Residual Deficits in Reactive Strength After Anterior Cruciate Ligament Reconstruction in Soccer Players

Context: Deficits in plyometric abilities are common after anterior cruciate ligament reconstruction (ACLR). Vertical rebound tasks may provide a targeted evaluation of knee function. Objective: To examine the utility of a vertical hop test for assessing function after ACLR and establishing factors associated with performance. Design: Cross-sectional study. Setting: Rehabilitation program. Patients or Other Participants: Soccer players with a history of ACLR (n = 73) and matched control individuals (n = 195). Main Outcome Measure(s): The 10-second vertical hop test provided measures of jump height, the Reactive Strength Index (RSI), and asymmetry. We also examined possible predictors of hop performance, including single-legged vertical drop jump, isokinetic knee-extension strength, and the International Knee Documentation Committee questionnaire score. Results: Between-limbs differences were identified only for the ACLR group, and asymmetry scores increased in those with a history of ACLR (P, .001) compared with the control group. The single-legged vertical drop jump, RSI, and knee-extension torque were significant predictors of 10-second hop height (R ² = 20.1%) and RSI (R ² = 47.1%). Conclusions: Vertical hop deficits were present after ACLR, even after participants completed a comprehensive rehabilitation program. This may have been due to reduced knee-extension and reactive strength. Vertical hop tests warrant inclusion as part of the return-to-sport test battery.