Peak exercise capacity of electrically induced ambulation in persons with paraplegia

Persons with spinal cord injury (SCI) are generally limited to exercise activities using the relatively smaller, less productive upper extremities with limited benefits as compared with leg exercise training. Functional electrical stimulation (FES) assisted ambulation has previously been demonstrated to allow persons with paraplegia to stand and ambulate limited distances.

This study compared the peak physiological responses of persons with paraplegia during FES ambulation and voluntary arm exercise.

Fifteen subjects (T -T ) previously habituated to FES ambulation, completed peak testing of both arm cranking (AC) and FES walking to the point of exhaustion. The AC tests were performed using a graded incremental protocol to exhaustion in 3-min stages and 10-W power output increments. The FES walking test consisted of successive 10-m walking bouts, each trial progressively increased in pace. Metabolic activity was continuously monitored via open-circuit spirometry with heart rate (HR) determined by a 12-lead electrocardiograph for AC and by direct palpation during FES.

Peak VO(2) did not differ between AC (22.9 +/- 3.8 mL x kg x min(-1)) and FES (22.7 +/- 3.9 mL x kg x min(-1)). FES ambulation elicited significantly greater peak values of HR (191 beats x min(-1) versus 179 beats x min(-1)) and lower peak values of respiratory exchange ratio (1.06 vs 1.12) compared with AC. There were no significant differences in peak values of any other variables.

This study indicates that FES ambulation performance, in persons with paraplegia, elicits similar exercise capacity, as indicated by similar peak oxygen consumption, as voluntary arm exercise.