Sex differences in the rate of torque development and torque-velocity relationship are due to maximal strength only

This study aimed to analyse the sex differences in the rate of torque development (RTD) and torque-velocity parameters with and without normalisation for maximal voluntary torque (MVT).

Right-leg knee extensors were tested in 64 healthy and active participants (31 F and 33 M). MVT and RTD were obtained under isometric conditions. Individual torque-velocity relationships were obtained using a curvilinear model on averaged torque and velocity over 80°-to-140° knee angle. Dynamic data were acquired through an incremental protocol on a leg extension machine, going from the lightest to the unmovable load despite maximal effort.

Independent samples t test revealed (p < 0.001) that males possess greater RTD measured at 50 ms (d = -1.2), 100ms (d = -2.1) and 150ms (d = -2.3), peak RTD (d = -1.3) and MVT (d = 2.1). When normalised by MVT, the sex differences in RTD disappeared. Curvilinear hyperbolic TV relationship well-fitted (R² = 0.99). In FV parameters, maximal theoretical torque (d = -1.7), maximal power (P_max) (d = -2.0), and torque at P_max (d = -1.7) were greater in males (p < .05), while maximal theoretical velocity (V₀) and velocity at P_max did not differ.

The sex differences in explosiveness (i.e., rapid isometric and dynamic force production) were mainly due to greater maximal strength in males than in females. These findings suggest that, in non-sedentary people, males do not present higher contraction velocity capacities, i.e. higher maximal velocity until which muscles can produce force, than females in knee extension.