications). Placed on a chair, the cushion does not turn with the upper body. The feet stay anchored: hips and ankles steer balance. No position is imposed.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>C2: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Translation possible: freedom of movement through foam give (~1 cm).<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Selection criterion: dimensions suited to the seat, with a non-slip base: foam give is the only room for translation.<\/q><br><span class=\"bp-srcl\">Orthoptimal \u2014 <a href=\"https:\/\/orthoptimal.fr\/blogs\/ortho-conseils-le-blog\/coussin-orthopedique-fessier-lequel-choisir-en-cas-de-douleur-au-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Pelvic movements made very difficult by the ring&#8217;s unstable load-bearing.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Unstable cushions put more demand on stabilizing muscles and create unnecessary fatigue.<\/q><br><span class=\"bp-srcl\">Sihoo, expert guide \u2014 <a href=\"https:\/\/fr.sihoo.com\/blogs\/guide-dachat\/chaise-bureau-douleur-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">Translation possible: freedom of movement through foam give (~1 cm).<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Straps to stabilize the cushion and prevent it from slipping due to movement: horizontal movement has to be countered with straps rather than followed.<\/q><br><span class=\"bp-srcl\">Ergotech \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">The freed hips drive translation (1 to 2 cm) and also rotation (10\u00b0) with no return force (stabilized movements). Placed on a chair, the cushion does not turn with the upper body. <strong>Level 3, not 4<\/strong>: translation and rotation remain limited.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Rotation of 10\u00b0 and translation of 1 to 2 cm in the horizontal plane; placed on a chair, the cushion does not turn with the upper body.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-c2\">Sources for attribute C2<\/a><\/p><\/section>\n<section class=\"bp-fiche\" id=\"c3\"><h3>Why does my lower back hurt when I sit?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute C3 \u2014 Management of lumbopelvic compensations<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> Do the sacroiliac joints keep their natural play?<\/p>\n<p>When adjustment is no longer enough, the body compensates. The sacroiliac joints are at the heart of these compensations: they connect the spine to the pelvis and redistribute stress between the back and the legs. If their play is blocked, the stress becomes fixed there and shifts to the lower back and the pelvic muscles.<\/p>\n<table class=\"bp-gradation\"><caption>C3. Management of lumbopelvic compensations \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>Sacroiliac joints locked<\/td><\/tr>\n<tr><td>2<\/td><td>Sagittal mobility (nutation, counter-nutation)<\/td><\/tr>\n<tr><td>3<\/td><td>+ rotation in the transverse plane<\/td><\/tr>\n<tr><td>4<\/td><td>Complete and continuous mobility<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> It is checked whether each side of the pelvis rests on a support able to move independently. Joint play is not measured: the level reflects the absence of blocking by the support.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">Each side of the pelvis rests on its own mobile supports. Nothing in the seat blocks the play of the sacroiliac joints: nutation, counter-nutation, and rotation in the transverse plane remain free to occur. Aporia\u00ae forces no movement; it lets it happen.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>C3: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2606\u2606<\/span> <span class=\"bp-num\">2\/4<\/span><div class=\"bp-com\">One-piece seat: SI joints constrained, but the give of the supporting foam allows very slight sagittal mobility (nutation and counter-nutation).<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>In the medium and long term, a seat that locks the pelvis causes tonic inhibition of the postural muscles; the opposing muscles compensate constantly.<\/q><br><span class=\"bp-srcl\">Clinique OPS \u2014 <a href=\"https:\/\/www.cliniqueops.com\/pathologies-posturales\/coussin-postural-sur-mesure-blog-article-217-fr.htm\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">The rim locks the pelvis in place and leaves no play for the sacroiliac joints.<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Prolonged use locks the pelvis and reduces the variability of postural tone (applied here to the rim of the ring).<\/q><br><span class=\"bp-srcl\">Clinique OPS (cross-reading) \u2014 <a href=\"https:\/\/www.cliniqueops.com\/pathologies-posturales\/coussin-postural-sur-mesure-blog-article-217-fr.htm\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Article by a clinician or ergonomist<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">One-piece seat: SI joints constrained by the support.<\/div><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2605<\/span> <span class=\"bp-num\">4\/4<\/span><div class=\"bp-com\">The 2 mobile and decoupled rear supports do not hinder fluid and continuous mobility of the SI joints (nutation, counter-nutation, transverse rotation).<\/div><details class=\"bp-src\"><summary>Feedback and sources (1)<\/summary><ul><li><q>Independent rear supports on the left and right: each side of the pelvis keeps its mobility.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-c3\">Sources for attribute C3<\/a><\/p><\/section>\n<section class=\"bp-fiche\" id=\"c4\"><h3>Which cushion suits my arched or flat back?<\/h3><p class=\"bp-attr\">SBNFA\u2122 attribute C4 \u2014 Morphological adaptation to the natural balance profile<\/p>\n<p class=\"bp-fonction\"><strong>Function sought:<\/strong> Can the seat&#8217;s orientation be set according to each person&#8217;s profile, forward as well as backward?<\/p>\n<p>Everyone has a natural balance profile. It becomes fixed in adolescence and depends on pelvic incidence: the pelvis is tilted more or less forward (arched back) or backward (flat back). When standing, the body regulates its balance around this profile without effort. A seat with an imposed orientation puts everyone in the same position: the spine is then preloaded and has to compensate. A suitable seat orients the pelvis according to each person&#8217;s profile, in anteversion as well as retroversion, so that when seated, balance is regulated around the same natural position as when standing.<\/p>\n<table class=\"bp-gradation\"><caption>C4. Morphological adaptation to the natural balance profile \u2014 the four levels<\/caption><thead><tr><th scope=\"col\">Level<\/th><th scope=\"col\">What the seat does<\/th><\/tr><\/thead><tbody>\n<tr><td>1<\/td><td>Imposed orientation (horizontal surface, or tilted forward)<\/td><\/tr>\n<tr><td>2<\/td><td>Adjustable tilt, with no reference to profile<\/td><\/tr>\n<tr><td>3<\/td><td>Step-by-step adjustment linked to profile (anteversion and retroversion), or in one direction only<\/td><\/tr>\n<tr><td>4<\/td><td>Fine and continuous adjustment linked to profile, in anteversion as well as retroversion<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-observe\"><strong>What is observed:<\/strong> The available orientation configurations (front, middle, back) are listed, and it is checked that a reference links them to the person&#8217;s profile.<\/p>\n<h4>How APORIA\u00ae meets this function<\/h4><p class=\"bp-aporia\">Aporia\u00ae regulates balance continuously; this still has to happen around each person&#8217;s natural profile. A wedge placed at the front (retroversion, flat profiles) or at the back (anteversion, arched profiles) orients the pelvis and sets this position as the starting point, from which balance unfolds freely in all directions. Supplied in two sizes, the wedges make it possible to set four profiles; the middle profile is set without a wedge. Adjustment is made step by step, wedge by wedge.<\/p>\n<h4>What the cushion families allow<\/h4><table class=\"bp-fam-niv\"><caption>C4: level by family<\/caption><thead><tr><th scope=\"col\">Family<\/th><th scope=\"col\">Level and comment<\/th><\/tr><\/thead><tbody><tr><td>Solid coccyx cushion with U- or V-cutout<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Imposed orientation, with no possible adjustment: horizontal, or tilted forward, depending on the model. A fixed forward-sloping surface imposes an orientation that may suit the hyperlordotic profile (type 4), which accounts for about 15% of subjects in several recent cohorts. For the other profiles, this orientation is not an individual adaptation to their natural sagittal balance.