Investigation of the effects of lower limb asymmetries on football-specific agility and sprint performance in football players

Objective: This study aimed to assess the level of lower limb asymmetries in youth male soccer players and focused on the effects of these asymmetries on football- specific agility (with and without ball), change of direction (COD) and sprint performance. In addition, it also aimed to investigate the relationship between the level of jump asymmetry (low, medium and high asymmetry) and football players' agility, COD and sprint performance. Method: The lower limb asymmetries in football players, right and left, were measured in the single leg hop test (SLH), single leg side hop test (SLSH), single leg triple hop test (SLTH) and single leg crossover hop test (SLCH). To analyse the effects of asymmetries on performance, sprint test (20 meters), COD test and agility (with and without ball) tests were measured. Results: Football players with high asymmetry levels showed significantly lower jump performance in both legs, especially in the SLCH and SLTH tests (p < .001). SLCH asymmetry was significantly and moderately positively correlated with motor performance tests such as sprinting, agility and change of direction (r = 0.30-0.38), suggesting that performance decreases as asymmetry increases. Conclusion: Hop asymmetry levels may affects sprint, agility and change of direction performance in soccer players. In particular, the jump performances of football players with high asymmetry levels in SLCH and SLTH jump tests were found to be significantly lower. SLCH asymmetry showed the most significant relationship with motor performance, showing significant and moderate positive correlations with all performance tests. These findings suggest that functional asymmetries should be considered in terms of sport performance. Therefore, especially cross and side jump asymmetry are thought to be determinant in sports performance.