Bilateral difference in hamstrings to quadriceps ratio in healthy males and females

ObjectiveTo compare the isometric and isokinetic hamstrings to quadriceps (H:Q) ratio 1) between the dominant (D) and non-dominant (ND) legs, and 2) between healthy males and females.DesignCross-sectional.SettingUniversity research laboratory. Quadriceps and hamstrings strength were assessed by maximum isometric contractions at six angles (40°, 50°, 60°, 70°, 80°, 90°) and concentric contractions at three angular velocities (60° s−1, 180° s−1, 300° s−1).ParticipantsForty physically active adults (25 males).Main outcome measuresPeak isometric and isokinetic torques of the quadriceps and hamstrings, and the corresponding H:Q ratios.ResultsIsometric H:Q ratio increased with greater knee extension (P < 0.001), with overall a higher ratio in the D leg (P < 0.001). Isokinetic H:Q ratio increased with angular velocity (P < 0.001), with a higher ratio in the D leg (P < 0.05). Neither isometric nor isokinetic H:Q ratios differed between males and females.ConclusionsWhen setting rehabilitation goals, it may be appropriate to adjust the H:Q ratio and leg strength based on the uninvolved leg with consideration of leg dominance. Gender-related differences do not explain the discrepancy in the literature regarding bilateral differences in the H:Q ratio. Other subject characteristics such as age and training may be more relevant.