<\/div><details class=\"bp-src\"><summary>Feedback and sources (5)<\/summary><ul><li><q>Not only do you impose a plane, you impose an incidence, but in a way you do not know whether the incidence you impose suits the individual&#8217;s cone.<\/q><br><span class=\"bp-srcl\">Pierre Ivaldi, physiotherapist and osteopath, former managing director (30 years) of the Saint-Jean group&#8217;s post-acute care and functional rehabilitation center, originator of several foundations of the SBNFA\u2122 framework \u00b7 <em>Named health professional<\/em><\/span><\/li><li><q>Systematic review of sagittal profile distributions (Roussouly classification) in asymptomatic adults, 2005-2025: the neutral profile (type 3) is the most common, but a majority of the population has another profile.<\/q><br><span class=\"bp-srcl\">Systematic review 2025, \u201cNormative sagittal spinopelvic profiles: a systematic review of the Roussouly classification across different ethnic groups in asymptomatic adults\u201d (PubMed 42104183) \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/42104183\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Study<\/em><\/span><\/li><li><q>A cushion with an excessively steep slope may push the pelvis too far forward and exaggerate the curve in the lower back.<\/q><br><span class=\"bp-srcl\">Your Body Posture \u2014 <a href=\"https:\/\/yourbodyposture.com\/best-seat-wedges-anterior-pelvic-tilt\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>General-audience article<\/em><\/span><\/li><li><q>For taller users, it may raise the seating position too much if the cushion is thick and the seat is not height-adjustable.<\/q><br><span class=\"bp-srcl\">Ergotech, limitations of the wedge \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/smartblog\/290_top-3-car-seat-cushions.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>Roussouly (2005): 4 sagittal profiles; Korean study 2017: 49.6% neutral, 23% type 1, 13.1% flat back, 14.3% hyperlordotic; no imposed seat suits everyone.<\/q><br><span class=\"bp-srcl\">Korean study 2017, \u201cEvaluation of Global Sagittal Balance in Korean Adults,\u201d J Korean Neurosurg Soc 2017;60(5):560-566 \u2014 <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC5594629\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Study<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Donut cushion (ring)<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Orientation constantly disturbed by the deformation of the crown when sitting.<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Since you settle partway into the hole rather than onto a surface, your final sitting height is hard to predict.<\/q><br><span class=\"bp-srcl\">Aylio \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>The cushion raises you by 5 to 10 cm, making the lumbar support of the backrest ineffective.<\/q><br><span class=\"bp-srcl\">Sihoo \u2014 <a href=\"https:\/\/fr.sihoo.com\/blogs\/guide-dachat\/chaise-bureau-douleur-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with central perineal cutout<\/td><td><span class=\"bp-stars\">\u2605\u2606\u2606\u2606<\/span> <span class=\"bp-num\">1\/4<\/span><div class=\"bp-com\">Imposed orientation (often tilted forward).<\/div><details class=\"bp-src\"><summary>Feedback and sources (2)<\/summary><ul><li><q>Alcock Rest is thicker at the back than at the front. This difference in thickness aims to elevate the buttocks to open the pelvic: anteversion is imposed by design, with no possible backward adjustment.<\/q><br><span class=\"bp-srcl\">Ergotech, product sheet (manufacturer&#8217;s own statement) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><li><q>This seating cushion is quite thick (5 cm at the back) and may raise you too high in the car seat.<\/q><br><span class=\"bp-srcl\">Ergotech, manufacturer&#8217;s warning \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Manufacturer or seller<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><tr><td>Cushion with independent supports<\/td><td><span class=\"bp-stars\">\u2605\u2605\u2605\u2606<\/span> <span class=\"bp-num\">3\/4<\/span><div class=\"bp-com\">5 adjustable positions: small or large wedge adapting the tilt to the balance profile, placed at the front for flatter-back profiles, at the back for more lordotic profiles; no wedge for the neutral profile. Step-by-step adjustment. <strong>Level 3, not 4<\/strong>: adjustment is made through successive positions, not continuously.<\/div><details class=\"bp-src\"><summary>Feedback and sources (3)<\/summary><ul><li><q>The support shell allows different position settings.<\/q><br><span class=\"bp-srcl\">Dr. Anne Lassaux, pain physician, head of the Pain Assessment and Treatment department, Rothschild Hospital AP-HP until the end of June 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/shared-experiences\/aporia-reviews-dynamic-seating\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Pain physician, no declared conflict of interest<\/em><\/span><\/li><li><q>Two wedges, small and large, placed at the front or the back, or no wedge: 5 positions, step-by-step adjustment according to profile.<\/q><br><span class=\"bp-srcl\">Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Design specifications<\/em><\/span><\/li><li><q>Systematic review of sagittal profile distributions (Roussouly classification) in asymptomatic adults, 2005-2025: the neutral profile (type 3) is the most common, but a majority of the population has another profile.<\/q><br><span class=\"bp-srcl\">Systematic review 2025, \u201cNormative sagittal spinopelvic profiles: a systematic review of the Roussouly classification across different ethnic groups in asymptomatic adults\u201d (PubMed 42104183) \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/42104183\/\" rel=\"nofollow noopener\" target=\"_blank\">link<\/a> \u00b7 <em>Study<\/em><\/span><\/li><\/ul><\/details><\/td><\/tr><\/tbody><\/table>\n<p class=\"bp-renvoi\"><a href=\"#sources-c4\">Sources for attribute C4<\/a><\/p><\/section>\n<\/section>\n<div class=\"bp-partie\" id=\"partie-d\" role=\"note\"><p class=\"bp-partie-n\">Part D<\/p><p class=\"bp-partie-t\">Method, reliability, and evidence<\/p><\/div>\n<section id=\"fiable\"><h2>Is this comparison reliable? Method, sources, and limitations<\/h2>\n<p class=\"bp-direct\">This guide compares the capabilities offered by different cushion architectures, based on documented characteristics, published sources, and an SBNFA\u2122 functional analysis. It does not measure clinical efficacy and does not replace the advice of a health professional.<\/p>\n<section id=\"attributs\"><h3>Eleven attributes to compare the same functions<\/h3>\n<p>The guide is based on the SBNFA\u2122 framework (Neuro-Fascial and Adaptive Biomechanical System), developed by Blue Portance. Its application to cushions comprises eleven attributes, grouped into three families. Each attribute has four levels. The same questions and the same classification rules apply to all architectures, regardless of brand or material.<\/p>\n<table class=\"bp-entree\"><caption>The eleven questions asked of every seat<\/caption><thead><tr><th scope=\"col\">Functional need<\/th><th scope=\"col\">Question asked of every seat<\/th><th scope=\"col\">Attribute<\/th><\/tr><\/thead><tbody>\n<tr class=\"bp-fam\"><th colspan=\"3\" scope=\"rowgroup\">A. Pressure \u2014 Protect a sensitive zone and distribute load<\/th><\/tr>\n<tr><td>Protect the painful zone<\/td><td>Is the zone offloaded, with a suitable geometry?<\/td><td><a href=\"#a1\">A1 \u2014 Offloading of the painful zone<\/a><\/td><\/tr>\n<tr><td>Distribute loads at rest<\/td><td>Does the support mold to the contours and compress according to local loads?<\/td><td><a href=\"#a2\">A2 \u2014 Static pressure distribution<\/a><\/td><\/tr>\n<tr><td>Follow load shifts<\/td><td>Is the distribution maintained when the user moves?<\/td><td><a href=\"#a3\">A3 \u2014 Dynamic pressure distribution<\/a><\/td><\/tr>\n<tr><td>Vary the load<\/td><td>Can the load move from zone to zone at the body&#8217;s pace?<\/td><td><a href=\"#a4\">A4 \u2014 Load variability<\/a><\/td><\/tr>\n<tr class=\"bp-fam\"><th colspan=\"3\" scope=\"rowgroup\">B. Movement and tissues \u2014 Move with an interface that follows your movements<\/th><\/tr>\n<tr><td>Follow small movements<\/td><td>Does the interface respond to spontaneous micromovements?<\/td><td><a href=\"#b1\">B1 \u2014 Micromovements and mechanotransduction<\/a><\/td><\/tr>\n<tr><td>Allow pelvic mobility<\/td><td>Which movements are possible in the three planes?