Abstract:
Activity‐related knee joint dysfunction is more prevalent in females than males. One explanation
for the discrepancy is differences in movement patterns between the sexes. However the underlying
mechanisms responsible for these differences remain unidentified. This study tested spinal motor
control mechanisms influencing motor neuron pool output and subsequent muscle activation in 17
males and 17 females. The following variables were assessed at the soleus: the gain of the
unconditioned H‐reflex, gain of both intrinsic pre‐synaptic inhibition (IPI) and extrinsic pre‐synaptic
inhibition (EPI), the level of recurrent inhibition (RI), the level of supraspinal drive determined by the
ratio of the Vmax:Mmax, electromechanical delay (EMD) and rate of force development (RFD). The Wilks
Lambda multivariate test of overall differences among groups was significant (p=0.031). Univariate
between‐subjects tests revealed males had greater RI (p=0.042). However, the sexes not differ on any of
the other variables tested. In conclusion, the sexes differ on modulation of spinal motor control.
Specifically, RI, a post‐synaptic regulator of force output, was greater in males.
