We describe feedforward neuromuscular control during a maximal jump landing/cutting task among groups of chronic ankle instability (CAI), coper, and uninjured control subjects. Sixty-six volunteers participated (22 CAI, 22 copers, and 22 uninjured controls). The subjects completed five trials of a maximal jump landing/cutting manoeuvre. Three-dimensional ground reaction force, lower-extremity joint angles, and activation of eight muscles were collected from 150 ms prelanding to initial contact. Functional analyses of variance (FANOVA) were used to evaluate between-group differences for these outcome variables. Compared to uninjured controls, both CAI patients and copers demonstrated altered sagittal lower-extremity movements. However, only copers exhibited unique kinematic alterations in frontal lower-extremity kinematics in the ankle and hip joints. While CAI patients demonstrated decreased most of lower-extremity EMG activation, copers displayed increased EMG activation during prelanding. Current data suggest that both CAI patients and copers demonstrated alterations in feedforward neuromuscular control prior to initial contact during a demanding jump landing/cutting task. Altered movement strategies during prelanding were observed in both proximal (e.g., knee and hip) and distal (e.g., ankle) joints in CAI patients and copers, while copers presumably had more protective jump landing/cutting movement strategies than CAI patients.
Keywords: Chronic ankle instability; electromyography; feedforward motor control; functional movement pattern; lateral ankle sprain coper.