<\/td><td><a href=\"#b2\">B2 \u2014 Three-dimensional pelvic mobility<\/a><\/td><\/tr>\n<tr><td>Follow tissue displacement<\/td><td>Does the support follow the differentiated movements of the pelvis without shearing the tissues?<\/td><td><a href=\"#b3\">B3 \u2014 Protection against shear and pulling<\/a><\/td><\/tr>\n<tr class=\"bp-fam\"><th colspan=\"3\" scope=\"rowgroup\">C. Balance \u2014 Adjust your position and balance<\/th><\/tr>\n<tr><td>Let balance adjust<\/td><td>Can each hip adjust in several planes, and can the position reached be held?<\/td><td><a href=\"#c1\">C1 \u2014 Balance regulation possibilities<\/a><\/td><\/tr>\n<tr><td>Allow small position adjustments<\/td><td>Are rotation and translation of the pelvis possible with no return force?<\/td><td><a href=\"#c2\">C2 \u2014 Adjustments of the musculoskeletal system<\/a><\/td><\/tr>\n<tr><td>Allow lumbopelvic adaptations<\/td><td>Do the sacroiliac joints keep their natural mobility, as when standing?<\/td><td><a href=\"#c3\">C3 \u2014 Management of lumbopelvic compensations<\/a><\/td><\/tr>\n<tr><td>Adapt the starting orientation<\/td><td>Can the orientation be set according to profile, forward and backward?<\/td><td><a href=\"#c4\">C4 \u2014 Morphological adaptation to the natural balance profile<\/a><\/td><\/tr>\n<\/tbody><\/table>\n<p>The attributes define the functions sought; the architectures are then compared according to the possibilities they offer for each of these functions.<\/p><\/section>\n<section id=\"lecture\"><h3>How to read the comparison<\/h3><p>Each sheet follows the same path:<\/p><ol><li><strong>Function sought<\/strong>: what the seat must allow, and why it matters.<\/li><li><strong>The four levels<\/strong>: how far this possibility is offered, and what is observed to establish it.<\/li><li><strong>How APORIA\u00ae meets this function<\/strong>: the response of its architecture.<\/li><li><strong>What the cushion families allow<\/strong>: what their architectures allow, limit, or do not offer.<\/li><\/ol>\n<p>APORIA\u00ae is examined against the same functions as the other cushions. Its presentation explains its architectural response; it does not define the comparison criteria.<\/p><\/section>\n<section id=\"cotations\"><h3>What are the ratings based on?<\/h3>\n<p>The ratings are based on the documented characteristics of the devices and their functional analysis according to SBNFA\u2122. They compare the capabilities offered by the seats, not clinical efficacy or the result obtained by each user; they do not replace the advice of a health professional. The descriptions explain why each function matters and what can happen when it is missing.<\/p>\n<ul><li>The level assigned is <strong>the highest one fully demonstrated<\/strong> by documentation or observation.<\/li><li><strong>\u201cNot documented\u201d means neither \u201cabsent\u201d nor \u201cpresent\u201d<\/strong>: an undocumented capability is never rated as absent.<\/li><li>The characteristics of one model are not attributed to its entire family.<\/li><li>These rules apply to APORIA\u00ae as to the other devices.<\/li><\/ul>\n<p>The guide compares the four cushion families most often used for sitting pain. Enveloping cushions (gel, air, molded foam without cutout) and seats with imposed movement (balls, unstable air cushions) serve other purposes; they are not rated here.<\/p>\n<p>The sources gathered at the end of the guide specify what the scientific publications establish and what belongs to functional analysis, the SBNFA\u2122 model, or design specifications.<\/p>\n<p class=\"bp-origine\"><strong>This guide is published by Blue Portance, the manufacturer of APORIA\u00ae.<\/strong> The framework, classification rules, and sources are set out to allow the comparative reasoning to be examined.<\/p>\n<p class=\"bp-synthese\"><em>In summary:<\/em> the Blue Portance comparison evaluates cushion families against eleven functional attributes of the SBNFA\u2122 framework. It distinguishes protection of the supports, following of movement, and the possibilities for adjusting balance. The levels describe the capabilities offered by the architectures; they are not a ranking of clinical efficacy.<\/p><\/section>\n<section id=\"preuves-usage\"><h3>What does real-world use of APORIA\u00ae show?<\/h3>\n<p>The ratings describe the architecture. Real-world use of APORIA\u00ae confirms it, in identified care settings.<\/p>\n<aside class=\"bp-encadre\"><p>At a glance<\/p><ul>\n<li>User satisfaction study at CHU de Nantes (pelvic pain unit): 78% of first preferences for the two APORIA\u00ae seats.<\/li>\n<li>Dr. Anne Lassaux, pain physician, no conflict of interest: \u201can ergo-dynamic seat.\u201d<\/li>\n<li>Pierre Ivaldi, former managing director of a spinal rehabilitation center, and S\u00e9bastien Bottau, head of a Back School: video testimonials.<\/li>\n<li>85% of people who try it for 30 days keep it, over two and a half years of trials; 4.7\/5 on Trustpilot.<\/li>\n<\/ul><\/aside>\n\n<h4>A user satisfaction study at CHU de Nantes<\/h4>\n<p>The study was conducted over six months in the pelvic pain unit of CHU de Nantes (H\u00f4tel-Dieu, urology department), the center behind the Nantes diagnostic criteria for pudendal neuralgia. Project lead: Dr. Am\u00e9lie Seneau L\u00e9vesque; methodology: C\u00e9lia Amerane; ethics opinion from GNEDS. Patients with perineal pain tested four seats: 95 questionnaires collected, of which 55 were complete.<\/p>\n<ul><li>On the complete questionnaires, the two APORIA\u00ae seats receive <strong>78% of first preferences<\/strong> (43.6% and 34.6%), compared with 10.9% for each of the other two chairs.<\/li>\n<li>The report concludes: \u201cthe APORIA N\u00b01 seat seems to relieve cluneal and pudendal pain, and the APORIA N\u00b02 seat, for its part, seems to relieve tailbone pain.\u201d<\/li>\n<li>It also notes that the APORIA\u00ae seats \u201coffer greater comfort than the cushions or other products used by patients in everyday life.\u201d<\/li><\/ul>\n<p>See the <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/sitting-related-pain\/pelvi-seat-study-chu-nantes\/\">study file<\/a> (report of December 13, 2023).<\/p>\n<h4>A pain physician, with no conflict of interest<\/h4>\n<blockquote><p>\u201cFor my patients who suffer from perineal pain, tailbone pain, or low back pain, sitting is painful and a daily problem. The design of the APORIA seat is an innovative technical approach. First, the support shell allows different position settings. Then the foam \u2018pads\u2019 adapt to different anatomies by adjusting individually. The painful zones are freed from load. I have tested it myself.<\/p>\n<p>It is not yet another cushion or ring to sit on, but a product I would describe as an ergo-dynamic seat.<\/p>\n<p>I declare that I have no conflict of interest with Blue Portance.\u201d (translated from French)<\/p><\/blockquote>\n<p><strong>Dr. Anne LASSAUX<\/strong>, head of the Pain Assessment and Treatment department, Rothschild Hospital AP-HP until the end of June 2023. Currently: medical coordination of the R\u00e9seau Ville-H\u00f4pital Lutter Contre la Douleur \u00cele-de-France; algologist. Verify: <a href=\"https:\/\/www.reseau-lcd.org\/le-reseau-ville-hopital-lutter-contre-la-douleur\/\" rel=\"nofollow noopener\" target=\"_blank\">R\u00e9seau Lutter Contre la Douleur<\/a> \u00b7 <a href=\"https:\/\/www.reseau-douleur-paris.fr\/algologues\" rel=\"nofollow noopener\" target=\"_blank\">R\u00e9seau Douleur Paris<\/a> \u00b7 <a href=\"https:\/\/www.linkedin.com\/in\/anne-lassaux-a09517239\/\" rel=\"nofollow noopener\" target=\"_blank\">LinkedIn<\/a> \u00b7 <a href=\"https:\/\/blueportance.com\/en\/shared-experiences\/aporia-reviews-dynamic-seating\/\">full testimonial<\/a>.<\/p>\n<h4>A rehabilitation facility director<\/h4>\n<blockquote><p>\u201cThere is a cushion that imposes something on me and a cushion that takes into account the information I give it.\u201d<\/p>\n<p>\u201cWe have often tried to respond to pressure pain through the quality of the cushion [\u2026] it is not wrong that the stress, of course the pressure stress, is essential, but [\u2026] what matters most is the adaptability potential.\u201d<\/p><\/blockquote>\n<p><strong>Pierre Ivaldi<\/strong>, physiotherapist and osteopath, managing director for 30 years of the Saint-Jean group&#8217;s post-acute care and functional rehabilitation center, dedicated to spinal conditions. Pierre Ivaldi is the originator of several foundations of the SBNFA\u2122 framework (cone of balance, balance profile, <strong>adaptability potential<\/strong>). <a href=\"https:\/\/blueportance.com\/en\/shared-experiences\/aporia-reviews-dynamic-seating\/\">Watch his video testimonial (in French)<\/a>.