Preseason isokinetic profile of knee flexors and extensors in 30 French elite professional basketball players

Abstract

Basketball is an aerobic-based anaerobic contact pivot sport with a high knee injury rate. Isokinetic assessment of knee extensor and flexor muscle is currently used in elite athletes for preseason evaluation with the aim of detecting muscular imbalance and preventing orthopedic or muscular injuries. However, only few studies have described isokinetic performances in elite basketball players. The aim of this study is to describe preseason isokinetic knee extensor and flexor muscle strength profile in professional basketball players. Thirty professional basketball players underwent a preseason isokinetic examination to evaluate the knee extensor and flexor concentric peak torque at 60°.s-1 and 240°.s-1 and flexor eccentric peak torque at 30°. s-1, using a ConTrex ® dynamometer. Statistical analysis was performed with a paired Wilcoxon Signed-Rank Test. No systematic significant difference was found between dominant or non-dominant side for: knee extensor and flexor muscle strength and knee flexor/extensor strength conventional or mixed ratios. Average deficit for agonist muscle between dominant and non-dominant side was < 10% for all muscle and contraction velocity tested. Average conventional flexor/extensor ratio ranged from 60 ± 12% to 67 ± 18%. Average mixed flexor/extensor ratio was of 99 ± 19% and 104 ± 25%, respectively for dominant and non-dominant lower limb. According to the criteria used by Croisier et al. (2008) to define muscle strength imbalance, 13 of 30 players (43%) had a preseason isokinetic muscle strength imbalance, with a potential indication for a specific compensating training. Isokinetic professional basketball players profile is unclear and the presence of a muscular strength asymmetry linked to the intensive basketball practice remains controversial. Although we observed a light trend in favor of the dominant lower limb in term of strength, our study showed no statistically significant difference between the dominant and non-dominant side, but the sample size was limited. A lot of players presented a strength imbalance and had a non-isokinetic compensating training but no isokinetic control. Further studies are needed to check if a compensating training could normalize isokinetic parameters and decrease injury rate in professional basketball players, who have a frequent history of knee injury.