Coordinated muscle activity of the legs during assisted bilateral hip scillation in human spinal cord injury

The aim of this study was to investigate the role of supraspinal input on spastic reflex excitability in chronic human spinal cord injury (SCI). Muscle activity of ten subjects with a motor incomplete SCI was compared to the muscle activation patterns of control subjects with no neurological deficits during assisted and passive bilateral hip oscillations. There was a distinct difference between the timing of muscle activity patterns between SCI and control subjects. In addition, results suggest that remaining voluntary effort has little effect on spastic reflex responses in human SCI, evidenced by a similarity in the muscle activity measured during assisted and passive movements of the SCI subjects. These results have important implications in motor rehabilitation in people with SCI, suggesting that spastic reflexes can easily dominate control of movement.