Comparison of Performance Parameters of Professional Football Players with Unilateral Anterior Cruciate Ligament Reconstruction to the Contralateral Extremity

BACKGROUND/AIMS: Anterior cruciate ligament (ACL) injury and reconstruction can lead to persistent neuromuscular deficits and impaired athletic performance. However, the extent of inter-limb asymmetry in professional football players after unilateral ACL reconstruction (ACLR) remains unclear. This study aimed to compare reaction time, knee proprioception, isometric muscle strength, and vertical jump performance between the operated limb and the contralateral healthy limb in professional football players with a history of unilateral ACLR. MATERIALS AND METHODS: In this cross-sectional, paired-design study, 15 professional football players were evaluated. All assessments were performed by a single experienced physiotherapist. Simple reaction time was measured using the Nelson Foot Reaction Test. Knee proprioception was assessed using a validated smartphone inclinometer application. Isometric muscle strength of the quadriceps, hamstrings, gluteus maximus, and gluteus medius was measured bilaterally using a calibrated hand-held dynamometer. Vertical jump performance was evaluated with a VertiMetric device using the squat-jump protocol; mean jump height (cm) and power (W) were recorded. RESULTS: There were no statistically significant differences between the operated and contralateral limbs for any outcome (p>0.05). The operated limb showed small, nonsignificant deficits in reaction time, hamstring and gluteal strength, and vertical jump performance compared with the healthy limb. Quadriceps strength was effectively symmetrical. Proprioceptive differences were inconsistent and non-significant across angles. CONCLUSION: Clinically, ~6 years after unilateral ACLR, professional footballers in our cohort demonstrated largely restored limb symmetry in reaction time, proprioception, isometric strength, and squat-jump performance; small residual hamstring/gluteal and jump deficits-though not statistically significant-support continued targeted strengthening and limb symmetry monitoring during return to sport follow-up.