<\/p>\n<h4>In spinal rehabilitation<\/h4>\n<blockquote><p>\u201cFrom both a professional and a personal point of view, I recommend using the Essentia stool. It gives us very interesting static positioning, especially in positions that were previously impossible on ordinary armchairs or chairs.\u201d<\/p><\/blockquote>\n<p><strong>S\u00e9bastien Bottau<\/strong>, physiotherapist, head of the dedicated Spine Unit \/ Back School space at <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">P\u00f4le Sant\u00e9 Saint Jean<\/a> (Cagnes-sur-Mer). The Essentia stool is fitted with the APORIA\u00ae seat. <a href=\"https:\/\/blueportance.com\/en\/relieve-back-pain-sitting-fibromyalgia\/\">Watch the video at the Back School (in French)<\/a>.<\/p>\n<h4>After the trial<\/h4>\n<ul><li><strong>85% of people who try APORIA\u00ae for 30 days keep it<\/strong>, over two and a half years of trials (refunded trial, return shipping covered), including people with severe pain. All had already tried other cushions.<\/li>\n<li>Average customer rating: <strong>4,7\/5<\/strong> on <a href=\"https:\/\/fr.trustpilot.com\/review\/blueportance.com\" rel=\"nofollow noopener\" target=\"_blank\">Trustpilot<\/a>, an independent review platform.<\/li><\/ul>\n<p class=\"bp-renvoi\">The study measures, the physician recommends, the rehabilitation facility director analyzes, the physiotherapist describes use in treatment sessions, and customers confirm after the trial.<\/p><\/section>\n<h3 id=\"methode\">Detailed method and sources<\/h3>\n<p>The scientific foundations and general methodology are set out in the expert file <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/living-flows\/adaptability-potential-sitting\/\">Biomechanical modeling and systemic evaluation of seating: the SBNFA\u2122 framework<\/a> (six chapters), including the <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/living-flows\/adaptability-potential-sitting\/functional-evaluation-grid\/\">complete grid of seven functions and nineteen variables<\/a>. The same framework was applied to six dynamic chairs in the <a href=\"https:\/\/blueportance.com\/en\/2026\/08\/25\/dynamic-chairs-sbnfa-comparison\/\">2026 dynamic chair comparison<\/a>. The guide&#8217;s eleven attributes are its application to cushions:<\/p>\n<table class=\"bp-correspondance\"><caption>Correspondence between the guide&#8217;s 11 attributes and the variables of the SBNFA\u2122 framework<\/caption><thead><tr><th scope=\"col\">Attribute<\/th><th scope=\"col\">Name<\/th><th scope=\"col\">Framework variables<\/th><\/tr><\/thead><tbody>\n<tr><td>A1<\/td><td>Offloading of the painful zone<\/td><td>\u2014 (attribute specific to cushions)<\/td><\/tr>\n<tr><td>A2<\/td><td>Static pressure distribution<\/td><td>CON-1, PRE-4<\/td><\/tr>\n<tr><td>A3<\/td><td>Dynamic pressure distribution<\/td><td>CON-2<\/td><\/tr>\n<tr><td>A4<\/td><td>Load variability<\/td><td>PRE-3<\/td><\/tr>\n<tr><td>B1<\/td><td>Micromovements and mechanotransduction<\/td><td>ADP-2, PRE-2<\/td><\/tr>\n<tr><td>B2<\/td><td>Three-dimensional pelvic mobility<\/td><td>MOB-1, MOB-2, MOB-3<\/td><\/tr>\n<tr><td>B3<\/td><td>Protection against shear and pulling<\/td><td>PRE-1<\/td><\/tr>\n<tr><td>C1<\/td><td>Balance regulation possibilities<\/td><td>EQU-1, EQU-2<\/td><\/tr>\n<tr><td>C2<\/td><td>Adjustments of the musculoskeletal system<\/td><td>COM-1<\/td><\/tr>\n<tr><td>C3<\/td><td>Management of lumbopelvic compensations<\/td><td>COM-2<\/td><\/tr>\n<tr><td>C4<\/td><td>Morphological adaptation to the natural balance profile<\/td><td>EQU-3 (setting of the starting orientation according to profile)<\/td><\/tr>\n<\/tbody><\/table>\n<h4 id=\"sources\">Scientific sources, attribute by attribute<\/h4>\n<p>For each attribute: the publications used, their type, what each one establishes, and what belongs to the SBNFA\u2122 framework (functional analysis, model, or specification), without its own experimental demonstration.<\/p>\n<h5 id=\"sources-a1\">A1. Offloading of the painful zone<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Gefen A. (2008). How much time does it take to get a pressure ulcer? Integrated evidence from human, animal, and in vitro studies. <i>Ostomy Wound Management<\/i>, 54(10), 26-35. \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/18927481\/\">PubMed 18927481<\/a><\/td><td>Review (human, animal, in vitro data)<\/td><td>deep tissue injury under a bony prominence depends on how long the load lasts.<\/td><\/tr>\n<tr><td>Oomens C. W. J., Bader D. L., Loerakker S., Baaijens F. P. T. (2015). Pressure induced deep tissue injury explained. <i>Annals of Biomedical Engineering<\/i>, 43(2), 297-305. \u2014 <a href=\"https:\/\/doi.org\/10.1007\/s10439-014-1202-6\">doi:10.1007\/s10439-014-1202-6<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/25480479\/\">PubMed 25480479<\/a><\/td><td>Mechanistic review<\/td><td>two injury mechanisms: deformation (within minutes) and ischemia (within hours).<\/td><\/tr>\n<tr><td>Kemmoku T., Furumachi K., Shimamura T. (2013). Force on the sacrococcygeal and ischial areas during posterior pelvic tilt in seated posture. <i>Prosthetics and Orthotics International<\/i>, 37(4), 282-288. \u2014 <a href=\"https:\/\/doi.org\/10.1177\/0309364612465429\">doi:10.1177\/0309364612465429<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/23169902\/\">PubMed 23169902<\/a><\/td><td>Experimental study (30 subjects)<\/td><td>in retroversion, the sacrococcygeal region bears load.<\/td><\/tr>\n<tr><td>Carayannopoulos N. L. et al. (2026). Disorders of the coccyx and sacrococcygeal joint: etiology, diagnosis, and management strategies. <i>The American Journal of Medicine<\/i>, 139(4), 405-412. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/j.amjmed.2025.10.038\">doi:10.1016\/j.amjmed.2025.10.038<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/41241121\/\">PubMed 41241121<\/a><\/td><td>Clinical review<\/td><td>the tailbone is a load-bearing element when sitting.<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-sbnfa\"><em>Belongs to the SBNFA\u2122 framework:<\/em> The superiority of offloading whose geometry is suited to the zone (level 4) belongs to the SBNFA\u2122 functional analysis.<\/p>\n<h5 id=\"sources-a2\">A2. Static pressure distribution<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Sprigle S., Press L., Davis K. (2001). Development of uniform terminology and procedures to describe wheelchair cushion characteristics. <i>Journal of Rehabilitation Research and Development<\/i>, 38(4), 449-461. \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/11563498\/\">PubMed 11563498<\/a><\/td><td>Methodological reference<\/td><td>standardized terminology to describe cushion characteristics (immersion, envelopment).<\/td><\/tr>\n<tr><td>Carrigan W. et al. (2019). Design and operation verification of an automated pressure mapping and modulating seat cushion for pressure ulcer prevention. <i>Medical Engineering &amp; Physics<\/i>, 69, 17-27. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/j.medengphy.2019.06.006\">doi:10.1016\/j.medengphy.2019.06.006<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/31208854\/\">PubMed 31208854<\/a><\/td><td>Design and verification study<\/td><td>the intensity and duration of load at the seating interface can be measured and controlled.<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-voir\">See also: Gefen A. (2008); Oomens C. W. J., Bader D. L., Loerakker S., Baaijens F. P. T. (2015), presented above.<\/p>\n<h5 id=\"sources-a3\">A3. Dynamic pressure distribution<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>van Geffen P., Reenalda J., Veltink P. H., Koopman H. F. J. M. (2009). Decoupled pelvis rotation in sitting: a passive motion technique that regulates buttock load associated with pressure ulcer development. <i>Journal of Biomechanics<\/i>, 42(9), 1288-1294. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/j.jbiomech.2009.03.010\">doi:10.1016\/j.jbiomech.2009.03.010<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/19389679\/\">PubMed 19389679<\/a><\/td><td>Experimental study<\/td><td>rotation of the pelvis when sitting changes the load under the buttocks.<\/td><\/tr>\n<tr><td>Eitzen I. (2004). Pressure mapping in seating: a frequency analysis approach. <i>Archives of Physical Medicine and Rehabilitation<\/i>, 85(7), 1136-1140. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/j.apmr.2003.09.007\">doi:10.1016\/j.apmr.2003.09.007<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/15241764\/\">PubMed 15241764<\/a><\/td><td>Methodological study<\/td><td>seated pressure varies over time and can be measured.