Inter-Limb Symmetry Characteristics Among Male and Female Athletes – A Systematic Review

OBJECTIVES: (1) To summarize the literature, (2) determine sex differences, and (3) determine the changes under exercise-induced fatigue, in biomechanical lower limb inter-limb asymmetries in healthy adult male and female athletes, including those with a history of injuries. LITERATURE SEARCH: We searched MEDLINE, Web of Science, EMBASE, and CINHAL databases from inception to March 7, 2025 (Prospero number: CRD42023417697). STUDY SELECTION: Studies were included if they assessed lower limb inter-limb biomechanical asymmetry, compared, or reported biomechanical values for both lower limbs in adult male and female athletes. RESULTS: Sixty-four studies (5,837 athletes) were included. Forty studies compared sex-specific asymmetries. Fourteen studies reported significant sex differences in healthy athletes in asymmetry in hip abductor strength, explosive power, and kinetic measures commonly in females, as well as in quadriceps and hamstring strength in both males and females, while eleven studies found no sex differences. Five studies investigated asymmetries in healthy athletes with a history of injuries and reported sex differences in explosive power, and no sex differences for balance and knee muscle strength. Asymmetry in explosive power was more commonly noted in female healthy athletes (peak power [Females 17.21 (0.07) > males (12.81 (0.06)] P<0.05, effect size = 0.33) and healthy athletes with a history of injury (asymmetry (%) [males 95.4%, P = 0.003; females 96.5%, P = 0.049]). A meta-analysis was not performed due to study heterogeneity. No studies assessed sex-specific asymmetry under exercise-induced fatigue. CONCLUSION: Sex-specific biomechanical lower limb asymmetry remains inconsistent, with generally no sex differences except asymmetry in explosive power, which is more commonly reported in female athletes. High-quality studies are needed to address these gaps.