Isokinetic Muscle Strength in Elite Soccer Players 3 and 6 months After Anterior Cruciate Ligament Reconstruction

Milutinovic, A, Jakovljevic, V, Dabovic, M, Faude, O, Radovanovic, D, and Stojanovic, E. Isokinetic muscle strength in elite soccer players 3 months and 6 months after anterior cruciate ligament reconstruction. J Strength Cond Res 37(4): e297-e304, 2023-The aim of this study was to evaluate interlimb symmetry in quadriceps and hamstring peak torque of elite soccer players at 3 months (stage 1) and 6 months (stage 2) after anterior cruciate ligament (ACL) reconstruction. Eight male professional soccer players competing at the highest level across different European countries, who had undergone ACL reconstruction, participated in this study. All patients underwent a supervised physiotherapy program after surgery. Data analyses included the use of separate two-way repeated-measures analyses of variance and effect sizes. Although knee extensor and flexor strength of the non-injured limb was found to be relatively unaltered (g = -0.10 to 0.00) between stage 1 and stage 2, comparisons across time points revealed moderate improvements in quadriceps peak torque (p = 0.01, g = 0.52), hamstring peak torque (p = 0.07, g = 0.51), and hamstring:quadriceps (H/Q) ratio (p = 0.03, g = -0.68) of the injured leg, as well as small-large improvements in the quadriceps (p = 0.004, g = 1.24) and hamstring limb symmetry index (LSI) (p = 0.056, g = 0.41). A time-dependent moderate-large asymmetry observed at stage 1 between the injured and noninjured leg in quadriceps peak torque (p < 0.001, g = -1.83), hamstring peak torque (p = 0.157, g = -0.67), and the H:Q ratio (p = 0.06, g = 1.01), as well as between the hamstring and quadriceps LSI (p = 0.03, g = -0.74) was eliminated at stage 2 (g = -0.31 to 0.42). Our findings indicate the importance of supervised and comprehensive therapy, as well as strength screening to assist in recovery aimed at optimizing identified strength deficits following ACL reconstruction.