Hamstrings to Quadriceps Torque Ratio in the Dominant and Non-Dominant Legs of Physically Active Individuals

Abstract

Hamstrings to quadriceps (H/Q) torque ratio is commonly used to assess the risk of injury in athletes and monitor the rehabilitation process. PURPOSE: To compare the H/Q torque ratio of the dominant (D) and non-dominant (ND) legs in physically active individuals. METHODS: Following IRB approval, 42 physically active subjects who exercised at least 3 times per week for 30 min or more (26 males; 16 females; mean ± SD: age 25.3 ± 5.9 yr; mass 72.8 ± 20.0 kg; height 1.72 ± 0.09 m) signed an informed consent and agreed to participate in the study. Participants performed maximum concentric knee extension and flexion exercises on an isovelocity dynamometer. Each test consisted of 5 repetitions at 60°/sec, 10 repetitions at 180°/sec and 15 repetitions at 300°/sec. The H/Q ratio was calculated from the peak concentric extension and flexion torque at each velocity. A repeated measures ANOVA (leg x velocity) was used to determine the difference in H/Q ratio in all participants and males and females separately. A 3-way ANO VA was used to examine the effects of sex (males / females), injury history (with / without previous lower extremity injuries) and types of activity (endurance sports / intermittent sports / fitness) on the H/Q ratio in the D and ND legs at the different velocities. RESULTS: The H/Q ratio was higher in the D leg than the ND leg (60°/sec: 53.8 ± 15.9 vs 50.1 ± 12.0, 180°/sec: 58.0 ± 14.9 vs 56.5 ± 15.5, 300°/sec: 64.4 ± 19.9 vs 57.0 ± 18.3) in the group as a whole (P < 0.05). This finding was consistent in females (P < 0.05) but not in males (P > 0.05). As the velocity increased, the H/Q ratio increased in the group as a whole, male and female (all groups: P < 0.05). However, there was no difference in the pattern of response between the D and ND legs in all groups. No significant differences were found in the H/Q ratio between males and females, individuals with and without previous injuries or individuals participating in different types of activities. CONCLUSIONS: The increase in H/Q ratio with velocity indicates that velocity should be considered when evaluating H/Q ratio. The higher H/Q ratio in the D leg at all velocities may question the use of H/Q ratio of the uninvolved limb as the rehabilitation goal of the involved limb.