Strength and endurance adaptations to functional electrical stimulation leg cycle ergometry in spinal cord injury

OBJECTIVES: To describe adaptations in power output, quadriceps muscle strength, and fatigability that occur during a 13-week regimen of Functional Electrical Stimulation Leg Cycle Ergometry (FES-LCE) in Spinal Cord Injury (SCI). To identify differences in outcomes between individuals with complete and incomplete motor impairment. DESIGN: Observational and longitudinal. SETTING: Rehabilitation and biomechanics research laboratory. PARTICIPANTS: Eleven (N=11) individuals with SCI and no previous FES-LCE experience. INTERVENTION: 40 sessions of FES-LCE at a rate of three sessions per week. Continuous exercise was performed at a pedal cadence of 45 RPM against a constant resistance for up to 60 minutes. OUTCOME MEASURES: Mean power output was recorded for each session. Before and after the training regimen, each subject performed a fatigue test in which electrically stimulated knee extension torque and Fatigue Index were measured. RESULTS: Participants demonstrated significant increases in mean power output (9.0 to 20.3 W; p < 0.001), peak isometric knee extension torque (3.8 to 16.9 Nm; p = 0.006) and sustainable isometric knee extension torque (4.9 to 14.4 Nm; p = 0.001) after FES-LCE training (95% confidence intervals). Participants with incomplete motor impairment demonstrated a decrease in Fatigue Index (p = 0.021), and improved mean power output more than those with complete motor impairment (p = 0.037). CONCLUSIONS: Significant improvements in muscle conditioning and exercise performance are possible following the 13-week regimen of FES-LCE described in this article. Individuals with incomplete motor impairment experience greater improvements in mean power output than individuals with complete motor impairment.