Gains in aerobic capacity with whole-body functional electrical stimulation row training and generalization to arms-only exercise after spinal cord injury

STUDY DESIGN: Longitudinal study in adults (n=27; 19–40 years old) with tetraplegic or paraplegic spinal cord injury (SCI). OBJECTIVES: Determine physiological adaptations and generalizable fitness effects of six months of whole-body exercise training using volitional arm and functional electrical stimulation (FES) leg rowing. SETTING: Outpatient hospital-based exercise facility and laboratory METHODS: Participants enrolled in hybrid FES row training (FESRT) and performed peak exercise tests with arms-only (AO; baseline and 6-Mo) and FES rowing (baseline, 3-Mo, 6-Mo). RESULTS: Participants demonstrated increased aerobic capacity (VO(2peak)) after FESRT (p<0.001, n(p)(2)=0.56) that tended to be higher when assessed with FES than AO rowing tests (0.15 ± 0.20 vs. 0.04 ± 0.22 L/min; p=0.10). Changes in FES and AO VO(2peak) were significantly correlated (r=0.55; p<0.01), and 11 individuals demonstrated improvements (>6%) on both test formats. Younger age was the only difference between those who showed generalization of training effects and those who did not (mean age 26.6 ± 5.6 vs. 32.0 ± 5.7 years; p<0.05) but changes in FES VO(2peak) correlated to time since injury in individuals <2 years post-SCI (r=−0.51, p<0.01, n=24). Lastly, VO(2peak) improvements were greater during the first three months vs. months 4–6 (+7.0% vs. +3.9%; p<0.01) which suggests early training adaptations during FESRT. CONCLUSIONS: Gains in aerobic capacity after whole-body FESRT are better reflected during FES row testing format. They relate to high-intensity exercise and appear early during training, but they may not generalize to equivalent increases in AO exercise in all individuals with SCI.