Which trunk inclination directions best predict multidirectional-seated limits of stability among individuals with spinal cord injury?

OBJECTIVE To determine which trunk inclination directions most accurately predict multidirectional-seated limits of stability among individuals with spinal cord injury (SCI). DESIGN Predictive study using cross-sectional data. SETTING Pathokinesiology Laboratory. PARTICIPANTS Twenty-one individuals with complete or incomplete sensorimotor SCI affecting various vertebral levels participated in this study. INTERVENTIONS Participants were instructed to lean their trunk as far as possible in eight directions, separated by 45° intervals, while seated on an instrumented chair with their feet positioned on force plates. OUTCOMES MEASURES Eight direction-specific stability indices (DSIs) were used to define an overall stability index (OSI) (limits of stability). RESULTS All DSIs significantly correlated with the OSI (r = 0.816-0.925). A protocol that only tests the anterior, left postero-lateral, and right lateral trunk inclinations accurately predicts multidirectional-seated postural stability (r(2) = 0.98; P < 0.001). CONCLUSION Multidirectional-seated postural stability can be predicted almost perfectly by evaluating trunk inclinations performed toward the anterior, left postero-lateral, and right lateral directions.