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

To 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.

Cross-sectional.

University research laboratory. Quadriceps and hamstrings strength were assessed by maximum isometric contractions at six angles (40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees) and concentric contractions at three angular velocities (60 degrees s(-1), 180 degrees s(-1), 300 degrees s(-1)).

Forty physically active adults (25 males).

Peak isometric and isokinetic torques of the quadriceps and hamstrings, and the corresponding H:Q ratios.

Isometric 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.

When 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.