Is There a Correlation Between Knee Extension Peak Torque Quadriceps Maximal Force and Biomechanical Determinants in Hop Tests of the MERItest, 6 months After ACL Reconstruction?

OBJECTIVE

To investigate the relationship between isokinetic knee extension peak torque and specific biomechanical variables during hop tests in patients 6 months postanterior cruciate ligament reconstruction (ACLR).

DESIGN

Prospective, cross-sectional study analyzing the correlations between isokinetic knee extension torque and biomechanical outcomes across various functional tests.

SETTING

Sports clinic with a specialized biomechanics laboratory.

PARTICIPANTS

Sixty-one patients (47 males, 14 females), aged 16 to 55 years, who had undergone ACLR, participated. All met the inclusion criteria and completed the follow-up testing at 6 months postsurgery.

ASSESSMENT OF RISK FACTORS: Key independent variables included isokinetic knee extension peak torque. Participants completed standardized functional tests: single-leg and double-leg drop jumps, single-leg hop tests, and double-leg countermovement jumps.

MAIN OUTCOME MEASURES: Outcome measures included biomechanical parameters related to dynamic knee stability, including peak knee extensor moments, knee joint power during push-off, peak knee flexion and valgus, and vertical ground reaction force and braking forces.

RESULTS

Moderate correlations were observed between knee extension peak torque and select biomechanical variables, including peak knee extensor moments during single-leg drop jumps, knee joint power during push-off phases in both single and double-leg drop jumps, and peak braking forces in single-leg hop tests. However, these relationships suggest that additional factors play essential roles in dynamic stability.

CONCLUSIONS

Although quadriceps strength is moderately linked to key biomechanical markers, our findings indicate that a more comprehensive assessment, integrating both strength and biomechanical evaluation, could enhance ACLR rehabilitation strategies. This combined approach may better support recovery and minimize reinjury risk.