Ankle trauma significantly impairs posture control--a study in basketball players and controls.

Both ankle and hip movements are used to maintain balance in strategies defined as bottom up and top down models. This suggests that pathological impairment of either of these articulations could modify the parameters of balance control. In order to appreciate the bearing of ankle damage on the proper control of equilibrium, posturographic recordings were compared, in a static and two dynamic tests, between 15 professional national basketball players, with histories of 10 to 15 ankle sprains, and 50 controls. In statokinesigrams obtained with eyes open or closed, center of foot pressure displacements were of similar length (way) between controls and players, while the area covered was increased for the latter and related to the history of ankle trauma. In a toes-up dynamic test (4 degrees, 50 degrees/s) coupled with electromyographic recordings, the short latency response (myotatic reflex in the triceps surae muscle) normalized to one meter body height, was shorter in players without relationship to histories of ankle damage. In a prolonged sinusoidal dynamic test, players with the largest number of ankle trauma showed greater difficulties in maintaining posture control. These data pinpoint the role of ankles in the control of both static and dynamic balance and demonstrate that the role of the hip joints becomes more important (top down strategy) in the case of damaged ankles.