Functional derivation · SBNFA™

Postural compensation

A postural compensation is an adjustment by which a region of the body changes its position or its activity to maintain a function (balance, horizontal gaze, performing a task) in the face of a load, a limitation or an imbalance.

Scientific basis

The concept is a general one in biomechanics and in clinical practice. A well-documented example concerns the sagittal balance of the spine: when the trunk shifts forward, the pelvis tilts posteriorly, the hips extend and the knees may flex to maintain horizontal gaze and standing balance.

"Muscle compensation," in the sense of one muscle substituting for another, is a special case. A compensation is not a pathology: it is a way of maintaining a function.

Blue Portance / SBNFA™ reading

The SBNFA™ framework classifies compensations by their mechanical outcome. A compensation is called positive when it is accompanied by distribution and redistribution of stress, in functional economy. It is called negative when it leads to an accumulation or a concentration of stress, up to a bottleneck, and becomes cumulative. "Positive" and "negative" are not clinical judgments.

In static sitting, the possibilities for redistribution are limited; the mobility of the pelvis, particularly in the horizontal plane, and that of the sacroiliac joints contribute to adjustments and to stress redistribution.

Contribution to the analysis of sitting

Seating analysis observes preferred support areas, lasting asymmetries and how they evolve over time. It does not classify a compensation as positive or negative without describing its mechanism, and it does not make a diagnosis.

Not to be confused with

Postural adaptability, a functional capacity; postural strategies, modes of organization of postural control; muscle compensation, a special case in which one muscle substitutes for another; pathology: a compensation is not one.

Sources and scope

Barrey et al. (2013): compensatory mechanisms of sagittal spinal balance (European Spine Journal)

An established biomechanical and clinical concept in the general sense. The distinction between positive and negative compensations is a reading specific to the SBNFA™ framework; it is neither a diagnosis nor evidence of a clinical benefit.