The Effects of Two Different Stretching Programs on Balance Control and Motor Neuron Excitability

Abstract

We examined the effects of training (4d/wk for 6 wks) with static stretching (SS) or contract-relax proprioceptive neuromuscular facilitation (PNF) on static balance time and motor neuron excitability. Static balance time, H_max/M_max ratios and H-reflex recovery curves (HRRC) were measured in 28 healthy subjects (SS: n=10, PNF: n=9, control: n=9) before and after training. SS improved static balance time with a trend observed for PNF. Post training, during 150-200-250 msec interstimulus intervals, we observed a reduction in facilitation, but during 500-700-900 msec interstimulus interval; there was an increase in H2/H1 ratio in the PNF group only. Both stretching techniques improved static balance. The Ia afferent inhibitions during the acute exercises were not found after the SS and PNF training programmes. It was concluded that training with contract-relax proprioceptive neuromuscular facilitation may cause some augmentation in supraspinal and postsynaptic inhibition on the motoneuron pool.