Limb Asymmetry Characteristics Amongst Men’s and Women’s NCAA Division II Soccer Athletes

Differences in the performance and function of one limb with respect to the other is known as interlimb asymmetry, while intralimb asymmetry deals with differences in muscle forces within the same limb. Both forms of asymmetry are common in the sport of soccer due to its distinct characteristics. These differences in strength between dominant and nondominant limbs or muscle groups may lead to increased injury rates in soccer athletes. The purpose of this study was to compare the magnitude of interlimb and intralimb asymmetry between NCAA Division II men’s and women’s soccer players. Thirty participants (male = 15, female =15) completed a testing protocol in which concentric knee extensor and flexor peak torque was measured. Three isometric contractions lasting five seconds each were completed by all participants for each action on the dominant and nondominant limb. Interlimb asymmetries were observed in each sex (Male: Quad (Q) = 10.62 ± 8.89%, Hamstring (H) = 13.33 ± 8.43%. Females: Q = 7.70 ± 7.63% H = 8.56 ± 6.04%) in both the Q and H muscle groups with the dominant limb being stronger. When comparing the sexes, males possessed significantly larger (p = 0.04) interlimb hamstring imbalances as compared to females. While females observed slightly elevated intralimb (H:Q) ratios for both limbs as compared to males, no significant differences were observed in H:Q ratio between the groups in the dominant (p = 0.485) or nondominant leg (p = 0.195). Results of interest indicate that male participants possessed significantly larger magnitude of interlimb imbalance as compared to females, and males may observe a greater benefit from focused training aimed at reducing interlimb asymmetries specifically in the hamstring group. This research only investigated isometric contractions which may pose as a limitation to the inference of results.