Muscle force contributions to ankle joint contact forces during an unanticipated cutting task in people with chronic ankle instability

The purpose of this study was to compare muscle force contributions ankle joint compression and anteroposterior shear forces between people with chronic instability (CAI) healthy controls (CON) during an unanticipated cutting task. Eleven CAI 11 CON performed task as three-dimensional motion capture, ground reaction (GRF), activation data were collected. A musculoskeletal modeling used calculate talocrural parse out the these from ankle-spanning muscles GRF. Independent t-tests for statistical analysis. People exhibited greater anterior peaks early (p = 0.048, d 0.98) late 0.017, 1.21) stance compared CON. difference in appeared arise GRF contribution 0.026, 1.12) group, whereas lateral gastrocnemius 1.12), medial 0.98), tibialis posterior 1.22), fibularis brevis 0.035, 1.05), longus 0.023, 1.15). exhibit shear, but not compressive differences result passive active lower leg stance, respectively.