Multidirectional measures of seated postural stability

Objective. To quantify the limits of stability during a leaning/reaching task and determine (1) test–retest reliability and (2) effect of movement direction and foot support. Design. Test–retest reliability design. Background. Seated reaching and leaning are used in rehabilitation programs to assess and train sitting balance and motor function. Continuous (as opposed to ordinal), multidirectional measures of seated postural stability have not been previously presented. Methods. Twelve older adults performed a seated reaching/leaning task while net body centre of pressure displacement and velocity were measured with three forceplates (under buttocks and each foot) over two separate days. Conditions of movement direction (forward, backward, lateral) and foot support (with and without) were randomized. Results. Except for the backward movement in the supported foot condition, all measures had moderate to very high reliability. Measurements were sensitive to both foot support and movement direction.