Association between pre-season lower limb interlimb asymmetry and non-contact lower limb injuries in elite male volleyball players

This study aimed to quantify lower limb interlimb asymmetries in elite male volleyball players by assessing key performance measures, including vertical jumps, change of direction, and muscle strength. It further explored the potential association between these asymmetries and the occurrence of non-contact lower limb injuries. Thirty-one elite male volleyball athletes (age: 20.1 ± 1.2 years; training experience: 7.1 ± 2.2 years) participated in the study. Interlimb asymmetries were assessed using the single-leg countermovement jump (SCMJ), squat jump (SSJ), drop jump (SDJ), T-test, and Pro-test to evaluate lower limb power, agility, and change-of-direction ability. Concentric and eccentric strengths of the knee extensors and flexors were measured using isokinetic testing. Athletes were monitored for 8 months to record non-contact lower limb injuries. Significant variability was observed in the lower extremity interlimb asymmetries (ranging from 3.61 to 15.91%) across different tests (P < 0.05). Thirteen athletes sustained at least one non-contact lower limb injury during the follow-up period. Logistic regression analysis identified significant predictors of injury risk: knee extensor concentric normalized peak torque asymmetry (OR 1.64 [95% CI 1.14-2.37]; P < 0.01), SCMJ height asymmetry (OR 1.18 [95% CI 1.01-1.34]; P < 0.05), and T-test performance asymmetry (OR 1.41 [95% CI 1.07-1.85]; P < 0.05). Interlimb asymmetries in SCMJ, knee extensor strength, and T-test performance are significant risk factors for non-contact lower limb injuries in elite male volleyball players. Systematic evaluation of these asymmetries could contribute to targeted injury prevention strategies and optimized athletic performance.