Isokinetic performance and knee muscle balance in young basketball players: Reference values for physical preparation programs

Introduction Isokinetic assessment is considered the gold standard for evaluating knee muscle performance and balance and provides objective information about muscle function. Objective To evaluate the isokinetic knee muscle profile of male adolescent basketball players aged 10–18 years. Methods This cross-sectional study used an evaluation form to collect participants' demographic characteristics, personal history, and sports-related information. Knee muscle performance was assessed using a Biodex System 4 isokinetic dynamometer at a fixed angular velocity of 60°/s in continuous mode. Data were analyzed using R statistical software (version 4.2.1). Paired t-tests were used to compare concentric and eccentric torque values and reciprocal muscle ratios between the dominant and non-dominant limbs. Mean differences, 95% confidence intervals, and Cohen's d ᶻ effect sizes were calculated. Statistical significance was set at p < 0.05. Results Fifty-seven male basketball players (15.0 ± 2.13 years) were included. No significant differences were found in concentric or eccentric knee extensor or flexor torque between limbs. Functional and eccentric reciprocal ratios were also similar. The concentric reciprocal ratio was significantly higher in the dominant limb (p = 0.008), although the effect size was small. Individual bilateral asymmetries >10% were frequently observed. Conclusion Young male basketball players demonstrated high bilateral symmetry in isokinetic knee torque and most reciprocal muscle ratios. Despite a small difference in the concentric reciprocal ratio, these findings provide reference values for the isokinetic assessment of adolescent basketball players. The cross-sectional design precludes conclusions regarding training effects or injury prevention.