Effects of prolonged muscle stretch on reflex and voluntary muscle activations in children with spastic cerebral palsy

Abstract

We studied the short term effects of a single session of prolonged muscle stretch (PMS) on reflex and voluntary muscle activations in 22 children with spastic cerebral palsy (CP) assigned to an experimental (n=12) and a control group (n=10). Children of the experimental group underwent PMS of the triceps surae (TS) by standing with the feet dorsiflexed on a tilt-table for 30 min, whereas children of the control group were kept at rest. The effects were determined by measuring the associated changes in torque and in electromyographic (EMG) activity of the TS and tibialis anterior (TA) muscles during both passive ankle movements and maximal static voluntary contractions. The results indciate that PMS led to reduced spasticity in ankle muscles as demonstrated by the significant reductions (p<0.05) of the neuromuscular responses (torque and EMG) to passive movement. These inhibitory effects lasted up to 35 min after cessation of PMS. In addition, the capacity to voluntarily activate the plantar flexors was significantly (p<0.05) increased post-PMS, but the capacity to activate the dorsiflexors was apparently not affected. These findings suggst that repeated sessions of PMS may have beneficial effects in the management of spasticity in children with CP.