No Differences in Motor Units Discharge Rate Between Females and Males in Explosive Ankle Dorsiflexions.

Males and females exhibit comparable levels of explosive strength if the rate of torque development (RTD) is considered relative to the maximal voluntary isometric torque (MVT). Given the greater proportion of type I to type II fibers area in muscles of females than males (~20% in tibialis anterior muscle), with slower contractile kinetics, the discharge rate of motor units (MUDR) in explosive efforts may be higher to compensate for the slower muscle contractile properties. Yet, it is to date unknown whether sex differences in MUDR in explosive efforts exist. Twenty-two females and 12 males (20-34 years) performed electrically evoked and voluntary rapid isometric ankle dorsiflexions. Electrically evoked contractions consisted of three trains of 50 supramaximal stimuli at the common peroneal nerve at 200 Hz. Ten voluntary explosive contractions were then performed while recording high-density electromyography signals from the tibialis anterior. No significant differences were reported between males and females for both voluntary and electrically evoked relative peak RTD (8.0 ± 2.0 vs. 7.7 ± 0.8 and 6.4 ± 0.7 vs. 6.1 ± 2.1 MVT s