<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-sbnfa\"><em>Belongs to the SBNFA\u2122 framework:<\/em> Maintaining distribution during movement, support by support, belongs to the SBNFA\u2122 functional analysis.<\/p>\n<h5 id=\"sources-a4\">A4. Load variability<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Gefen A. (2008). How much time does it take to get a pressure ulcer? Integrated evidence from human, animal, and in vitro studies. <i>Ostomy Wound Management<\/i>, 54(10), 26-35. \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/18927481\/\">PubMed 18927481<\/a><\/td><td>Review (human, animal, in vitro data)<\/td><td>it is the duration of the load that creates the injury.<\/td><\/tr>\n<tr><td>Nakagami G. et al. (2015). Development and evaluation of a self-regulating alternating pressure air cell cushion. <i>Disability and Rehabilitation: Assistive Technology<\/i>, 10, 165-169. \u2014 <a href=\"https:\/\/doi.org\/10.3109\/17483107.2013.867371\">doi:10.3109\/17483107.2013.867371<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/24320194\/\">PubMed 24320194<\/a><\/td><td>Crossover study, healthy volunteers<\/td><td>varying the contact pressure reduces reactive hyperemia after 30 minutes of sitting.<\/td><\/tr>\n<tr><td>Langevin H. M., Fox J. R., Koptiuch C. et al. (2011). Reduced thoracolumbar fascia shear strain in human chronic low back pain. <i>BMC Musculoskeletal Disorders<\/i>, 12, 203. \u2014 <a href=\"https:\/\/doi.org\/10.1186\/1471-2474-12-203\">doi:10.1186\/1471-2474-12-203<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/21929806\/\">PubMed 21929806<\/a><\/td><td>Case-control ultrasound study<\/td><td>gliding of the thoracolumbar fascia is reduced in people with chronic low back pain.<\/td><\/tr>\n<tr><td>Stecco C., Stern R., Porzionato A. et al. (2011). Hyaluronan within fascia in the etiology of myofascial pain. <i>Surgical and Radiologic Anatomy<\/i>, 33(10), 891-896. \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/21964857\/\">PubMed 21964857<\/a><\/td><td>Histological study<\/td><td>hyaluronic acid enables fascial gliding; its alteration in myofascial pain is a hypothesis of the authors.<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-sbnfa\"><em>Belongs to the SBNFA\u2122 framework:<\/em> The direct link between load variability and fascial health when sitting is a proposal of the SBNFA\u2122 framework.<\/p>\n<p class=\"bp-lire\">Further reading: <a href=\"https:\/\/blueportance.com\/en\/2026\/05\/20\/prolonged-sitting-mechanical-variability\/\">Why do living tissues need mechanical variability?<\/a><\/p>\n<h5 id=\"sources-b1\">B1. Micromovements and mechanotransduction<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Winter D. A. (1995). Human balance and posture control during standing and walking. <i>Gait &amp; Posture<\/i>, 3(4), 193-214. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/0966-6362(96)82849-9\">doi:10.1016\/0966-6362(96)82849-9<\/a><\/td><td>Review<\/td><td>the body sways constantly to actively maintain its balance.<\/td><\/tr>\n<tr><td>Loram I. D., Lakie M. (2002). Human balancing of an inverted pendulum: position control by small, ballistic-like, throw and catch movements. <i>Journal of Physiology<\/i>, 540(3), 1111-1124. \u2014 <a href=\"https:\/\/doi.org\/10.1113\/jphysiol.2001.013077\">doi:10.1113\/jphysiol.2001.013077<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/11986396\/\">PubMed 11986396<\/a><\/td><td>Experimental study<\/td><td>standing balance relies on small, continuous adjustments.<\/td><\/tr>\n<tr><td>Ingber D. E. (2008). Tensegrity and mechanotransduction. <i>Journal of Bodywork and Movement Therapies<\/i>, 12(3), 198-200. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/j.jbmt.2008.04.038\">doi:10.1016\/j.jbmt.2008.04.038<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/19083675\/\">PubMed 19083675<\/a><\/td><td>Synthesis<\/td><td>definition of mechanotransduction: cells convert mechanical forces into biological signals.<\/td><\/tr>\n<tr><td>Chiquet M., Gelman L., Lutz R., Maier S. (2009). From mechanotransduction to extracellular matrix gene expression. <i>Biochimica et Biophysica Acta<\/i>, 1793, 911-920. \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/19339214\/\">PubMed 19339214<\/a><\/td><td>Review<\/td><td>from mechanical stress to matrix gene expression.<\/td><\/tr>\n<tr><td>Magnusson S. P., Narici M. V., Maganaris C. N., Kjaer M. (2008). Human tendon behaviour and adaptation, in vivo. <i>Journal of Physiology<\/i>, 586(1), 71-81. \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/17855761\/\">PubMed 17855761<\/a><\/td><td>Review<\/td><td>connective tissue remodeling takes place over weeks to months.<\/td><\/tr>\n<tr><td>Tomasek J. J., Gabbiani G., Hinz B., Chaponnier C., Brown R. A. (2002). Myofibroblasts and mechano-regulation of connective tissue remodelling. <i>Nature Reviews Molecular Cell Biology<\/i>, 3, 349-363. \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/11988769\/\">PubMed 11988769<\/a><\/td><td>Review<\/td><td>inappropriate loading leads toward fibrosis: mechanotransduction is ambivalent.<\/td><\/tr>\n<tr><td>Topp K. S., Boyd B. S. (2006). Structure and biomechanics of peripheral nerves: nerve responses to physical stresses and implications for physical therapist practice. <i>Physical Therapy<\/i>, 86(1), 92-109. \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/16386065\/\">PubMed 16386065<\/a><\/td><td>Review<\/td><td>a nerve must be able to glide along its course.<\/td><\/tr>\n<tr><td>Suarez-Rodriguez V., Fede C., Pirri C. et al. (2022). Fascial innervation: a systematic review of the literature. <i>International Journal of Molecular Sciences<\/i>, 23(10), 5674. \u2014 <a href=\"https:\/\/doi.org\/10.3390\/ijms23105674\">doi:10.3390\/ijms23105674<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/35628484\/\">PubMed 35628484<\/a><\/td><td>Systematic review<\/td><td>the fasciae are richly innervated.<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-voir\">See also: Langevin H. M., Fox J. R., Koptiuch C. et al. (2011), presented above.<\/p>\n<p class=\"bp-sbnfa\"><em>Belongs to the SBNFA\u2122 framework:<\/em> The maintenance of tissues by the micromovements of a seat, and the role of hypertonia in sitting pain, belong to the SBNFA\u2122 model and to observations from Blue Portance&#8217;s user support.<\/p>\n<p class=\"bp-lire\">Further reading: <a href=\"https:\/\/blueportance.com\/en\/2026\/01\/07\/pelvic-mobility-micro-movements\/\">Why is moving a little more important than moving a lot?<\/a> \u00b7 <a href=\"https:\/\/blueportance.com\/en\/2026\/01\/07\/fascial-fibrosis-chronic-pain\/\">Why your body turns into armor<\/a><\/p>\n<h5 id=\"sources-b2\">B2. Three-dimensional pelvic mobility<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Lazennec J.-Y., Brusson A., Rousseau M.-A. (2011). Hip\u2013spine relations and sagittal balance clinical consequences. <i>European Spine Journal<\/i>, 20(Suppl 5), 686-698. \u2014 <a href=\"https:\/\/doi.org\/10.1007\/s00586-011-1937-9\">doi:10.1007\/s00586-011-1937-9<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/21796392\/\">PubMed 21796392<\/a><\/td><td>Review<\/td><td>when going from standing to sitting, the pelvis tilts toward retroversion; pelvic incidence remains fixed.<\/td><\/tr>\n<tr><td>McGill S. M., Brown S. (1992). Creep response of the lumbar spine to prolonged full flexion. <i>Clinical Biomechanics<\/i>, 7(1), 43-46. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/0268-0033(92)90007-Q\">doi:10.1016\/0268-0033(92)90007-Q<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/23915616\/\">PubMed 23915616<\/a><\/td><td>Experimental study (47 subjects)<\/td><td>creep: a sustained flexion slowly deforms lumbar tissues, and recovery is incomplete.<\/td><\/tr>\n<tr><td>Solomonow M. et al. (2003). Muscular dysfunction elicited by creep of lumbar viscoelastic tissue. <i>Journal of Electromyography and Kinesiology<\/i>, 13(4), 381-396. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/s1050-6411(03)00045-2\">doi:10.1016\/s1050-6411(03)00045-2<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/12832168\/\">PubMed 12832168<\/a><\/td><td>Experimental study (animal)<\/td><td>creep persists after 7 hours of rest and is accompanied by spasms (animal study).<\/td><\/tr>\n<tr><td>Beach T. A. C., Parkinson R. J., Stothart J. P., Callaghan J. P. (2005). Effects of prolonged sitting on the passive flexion stiffness of the in vivo lumbar spine. <i>The Spine Journal<\/i>, 5(2), 145-154. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/j.spinee.2004.07.036\">doi:10.1016\/j.spinee.2004.07.036<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/15749614\/\">PubMed 15749614<\/a><\/td><td>Experimental study<\/td><td>lumbar stiffness increases after just one hour of sitting in men (variable in women).