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

Abstract

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 (R2 = 20.1%) and RSI (R2 = 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.