The Relationship Between Competition Level and Dynamic Balance in Male and Female Soccer Players

PURPOSE: To investigate the relationship between competition level and sex differences with dynamic balance in soccer players. METHODS: Over a 15 year period, preseason screenings were performed including limb length, activity scale, sport and the Y-Balance Test Lower Quarter (YBT-LQ). The maximum distance for the anterior (ANT), posteromedial (PM), and posterolateral (PL) reaches were normalized to limb length. Reach asymmetry and composite score were calculated. Unadjusted and adjusted multivariable quantile regressions, with coefficients and 95% confidence intervals (95% CI), were performed to investigate the relationship between competition and dynamic balance. Sensitivity analyses were performed for left and right limbs. Mann Whitney U tests and Cohen’s D effect size indices (ES) with 95% CI’s were performed to examine male and female YBT-LQ reach asymmetry differences. RESULTS: 5,018 participants (Age: 16.6 [3.6] years; Males: 2,484, Females: 2,533; ANT: 64.3 [8.14], PM: 96.6 [11.5], PL: 97.9 [11.6], Composite: 98.0 [9.2]) were included. There was a negative adjusted relationship between ANT and female (-0.27 [-0.55, -0.13]). There was a positive adjusted relationship between age and PL (0.43, [0.19, 0.67]), PM [0.49, (0.22, 0.76]), and composite (0.39, [0.32, 0.47]). There was a negative adjusted relationship for ANT (-0.27, [-0.55, -0.13]) in females and a positive adjusted relationship for PL (0.49 [0.22, 1.04]) and PM (0.93 [0.45, 1.38]). A positive relationship for age and composite score for females (0.36 [0.28, 0.57]), but not males (0.09 [-0.10, 0.37]). There were significant differences in PL and PM, however, the effect sizes were small ([p = <0.05], ES: 0.08-0.12). CONCLUSIONS: As soccer players get older their dynamic balance improves for PM, PL, and composite scores on the YBT-LQ; however, ANT does not. Interestingly, females’ ANT decreased with age, but males did not change. Females composite score increased until age 14 and then precipitously dropped between ages of 15-17. Sex may affect dynamic balance, especially in ANT and composite scores. This may indicate a relationship between dynamic balance and onset of puberty which needs to be further studied.