Physiologic effects of functional electrical stimulation-induced exercises in spinal cord-injured individuals

Spinal cord injury (SCI) results in multiple degenerative changes that may in part be related to physical inactivity. There are indications that some of these changes may be reversed by exercise and fitness training. Computerized functional electrical stimulation (FES) allows active exercise of limbs paralyzed by upper motor neuron lesions. Thirty SCI subjects safely participated in an FES-induced exercise program for lower extremity strengthening and endurance training. Increased strength, endurance, and bulk of stimulated muscles were noted. The subjects were able to perform a greater amount of work on a lower extremity ergometer, both per unit of time and per length of time, indicating a training effect. A multistage stress test showed evidence that the subjects had increased their aerobic metabolism during the training program. Twitch time tests showed slowing of muscle contraction, and computed tomography showed increased muscle density.