<\/td><\/tr>\n<tr><td>S\u00e1nchez-Zuriaga D., Adams M. A., Dolan P. (2010). Is activation of the back muscles impaired by creep or muscle fatigue? <i>Spine<\/i>, 35(5), 517-525. \u2014 <a href=\"https:\/\/doi.org\/10.1097\/BRS.0b013e3181b967ea\">doi:10.1097\/BRS.0b013e3181b967ea<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/20147877\/\">PubMed 20147877<\/a><\/td><td>Experimental study<\/td><td>it is creep, not fatigue, that impairs the muscular protection of the spine.<\/td><\/tr>\n<tr><td>Korakakis V., Giakas G., Sideris V., Whiteley R. (2017). Repeated end range spinal movement while seated abolishes the proprioceptive deficit induced by prolonged flexed sitting posture. <i>Musculoskeletal Science and Practice<\/i>, 31, 9-20. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/j.msksp.2017.06.003\">doi:10.1016\/j.msksp.2017.06.003<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/28624723\/\">PubMed 28624723<\/a><\/td><td>Experimental study<\/td><td>moving the spine corrects the proprioceptive deficit caused by a prolonged flexed posture.<\/td><\/tr>\n<tr><td>Channak S., Spekl\u00e9 E. M., van der Beek A. J., Janwantanakul P. (2024). The effectiveness of a dynamic seat cushion in preventing neck and low-back pain among high-risk office workers: a 6-month cluster-randomized controlled trial. <i>Scandinavian Journal of Work, Environment &amp; Health<\/i>, 50(7), 555-566. \u2014 <a href=\"https:\/\/doi.org\/10.5271\/sjweh.4184\">doi:10.5271\/sjweh.4184<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/39169894\/\">PubMed 39169894<\/a><\/td><td>Randomized controlled trial (6 months)<\/td><td>6-month randomized trial: a dynamic seat cushion reduces the onset of neck and low back pain, with no demonstrated effect on established pain.<\/td><\/tr>\n<tr><td>Channak S. et al. (2024). Effectiveness of a dynamic seat cushion on recovery and recurrence of neck and low back pain in office workers. <i>BMC Musculoskeletal Disorders<\/i>, 25, 850. \u2014 <a href=\"https:\/\/doi.org\/10.1186\/s12891-024-07947-4\">doi:10.1186\/s12891-024-07947-4<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/39448950\/\">PubMed 39448950<\/a><\/td><td>Secondary analysis of the trial<\/td><td>in participants who had pain, faster recovery (1 month versus 3).<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-sbnfa\"><em>Belongs to the SBNFA\u2122 framework:<\/em> The symmetry of the pelvic reserve around the balance point is a principle of the SBNFA\u2122 framework.<\/p>\n<h5 id=\"sources-b3\">B3. Protection against shear and pulling<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Bennett L., Kavner D., Lee B. K., Trainor F. A. (1979). Shear vs pressure as causative factors in skin blood flow occlusion. <i>Archives of Physical Medicine and Rehabilitation<\/i>, 60(7), 309-314. \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/454129\/\">PubMed 454129<\/a><\/td><td>Experimental study (4 subjects)<\/td><td>high shear roughly halves the pressure that cuts off skin blood flow (4 subjects, measured on the hand).<\/td><\/tr>\n<tr><td>Goossens R. H. M. et al. (1994). Influence of shear on skin oxygen tension. <i>Clinical Physiology<\/i>, 14(1), 111-118. \u2014 <a href=\"https:\/\/doi.org\/10.1111\/j.1475-097x.1994.tb00495.x\">doi:10.1111\/j.1475-097x.1994.tb00495.x<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/8149705\/\">PubMed 8149705<\/a><\/td><td>Experimental study<\/td><td>at the sacrum, shear lowers the skin&#8217;s ischemia threshold by about a quarter.<\/td><\/tr>\n<tr><td>Kemmoku T., Furumachi K., Shimamura T. (2013). Force on the sacrococcygeal and ischial areas during posterior pelvic tilt in seated posture. <i>Prosthetics and Orthotics International<\/i>, 37(4), 282-288. \u2014 <a href=\"https:\/\/doi.org\/10.1177\/0309364612465429\">doi:10.1177\/0309364612465429<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/23169902\/\">PubMed 23169902<\/a><\/td><td>Experimental study (30 subjects)<\/td><td>in retroversion, the horizontal force (shear) on the sacrococcygeal region increases in 93% of subjects.<\/td><\/tr>\n<tr><td>Wilke J., Schleip R., Yucesoy C. A., Banzer W. (2018). Not merely a protective packing organ? A review of fascia and its force transmission capacity. <i>Journal of Applied Physiology<\/i>, 124(1), 234-244. \u2014 <a href=\"https:\/\/doi.org\/10.1152\/japplphysiol.00565.2017\">doi:10.1152\/japplphysiol.00565.2017<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/29122963\/\">PubMed 29122963<\/a><\/td><td>Review<\/td><td>the fasciae transmit forces over a distance (cadaver and animal studies).<\/td><\/tr>\n<tr><td>Reichel S. M. (1958). Shearing force as a factor in decubitus ulcers in paraplegics. <i>JAMA<\/i>, 166(7), 762-763. \u2014 <a href=\"https:\/\/doi.org\/10.1001\/jama.1958.62990070004010a\">doi:10.1001\/jama.1958.62990070004010a<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/13502060\/\">PubMed 13502060<\/a><\/td><td>Historical clinical study<\/td><td>shear is a factor in pressure ulcers.<\/td><\/tr>\n<tr><td>Carayannopoulos N. L. et al. (2026). Disorders of the coccyx and sacrococcygeal joint: etiology, diagnosis, and management strategies. <i>The American Journal of Medicine<\/i>, 139(4), 405-412. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/j.amjmed.2025.10.038\">doi:10.1016\/j.amjmed.2025.10.038<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/41241121\/\">PubMed 41241121<\/a><\/td><td>Clinical review<\/td><td>repeated shear of the tailbone sustains inflammation and pain.<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-sbnfa\"><em>Belongs to the SBNFA\u2122 framework:<\/em> The transmission of pulling to the tailbone and the pudendal nerve region (\u201caction at a distance\u201d) is a model of the SBNFA\u2122 framework; it has not been measured in the seated position.<\/p>\n<h5 id=\"sources-c1\">C1. Balance regulation possibilities<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Dubousset J. (2012). L&#8217;homme debout : le rachis et son plan horizontal, scolioses. <i>e-m\u00e9moires de l&#8217;Acad\u00e9mie nationale de chirurgie<\/i>, 11(3), 066-070.<\/td><td>Reference text<\/td><td>the cone of balance: small, constant movements around the line of gravity; role of the hips and ankles.<\/td><\/tr>\n<tr><td>Hasegawa K., Dubousset J. (2022). Cone of Economy with the Chain of Balance \u2014 Historical Perspective and Proof of Concept. <i>Spine Surgery and Related Research<\/i>, 6(4), 337-349. \u2014 <a href=\"https:\/\/doi.org\/10.22603\/ssrr.2022-0038\">doi:10.22603\/ssrr.2022-0038<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/36051675\/\">PubMed 36051675<\/a><\/td><td>Review and proof of concept<\/td><td>within the cone, balance is held with minimal muscle activity.<\/td><\/tr>\n<tr><td>Haddas R., Lieberman I. H. (2018). A method to quantify the \u201ccone of economy\u201d. <i>European Spine Journal<\/i>, 27(5), 1178-1187. \u2014 <a href=\"https:\/\/doi.org\/10.1007\/s00586-017-5321-2\">doi:10.1007\/s00586-017-5321-2<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/29018964\/\">PubMed 29018964<\/a><\/td><td>Experimental study<\/td><td>the cone of economy is quantifiable; a wider cone costs more muscle activity.<\/td><\/tr>\n<tr><td>Gatev P. et al. (1999). Feedforward ankle strategy of balance during quiet stance in adults. <i>Journal of Physiology<\/i>, 514(3), 915-928. \u2014 <a href=\"https:\/\/doi.org\/10.1111\/j.1469-7793.1999.915ad.x\">doi:10.1111\/j.1469-7793.1999.915ad.x<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/9882761\/\">PubMed 9882761<\/a><\/td><td>Experimental study<\/td><td>ankles and hips share the regulation of balance.<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-sbnfa\"><em>Belongs to the SBNFA\u2122 framework:<\/em> Transposing the cone of balance to the seated position is the thesis of the SBNFA\u2122 framework.<\/p>\n<h5 id=\"sources-c2\">C2. Adjustments of the musculoskeletal system<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Dubousset J. (2012). L&#8217;homme debout : le rachis et son plan horizontal, scolioses. <i>e-m\u00e9moires de l&#8217;Acad\u00e9mie nationale de chirurgie<\/i>, 11(3), 066-070.<\/td><td>Reference text<\/td><td>most adjustments of the musculoskeletal system take place in the horizontal plane; the pelvis acts as a \u201cpelvic vertebra.\u201d<\/td><\/tr>\n<tr><td>Yang Y. T., Yoshida Y., Hortob\u00e1gyi T., Suzuki S. (2013). Interaction between thorax, lumbar, and pelvis movements in the transverse plane during gait at three velocities. <i>Journal of Applied Biomechanics<\/i>, 29(3), 261-269. \u2014 <a href=\"https:\/\/doi.org\/10.1123\/jab.29.3.261\">doi:10.1123\/jab.29.3.261<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/22927548\/\">PubMed 22927548<\/a><\/td><td>Experimental study<\/td><td>the pelvis drives trunk rotation in the horizontal plane during walking.