Lower Limb´S Lateral And Functional Asymmetries And Mechanical Performance In Professional Soccer Players

PURPOSE: As reported in the medical literature, lateral asymmetries (LA) in sports may lead to overload injuries and reduction in performance. Even a lateral asymmetry of ten percent can lead to structural and functional conditions which may precipitate sub-optimal performance or increase the risk of overload injuries. The aim of this study was to explore the influence of lateral lower extremity asymmetries in both functional and mechanical performance METHODS: We evaluated the lower limb LA of sixty-four Costa Rican professional soccer players (age 20 ± 4.3 years, weight 70.9 ± 7.3 kg, height 174.6 ± 4.9 cm, fat 13.9 ± 5 %). LA in lean mass (LM; kg), time of contraction (Tc) and muscle displacement (Dm) of both right and left lower limbs were evaluated. Anthropometry was measured using dual X-ray absorptiometry. Functional performance was assessed through countermovement jump (CMJ) and squat jump (SJ) using a force platform and mechanical performance was assessed measuring rectus femoris Tc and Dm using a tensiomyography. Pearson correlations between LA and CMJ, SJ, Tc and Dm were performed. Significance was previously set at p < 0.05. Lateral asymmetry was calculated as follows: [(higher score- lower score) / higher score) x100]; considering a 10% difference as significant asymmetry. RESULTS: There were no significant correlations between LA and CMJ (LA-LM, p = 0.44; LA-Tc, p = 0.46; LA-Dm, p = 0.88), SJ (LA-LM, p = 0.81; LA-Tc, p = 0.99; LA-Dm, p = 0.97), R-Tc (LA-LM, p = 0.22; LA-Tc, p = 0.43; LA-Dm, p = 0.67), L-Tc (LA-LM, p = 0.323; LA-Tc, p = 0.897; LA-Dm, p = 0.528), R-Dm (LA-LM, p = 0.76; LA-Tc, p = 0.612) or L-Dm (LA-LM, p = 0.195; LA-Tc, p = 0.56; LA-Dm, p = 0.284). CONCLUSIONS: Lateral asymmetries in lower limbs do not appear to exert a positive or negative influence on functional or mechanical performance in Costa Rican soccer players.