Effects of increasing walking speed on ankle muscle co-contraction based on spasticity severity in chronic stroke patients

Plantar flexor muscles produce propulsive force in the second half of stance phase; deficient motor output from these muscles would lead to inadequate propulsion at push off phase of gait following stroke. The aim of the present study was to examine the effects of walking on a treadmill at varying speeds on ankle muscle activation in stroke survivors and to compare the effect of increasing speed on plantar flexor muscle activity in subject groups in relation to spasticity severity.
Nineteen stroke survivors (13M/6F) walked on a standard treadmill at three different speeds (self-selected, self-selected%, self-selected%). The electromyographic activity of Medial Gastrocnemius (MG), and Tibialis anterior (TA) muscles recorded at push off phase of the gait.
In the high spasticity subgroup (Tardieu scale ≥2), paretic MG activity increased as walking speed increased (p Our data indicates that individuals with stroke can be safely trained on a treadmill to walk 20-40% above the self-selected pace to improve MG output without adversely affecting TA output.