Effect of lower extremity functional electrical stimulation pulsed isometric contractions on arm cycling peak oxygen uptake in spinal cord injured individuals

Abstract

<p><i>Objective - </i>To compare peak oxygen uptake (VO_2peak) between: (<i>i</i>) functional electrical stimulation lower extremity pulsed isometric muscle contractions combined with arm cycling (FES iso hybrid), (<i>ii</i>) functional electrical stimulation cycling combined with arm cycling (FES hybrid cycling), and (<i>iii</i>) arm cycling exercise (ACE) in individuals with spinal cord injury with level of injury above and below T6. <p><i>Design - </i>Cross-over repeated measures design. <p><i>Methods/participants - </i>Individuals with spinal cord injury (<i>n</i> = 15) with level of injury between C4 and T12, were divided into groups; above (spinal cord injury – high, <i>n</i> = 8) and below (spinal cord injury – low, <i>n</i> = 7) T6 level. On separate days, VO_2peak was compared between: (<i>i</i>) ACE, (<i>ii</i>) FES iso hybrid, and (<i>iii</i>) FES hybrid cycling. <p><i>Results - </i>In the SCI–high group, FES iso hybrid increased VO_2peak (17.6 (standard deviation (SD) 5.0) to 23.6 (SD 3.6) ml/kg/min; <i>p</i> = 0.001) and ventilation (50.4 (SD 20.8) to 58.2 (SD 20.7) l/min; <i>p</i> = 0.034) more than ACE. Furthermore, FES hybrid cycling resulted in a 6.8 ml/kg/min higher VO_2peak (<i>p</i> = 0.001) and an 11.0 litres/minute (<i>p</i> = 0.001) higher ventilation. ACE peak workload was 10.5 W (<i>p</i> = 0.001) higher during FES hybrid cycling compared with ACE. In the spinal cord injury – low group, no significant differences were found between the modalities. <p><i>Conclusion - </i>VO_2peak increased when ACE was combined with FES iso hybrid or FES hybrid cycling in persons with spinal cord injury above the T6 level. Portable FES may serve as a less resource-demanding alternative to stationary FES cycling, and may have important implications for exercise prescription for spinal cord injury.