The impact of joint angle and movement velocity on sex differences in the functional hamstring/quadriceps ratio

Abstract

Background: Females are two to eight times more likely to suffer a non-contact injury compared with males thus the purpose of this study was to explore the influence of joint angle and movement velocity on sex differences in the functional hamstring to quadriceps ratio (H/Q_FUNC).

Methods: Isokinetic concentric and eccentric torque were determined in 110 participants (55 males and 55 females) through a 90° range of movement at 60, 120, and 240°/s. Testing was performed with the hip flexed at 10°. The H/Q_FUNC was determined at three specific joint angles (15, 30 and 45° flexion) and where peak torque occurred for concentric knee extension.

Results: A significant interaction effect (P<0.01) for sex and joint angle was observed with women demonstrating a lower H/Q_FUNC than males, especially at more extended knee positions. A significant sex by velocity interaction (P<0.01) indicated a lower H/Q_FUNC in women as velocity increased. Significant main effects (P<0.01) indicated that irrespective of sex the H/Q_FUNC increased as the knee extends and velocity increases.

Conclusion: Given the reduced H/Q_FUNC in females compared to males at more extended knee positions and faster velocities, this may contribute to the observed sex bias in reported injury rates.

Keywords: Functional H/Q ratio; Injury risk; Joint angle; Movement velocity; Sex differences.