Assessment Of Lower Limb Asymmetries In Soccer Players According To The Stage Of The Season

PURPOSE: Muscle asymmetries can be associated with increased risk of injury. Using countermovement jump (CMJ) to analyze muscular asymmetries in the lower limbs of soccer players, according to the stage of the season. METHODS: Forty-eight male soccer players (age = 20.5 ± 4.5 years; height = 1.78 ± 5.6 cm; body mass = 71.9 ± 5.8 kg; body mass index = 22.7 ± 1.36; sports experience: 14 ± 4.1 years) were studied. The CMJ was measured by OptoGait® measurement system (Microgate®, Italy). Bilateral and unilateral CMJ were performed on both legs; flight time (FT) and jump height (JH) were measured. All measures were obtained at three different times during the season. Descriptive and bivariate statistical analyses were performed to test the correlation between the different recording moments. RESULTS: Significant differences were found in the FT (bilateral) when comparing pre-season with mid-season (r = 0.68, p = 0.01). With respect to JH, a significant difference was found between the pre-season and mid-season with the right leg (r = 0.78, p = 0.02), similar to comparing both moments with respect to bilateral height (r = 0.67, p = 0.01). With respect to the asymmetry between each leg in relation to FT, significant differences were found between end of the season (r = 0.76, p = 0.01) and pre-season (r = 0.80, p = 0.01), with no significant differences at the middle of the season (r = 0.51, p = 0.61). In relation to JH there were significant differences during pre-season (r = 0.79, p = 0.01), mid-season (r = 0.80, p = 0.01) and at the end of the season between both legs (r = 0.77, p = 0.01). CONCLUSIONS: There is a greater probability of asymmetries in the preseason and at the end of the season in relation to flight time and at all three stages of the season in relation to jump height. Based on these results, evaluation using countermovement jump at different stages of the season enables the detection of muscle asymmetry, which can be a risk factor for injury. Therefore, asymmetries should be evaluated through functional assessment tests to implement individualized training and injury prevention strategies.