Hamstrings to quadriceps peak torque ratios diverge between sexes with increasing isokinetic angular velocity

Our purpose was to determine if females demonstrate decreased hamstrings to quadriceps peak torque (H/Q) ratios compared to mates and if H/Q ratios increase with increased isokinetic velocity in both sexes. Maturation disproportionatety increases hamstrings peak torque at high velocity in mates, but not females. Therefore, we hypothesised that mature females would demonstrate decreased H/Q ratios compared to mates and the difference in H/Q ratio between sexes would increase as isokinetic velocity increased. Studies that analysed the H/Q ratio with gravity corrected isokinetic strength testing reported between 1967 and 2004 were included in our review and analysis. Keywords were hamstrings/quadriceps, isokinetics, peak torque and gravity corrected. Medline and Smart databases were searched combined with cross-checked bibliographic reference lists of the publications to determine studies to be included. Twenty-two studies were included with a total of 1568 subjects (1145 mate, 423 female). Mates demonstrated a significant correlation between H/Q ratio and isokinetic velocity (R = 0.634, p < 0.0001), and a significant difference in the isokinetic H/Q ratio at the lowest angular velocity (47.8 +/- 2.2% at 30 degrees/s) compared to the highest velocity (81.4 +/- 1.1% at 360 degrees/s, p < 0.001). In contrast, females did not demonstrate a significant relationship between H/Q ratio and isokinetic velocity (R = 0.065, p = 0.77) or a change in relative hamstrings strength as the speed increased (49.5 +/- 8.8% at 30 degrees/s; 51.0 +/- 5.7% at 360 degrees/s, p = 0.84). Gender differences in isokinetic H/Q ratios were not observed at slower angular velocities. However, at high knee flexion/extension angular velocities, approaching those that occur during sports activities, significant gender differences were observed in the H/Q ratio. Females, unlike mates, do not increase hamstrings to quadriceps torque ratios at velocities that approach those of functional activities. (c) 2007 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.