LAUSR

CONTEXT Patients with chronic ankle instability (CAI) frequently display altered movement patterns during functional movements. However, conflicting results regarding movement patterns during jump-landing movements often hinder clinicians in developing proper rehabilitation programs for the CAI population. Calculating joint energetics offers a novel method to overcome discrepancies in movement patterns by individuals with and without CAI. OBJECTIVE To determine differences in energy dissipation and generation by the lower extremity during maximal jump-landing/cutting among groups with CAI, copers, and controls. DESIGN Cross-sectional Study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Forty-four patients with CAI (25 men, 19 women; age=23.1 ± 2.2 years, height=1.75 ± 0.1 m; mass=72.6 ± 11.2 kg), 44 copers (25 men, 19 women; age=22.6 ± 2.3 years, height=1.74 ± 0.1 m; mass=71.2 ± 12.9 kg), and 44 controls (25 men, 19 women; age=22.6 ± 2.5 years, height=1.74 ± 0.1 m; mass=69.9 ± 10.6 kg). MAIN OUTCOME MEASURES(S) Biomechanics of the lower extremity and ground reaction force data were collected during a maximal jump-landing/cutting task. The product of angular velocity and joint moment data represented joint power. Energy dissipation and generation by the ankle, knee, and hip joints were calculated by integrating regions of the joint power curve. RESULTS Patients with CAI displayed reduced ankle energy dissipation and generation (P < .01) compared to copers and controls during maximal jump-landing/cutting. Patients with CAI also displayed more dissipation of knee energy than copers during the loading phase and more generation of hip energy than controls during the cutting phase. However, copers displayed no differences in joint energetics compared with controls. CONCLUSIONS Patients with CAI changed both energy dissipation and generation by the lower extremity during maximal jump-landing/cutting. However, copers did not change their joint energetics, which may represent a coping mechanism to avoid further injuries.