Pilot study of the effect of low-cadence functional electrical stimulation cycling after spinal cord injury on thigh girth and strength

Abstract

Objective: To investigate the long-term effects of functional electrical stimulation (FES)-evoked cycle training cadence on leg muscle hypertrophy and electrically evoked strength.

Design: Open intervention study.

Setting: Laboratory setting.

Participants: Untrained individuals with chronic spinal cord injury (N=8).

Interventions: Six weeks (3d/wk) of training on an isokinetic FES cycle ergometer. For each subject, 1 leg was randomly allocated to cycling at 10 revolutions per minute (rpm) (LOW) for 30min/d, and the other cycling at 50rpm (HIGH) for 30min/d.

Main outcome measures: Pre- and posttraining measurements of lower limb circumference were performed at the distal and middle position of each thigh. Electrically evoked quadriceps muscle torque during an isometric contraction was also assessed.

Results: Six weeks of FES cycle training significantly increased thigh girth in both LOW and HIGH groups. At midthigh, girth increases induced by LOW (6.6%±1.2%) were significantly greater than those by HIGH (3.6%±0.8%). LOW also produced greater gains in electrically evoked isometric torque than HIGH after training.

Conclusions: These results suggest that lower pedaling cadences evoke greater muscle hypertrophy and electrically stimulated muscle strength compared with higher cadences.