Physiologic costs of reciprocal gait in FES assisted walking.

This study reports the velocity and physiologic cost index (PCI) of ambulation using a functional electrical stimulation (FES) system for ambulation in paraplegic spinal cord injured subjects. Using established techniques, average velocity and heart rate (HR) were measured on five subjects trained with the Parastep system. PCI was reported for the four subjects who achieved a steady state during ambulation with the Parastep system. It was found that walking performance varied greatly between subjects, and was correlated to frequency of use of the system. Velocity of walking with the Parastep system ranged from 4.6 to 24.3 m/min. In the four subjects where steady state was achieved, PCI ranged from 2.30 to 6.26 beats/m. The average walking speed and PCI were similar to the values reported using alternative mechanical or hybrid systems available to the spinal cord injured for restoration of upright locomotion.