<\/td><\/tr>\n<tr><td>van Geffen P., Reenalda J., Veltink P. H., Koopman H. F. J. M. (2009). Decoupled pelvis rotation in sitting: a passive motion technique that regulates buttock load associated with pressure ulcer development. <i>Journal of Biomechanics<\/i>, 42(9), 1288-1294. \u2014 <a href=\"https:\/\/doi.org\/10.1016\/j.jbiomech.2009.03.010\">doi:10.1016\/j.jbiomech.2009.03.010<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/19389679\/\">PubMed 19389679<\/a><\/td><td>Experimental study<\/td><td>rotation of the pelvis when sitting is feasible and regulates the load.<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-sbnfa\"><em>Belongs to the SBNFA\u2122 framework:<\/em> Aporia\u00ae&#8217;s ranges (10\u00b0 of rotation, 1 to 2 cm of translation) are Blue Portance design specifications.<\/p>\n<h5 id=\"sources-c3\">C3. Management of lumbopelvic compensations<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Vleeming A., Schuenke M. D., Masi A. T. et al. (2012). The sacroiliac joint: an overview of its anatomy, function and potential clinical implications. <i>Journal of Anatomy<\/i>, 221(6), 537-567. \u2014 <a href=\"https:\/\/doi.org\/10.1111\/j.1469-7580.2012.01564.x\">doi:10.1111\/j.1469-7580.2012.01564.x<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/22994881\/\">PubMed 22994881<\/a><\/td><td>Review<\/td><td>the sacroiliac joints transfer loads between the spine and the legs.<\/td><\/tr>\n<tr><td>Vleeming A., Stoeckart R., Volkers A. C., Snijders C. J. (1990). Relation between form and function in the sacroiliac joint. Parts I and II. <i>Spine<\/i>, 15(2), 130-132 and 133-136 (PubMed 2326707 for part II). \u2014 <a href=\"https:\/\/doi.org\/10.1097\/00007632-199002000-00016\">doi:10.1097\/00007632-199002000-00016<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/2326706\/\">PubMed 2326706<\/a><\/td><td>Anatomical and functional study<\/td><td>relationship between form and function of the sacroiliac joints (form closure and force closure).<\/td><\/tr>\n<tr><td>Sturesson B., Selvik G., Ud\u00e9n A. (1989). Movements of the sacroiliac joints: a roentgen stereophotogrammetric analysis. <i>Spine<\/i>, 14(2), 162-165. \u2014 <a href=\"https:\/\/doi.org\/10.1097\/00007632-198902000-00004\">doi:10.1097\/00007632-198902000-00004<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/2922636\/\">PubMed 2922636<\/a><\/td><td>Stereophotogrammetric study (25 patients)<\/td><td>the sacroiliac joints really do move, over small ranges (mean rotation 2.5\u00b0, translation 0.7 mm).<\/td><\/tr>\n<tr><td>Willard F. H., Vleeming A., Schuenke M. D., Danneels L., Schleip R. (2012). The thoracolumbar fascia: anatomy, function and clinical considerations. <i>Journal of Anatomy<\/i>, 221(6), 507-536. \u2014 <a href=\"https:\/\/doi.org\/10.1111\/j.1469-7580.2012.01511.x\">doi:10.1111\/j.1469-7580.2012.01511.x<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/22630613\/\">PubMed 22630613<\/a><\/td><td>Review<\/td><td>the thoracolumbar fascia connects the trunk, pelvis, and limbs.<\/td><\/tr>\n<\/tbody><\/table>\n<h5 id=\"sources-c4\">C4. Morphological adaptation to the natural balance profile<\/h5>\n<table class=\"bp-sources-table\"><thead><tr><th scope=\"col\">Source<\/th><th scope=\"col\">Type<\/th><th scope=\"col\">What it establishes for this attribute<\/th><\/tr><\/thead><tbody>\n<tr><td>Legaye J., Duval-Beaup\u00e8re G., Hecquet J., Marty C. (1998). Pelvic incidence: a fundamental pelvic parameter for three-dimensional regulation of spinal sagittal curves. <i>European Spine Journal<\/i>, 7(2), 99-103. \u2014 <a href=\"https:\/\/doi.org\/10.1007\/s005860050038\">doi:10.1007\/s005860050038<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/9629932\/\">PubMed 9629932<\/a><\/td><td>Reference study<\/td><td>pelvic incidence, specific to each person, determines lordosis and sagittal balance.<\/td><\/tr>\n<tr><td>Lazennec J.-Y., Brusson A., Rousseau M.-A. (2011). Hip\u2013spine relations and sagittal balance clinical consequences. <i>European Spine Journal<\/i>, 20(Suppl 5), 686-698. \u2014 <a href=\"https:\/\/doi.org\/10.1007\/s00586-011-1937-9\">doi:10.1007\/s00586-011-1937-9<\/a> \u00b7 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/21796392\/\">PubMed 21796392<\/a><\/td><td>Review<\/td><td>incidence is fixed; hip-spine relationships.<\/td><\/tr>\n<\/tbody><\/table>\n<p class=\"bp-voir\">See also: Hasegawa K., Dubousset J. (2022), presented above.<\/p>\n<p class=\"bp-sbnfa\"><em>Belongs to the SBNFA\u2122 framework:<\/em> The correspondence between wedge and profile is a rule of the SBNFA\u2122 framework and an Aporia\u00ae specification.<\/p>\n<h4 id=\"bibliotheque\">Library of feedback and sources for the comparison<\/h4>\n<p>All the sources cited in the \u201cFeedback and sources\u201d sections of the table, grouped by type.<\/p>\n<h5>Study<\/h5><ul class=\"bp-biblio\"><li>User satisfaction study, pelvic pain unit of CHU de Nantes, Dr. Am\u00e9lie Seneau L\u00e9vesque, report of December 13, 2023 \u2014 <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/sitting-related-pain\/pelvi-seat-study-chu-nantes\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/blueportance.com\/centre-de-connaissances\/dossiers-experts\/assise-douloureuse\/etude-chu-nantes-douleurs-perineales-assise\/<\/a><\/li><li>Live Hearth Well, reporting the Foye 2009 abstract \u2014 <a href=\"https:\/\/livehearthwell.com\/en\/guides\/coccyx-cushion-guide\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/livehearthwell.com\/en\/guides\/coccyx-cushion-guide\/<\/a><\/li><li>Systematic review 2025, \u201cNormative sagittal spinopelvic profiles: a systematic review of the Roussouly classification across different ethnic groups in asymptomatic adults\u201d (PubMed 42104183) \u2014 <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/42104183\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/pubmed.ncbi.nlm.nih.gov\/42104183\/<\/a><\/li><li>Korean study 2017, \u201cEvaluation of Global Sagittal Balance in Korean Adults,\u201d J Korean Neurosurg Soc 2017;60(5):560-566 \u2014 <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC5594629\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC5594629\/<\/a><\/li><\/ul>\n<h5>Named health professional<\/h5><ul class=\"bp-biblio\"><li>Pierre Ivaldi, physiotherapist and osteopath, former managing director (30 years) of the Saint-Jean group&#8217;s post-acute care and functional rehabilitation center, originator of several foundations of the SBNFA\u2122 framework \u2014 video testimonial<\/li><li>Dr. Anne Lassaux, pain physician, no declared conflict of interest \u2014 <a href=\"https:\/\/blueportance.com\/en\/shared-experiences\/aporia-reviews-dynamic-seating\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/blueportance.com\/partager-nos-experiences\/avis-utilisateurs\/<\/a><\/li><li>S\u00e9bastien Bottau, physiotherapist, Spine Unit \/ Back School, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer) \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/<\/a><\/li><\/ul><h5>Article by a clinician or ergonomist<\/h5><ul class=\"bp-biblio\"><li>Ageproof, 3-week test of an 8\u00b0 wedge \u2014 <a href=\"https:\/\/www.ageproof.co.uk\/reviews\/devices\/sitting-wedge-review\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.ageproof.co.uk\/reviews\/devices\/sitting-wedge-review\/<\/a><\/li><li>Biology Insights, How to Sit on a Donut Pillow \u2014 <a href=\"https:\/\/biologyinsights.com\/how-to-sit-on-a-donut-pillow-for-maximum-relief\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/biologyinsights.com\/how-to-sit-on-a-donut-pillow-for-maximum-relief\/<\/a><\/li><li>Clinique OPS (sloped versions) \u2014 <a href=\"https:\/\/www.cliniqueops.com\/pathologies-posturales\/coussin-postural-sur-mesure-blog-article-217-fr.htm\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.cliniqueops.com\/pathologies-posturales\/coussin-postural-sur-mesure-blog-article-217-fr.htm<\/a><\/li><li>Dr. R. Naples (urologist), How to Sit With Pudendal Neuralgia \u2014 <a href=\"https:\/\/www.drrnaples.com\/how-to-sit-with-pudendal-neuralgia\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.drrnaples.com\/how-to-sit-with-pudendal-neuralgia<\/a><\/li><li>Flexi Chair, Best Coccyx Cushions 2026 \u2014 <a href=\"https:\/\/flexi-chair.com\/accessories\/best-coccyx-cushions-tailbone-pain-2026\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/flexi-chair.com\/accessories\/best-coccyx-cushions-tailbone-pain-2026\/<\/a><\/li><li>Grabberstool, Donut