Limb Strength and Power Asymmetries in Professional Team Sport Athletes at Return-to-Sport Testing Following ACL Reconstruction

Background and Objectives: Present assessment methods have not effectively mitigated the risk of recurrent anterior cruciate ligament (ACL) injury following reconstruction (ACLR), suggesting that critical neuromuscular deficits may be underdiagnosed. This study aimed to compare limb asymmetries across strength, concentric and eccentric power, and deceleration metrics during return-to-sport (RTS) testing in professional athletes post-ACLR. Materials and Methods: Forty-four participants (33 males, 11 females; age 22.5 ± 5.8 years, body mass 75.9 ± 13.0 kg, height 180.5 ± 8.38 cm) (mean ± SD) with a unilateral reconstructed ACL (BTB = 33, HT = 11 graft) were included. They underwent isokinetic testing of knee flexor and extensor strength and bilateral countermovement jump (CMJ) assessments to measure concentric and eccentric peak power and deceleration metrics. Limb symmetry indices (LSI) were calculated for each parameter. Welch’s ANOVA and Games–Howell post hoc tests were used to compare LSIs among parameters. Results: Welch’s ANOVA showed that limb symmetry differed significantly across the measured neuromuscular parameters (F = 12,59, p < 0.001). Knee flexor strength LSI was significantly higher than knee extensor strength LSI (p = 0.003; d = 1.18), concentric peak power LSI (p < 0.001, d = 1.44), eccentric peak power LSI (p = 0.001, d = 1.71), and deceleration LSI (p = 0.001, d = 2.09). In addition, deceleration LSI was significantly lower than knee extensor strength LSI (p = 0.001, d = 1.34) and concentric peak power LSI (p = 0.007, d = 1.10). No significant difference was found between concentric and eccentric peak power, nor between knee extensor strength and either concentric or eccentric peak power LSIs. Conclusions: The findings of this study revealed significantly greater asymmetries in load absorption capacity compared to strength and concentric power measures at return-to-sport time frame in professional athletes post-ACLR.