Effect of Speed and Gender on Rate of Velocity Development Quadriceps/Hamstrings Ratios

Abstract

PURPOSE: There is speculation that the ratio of quadriceps to hamstrings rate of velocity development (RVD) differs between genders and speeds due to the male bias in limb movement speed. The purpose of this study was to determine if males and females demonstrated different lower body muscle group RVD ratios when testing across a velocity spectrum. METHODS: 119 male (n=57) and female (n=62) university kinesiology students (age 23.29±2.13 years, height 170.98±10.25 cm, weight 71.29±16.15 kg) performed 5 maximal reciprocal concentric/concentric knee extension and flexion repetitions on a Biodex System 3 isokinetic dynamometer at 13 random speeds between 30 and 400 d/s. RVD is the measured ROM traveled from 0 to the target velocity, therefore, a lower value equates to greater limb acceleration. Quadriceps/hamstrings ratios were determined by dividing peak extension RVD by peak flexion RVD and multiplying by 100. ANOVA was used to determine the differences between male and female ratios, as well as the differences of the ratios across the velocity spectrum. RESULTS: Males and females demonstrated no significant differences in peak quadriceps/hamstrings RVD ratios when compared across speeds. However, there was a significant (p <0.05) main effect for speed on the RVD ratios. As testing speeds increased, the quadriceps/hamstrings RVD ratios decreased. Ratios decreased from 76.97%+19.31 to 64.10%+6.73 between 30 and 400 d/s respectively. CONCLUSION These results demonstrate that although males had less RVD at all speeds, there was no difference in RVD ratios by gender. The data also indicate that peak RVD in the hamstrings and quadriceps increases with increasing velocity while the ratios decline. This is due to the fact that the hamstrings slow down at a greater rate than the quadriceps causing the ratio to decrease. This is contrast to the increasing ratios seen in torque development. Therefore, training protocols may need to be moderated at very high velocities to insure that hamstring exercise is within the velocity range capability.