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.