vs Wedge \u2014 <a href=\"https:\/\/grabberstool.com\/blogs\/news\/donut-cushion-vs-wedge-cushion-tailbone\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/grabberstool.com\/blogs\/news\/donut-cushion-vs-wedge-cushion-tailbone<\/a><\/li><li>Orthoptimal, shapes and selection criteria \u2014 <a href=\"https:\/\/orthoptimal.fr\/blogs\/ortho-conseils-le-blog\/coussin-orthopedique-fessier-lequel-choisir-en-cas-de-douleur-au-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/orthoptimal.fr\/blogs\/ortho-conseils-le-blog\/coussin-orthopedique-fessier-lequel-choisir-en-cas-de-douleur-au-coccyx<\/a><\/li><li>Your Body Posture \u2014 <a href=\"https:\/\/yourbodyposture.com\/best-seat-wedges-anterior-pelvic-tilt\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/yourbodyposture.com\/best-seat-wedges-anterior-pelvic-tilt\/<\/a><\/li><\/ul>\n<h5>User testimonial<\/h5><ul class=\"bp-biblio\"><li>Physiotherapy trainee in lumbar rehabilitation, Back School, P\u00f4le Sant\u00e9 Saint Jean (Cagnes-sur-Mer) \u2014 <a href=\"https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.polesantesaintjean.fr\/kinesitherapie\/<\/a><\/li><li>Customer reviews, The White Willow \u2014 <a href=\"https:\/\/thewhitewillow.in\/products\/sky-hr-foam-donut-shaped-seat-cushion-tailbone-and-lumber-support-firm\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/thewhitewillow.in\/products\/sky-hr-foam-donut-shaped-seat-cushion-tailbone-and-lumber-support-firm<\/a><\/li><li>User reviews reported by Corner Office HQ \u2014 <a href=\"https:\/\/cornerofficehq.com\/best-coccyx-seat-cushions\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/cornerofficehq.com\/best-coccyx-seat-cushions\/<\/a><\/li><li>User, pudendal neuralgia forum (Reddit) \u2014 <a href=\"https:\/\/www.reddit.com\/r\/PudendalNeuralgia\/comments\/1f8dxol\/office_chair_recommendation\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.reddit.com\/r\/PudendalNeuralgia\/comments\/1f8dxol\/office_chair_recommendation\/<\/a><\/li><\/ul>\n<h5>Independent review platform<\/h5><ul class=\"bp-biblio\"><li>Trustpilot, Blue Portance reviews (4.7\/5) \u2014 <a href=\"https:\/\/fr.trustpilot.com\/review\/blueportance.com\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/fr.trustpilot.com\/review\/blueportance.com<\/a><\/li><\/ul><h5>Reviews and testimonials hosted by the seller<\/h5><ul class=\"bp-biblio\"><li>B\u00e9atrice D., customer testimonial \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/blueportance.com\/produits\/coussin-nevralgie-pudendale-aporia\/<\/a><\/li><li>Daniele W., verified customer review, Alcock Rest (4\u2605) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html<\/a><\/li><li>J\u00e9r\u00e9my H., verified customer review, Alcock Rest (5\u2605) \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html<\/a><\/li><\/ul><h5>Manufacturer or seller<\/h5><ul class=\"bp-biblio\"><li>Askned, Pudendal Channel Cushion \u2014 <a href=\"https:\/\/askned.com.au\/seating-sleeping-and-body-support\/body-support-and-comfort\/back-and-body-supports\/pudendal-channel-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/askned.com.au\/seating-sleeping-and-body-support\/body-support-and-comfort\/back-and-body-supports\/pudendal-channel-cushion\/<\/a><\/li><li>Aylio, Donut vs twin cutouts \u2014 <a href=\"https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/aylio.com\/donut-cushion-vs-cutout-seat-cushion\/<\/a><\/li><li>Cusheal, Buyer&#8217;s Guide \u2014 <a href=\"https:\/\/cusheal.com\/blogs\/blog\/best-tailbone-cushion-buyers-guide\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/cusheal.com\/blogs\/blog\/best-tailbone-cushion-buyers-guide<\/a><\/li><li>Ergotech, comparison of Alcock Rest versions \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/smartblog\/307_comparison-pudendal-cushion.html\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.ergotech.fr\/en\/smartblog\/307_comparison-pudendal-cushion.html<\/a><\/li><li>Ergotech, Alcock Rest product sheet \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.ergotech.fr\/en\/pudendal-nerve-cushion\/29-alcock-rest.html<\/a><\/li><li>Ergotech, limitations of the wedge \u2014 <a href=\"https:\/\/www.ergotech.fr\/en\/smartblog\/290_top-3-car-seat-cushions.html\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.ergotech.fr\/en\/smartblog\/290_top-3-car-seat-cushions.html<\/a><\/li><li>Orthexa, coccyx cushion \u2014 <a href=\"https:\/\/orthexa.fr\/coussin-coccyx-pour-soulager-la-douleur-assise\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/orthexa.fr\/coussin-coccyx-pour-soulager-la-douleur-assise\/<\/a><\/li><li>Orvimed, SYSTAM donut cushion product sheet \u2014 <a href=\"https:\/\/www.orvimed.fr\/maintien-a-domicile\/54-coussin-de-positionnement-bouee.html\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.orvimed.fr\/maintien-a-domicile\/54-coussin-de-positionnement-bouee.html<\/a><\/li><li>Pelican Manufacturing, Pudendal Channel Cushion \u2014 <a href=\"https:\/\/pelicanmanufacturing.com\/product\/pudendal-channel-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/pelicanmanufacturing.com\/product\/pudendal-channel-cushion\/<\/a><\/li><li>Sameo, product sheet \u2014 <a href=\"https:\/\/www.sameo.fr\/products\/coussin-orthopedique-coccyx-sameo\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/www.sameo.fr\/products\/coussin-orthopedique-coccyx-sameo<\/a><\/li><li>Sihoo, expert guide \u2014 <a href=\"https:\/\/fr.sihoo.com\/blogs\/guide-dachat\/chaise-bureau-douleur-coccyx\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/fr.sihoo.com\/blogs\/guide-dachat\/chaise-bureau-douleur-coccyx<\/a><\/li><li>Sit Cushion \u2014 <a href=\"https:\/\/sitcushion.com\/u-shape-coccyx-cushion-or-donut\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/sitcushion.com\/u-shape-coccyx-cushion-or-donut\/<\/a><\/li><li>Sit Cushion \u2014 <a href=\"https:\/\/sitcushion.com\/donut-pillows-vs-coccyx-cutouts-which-pressure-relief-cushion-is-right-for-you\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/sitcushion.com\/donut-pillows-vs-coccyx-cutouts-which-pressure-relief-cushion-is-right-for-you\/<\/a><\/li><\/ul>\n<h5>Blue Portance<\/h5><ul class=\"bp-biblio\"><li>Blue Portance, APORIA\u00ae design specifications \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/blueportance.com\/produits\/coussin-nevralgie-pudendale-aporia\/<\/a><\/li><li>Blue Portance, manufacturer&#8217;s position \u2014 <a href=\"https:\/\/blueportance.com\/en\/products\/aporia-perinee-pudendal-neuralgia-cushion\/\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/blueportance.com\/produits\/coussin-nevralgie-pudendale-aporia\/<\/a><\/li><li>SBNFA\u2122 doctrine<\/li><li>APORIA\u00ae doctrinal position<\/li><\/ul>\n<h4>APORIA\u00ae-specific data<\/h4>\n<p>CHU de Nantes user satisfaction study: see the <a href=\"https:\/\/blueportance.com\/en\/knowledge-base\/expert-guides\/sitting-related-pain\/pelvi-seat-study-chu-nantes\/\">study file<\/a>. Blue Portance support corpus: qualitative observations. The APORIA\u00ae ranges and configurations cited in the sheets are design specifications.<\/p>\n<p class=\"bp-attribution\">Framework developed by Blue Portance under the scientific direction of Gil Ayache, PhD \u2014 Mines Paris \u2013 PSL, with the assistance of ChatGPT, Perplexity, Vibe, Gemini, and Claude for analysis, literature research, writing, and consolidation. Scientific and methodological decisions rest with Blue Portance. Version 23 of November 12, 2026. English translation of the original French version.<\/p>\n<\/section>\n<\/article>\n","protected":false},"excerpt":{"rendered":"<p>Seat cushion comparison: what do they allow the body to do? Blue Portance guide \u00b7 SBNFA\u2122 framework \u00b7 version 23 of November 12, 2026 Part A What this guide is about This comparison does not only look at what a cushion is made of: it examines what it allows the body to do. Quick decision [&#8230;]\n","protected":false},"author":6,"featured_media":0,"parent":7981,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_yoast_wpseo_title":"Coccyx cushion, donut or perineal cushion? Comparison | Blue Portance","_yoast_wpseo_metadesc":"Coccyx cushion, donut, pudendal neuralgia cushion or APORIA\u00ae: 11 attributes compared, with sources and real-world evidence.","footnotes":""},"pathologie_secondaire":[],"effet_positif":[],"class_list":["post-11057","page","type-page","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v28.8 (Yoast SEO v28.8) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Coccyx cushion, donut or perineal cushion? 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