Lower Extremity Energy Dissipation and Generation During Jump Landing and Cutting in Patients With Chronic Ankle Instability.

CONTEXT: Participants with chronic ankle instability (CAI) frequently display altered movement patterns during functional movements. However, it remains unclear how these altered joint kinematics during jump landing negatively affect ankle joint health in the CAI population. Calculating joint energetics may offer an important method to estimate the magnitude of lower extremity joint loading during functional movements in participants with CAI.

OBJECTIVE

To determine differences in energy dissipation and generation by the lower extremity during maximal jump landing and cutting among groups with CAI, copers, and controls.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PATIENTS OR OTHER

PARTICIPANTS

Forty-four participants with CAI, 44 copers, and 44 controls.

MAIN OUTCOME MEASURES(S): Kinematics and kinetics of the lower extremity and ground reaction force data were collected during a maximal jump-landing and cutting task. The product of angular velocity in the sagittal plane 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

Participants with CAI displayed reduced ankle energy dissipation (35.9% ± 10.1%) and generation (31.6% ± 12.8%; P < .01) compared with copers (dissipation = 43.6% ± 11.1%; generation = 40.4% ± 12.0%) and controls (dissipation = 41.3% ± 11.1%; generation = 39.6% ± 12.0%) during maximal jump landing and cutting. Participants with CAI also displayed greater energy dissipation at the knee (45.1% ± 9.1%) than copers (39.7% ± 9.5%) during the loading phase and greater energy generation at the hip than controls (36.6% ± 16.8% versus 28.3% ± 12.8%) during the cutting phase. However, copers displayed no differences in joint energetics compared with controls.

CONCLUSIONS

Participants with CAI displayed differences in both energy dissipation and generation by the lower extremity during maximal jump landing and cutting. However, copers did not show altered joint energetics, which may represent a coping mechanism to avoid further injuries.