Effects of limb loading on the lower-limb electromyographic activity during orthotic locomotion in a paraplegic patient

The relationship between limb loading and lower-leg electromyographic (EMG) activity was examined during orthotic locomotion in a complete paraplegic patient. The level of limb loading was modified by a hanging system. Surfac e EMG in the lower-leg extensor and flexor muscles was unilaterally recorde d together with the load signal on the ipsilateral sole. The motion of the knee and the ankle joints was minimized, which means that the change in len gth of the examined muscles was minimum. The muscles were activated synchro nously with the locomotor movement and the magnitude of the extensor activi ty was changed relative to the peak load on the sole. It is conceivable tha t the spinal cord interpreted the load information and modified the EMG out put in the anti-gravity muscles even in the absence of stretch reflexes. (C ) 1999 Elsevier Science ireland Ltd. All rights reserved.