Electrically induced resistance training in individuals with motor complete spinal cord injury.

Objective: To examine the effects of 16 weeks of electrically induced resistance training on insulin resistance and glucose tolerance, and changes in muscle size, composition, and metabolism in paralyzed muscle.

Design: Pre-post intervention.

Setting: University-based trial.

Participants: Participants (N=14; 11 men and 3 women) with chronic (>2y post spinal cord injury), motor complete spinal cord injury.

Intervention: Home-based electrically induced resistance exercise training twice weekly for 16 weeks.

Main Outcome Measures: Plasma glucose and insulin throughout a standard clinical oral glucose tolerance test, thigh muscle and fat mass via dual-energy x-ray absorptiometry, quadriceps and hamstrings muscle size and composition via magnetic resonance imaging, and muscle oxidative metabolism using phosphorus magnetic resonance spectroscopy.

Results: Muscle mass increased in all participants (mean ± SD, 39%±27%; range, 5%-84%). The mean change ± SD in intramuscular fat was 3%±22%. Phosphocreatine mean recovery time constants ± SD were 102±24 and 77±18 seconds before and after electrical stimulation-induced resistance training, respectively (P<.05). There was no improvement in fasting blood glucose levels, homeostatic model assessment calculated insulin resistance, 2-hour insulin, or 2-hour glucose.

Conclusions: Sixteen weeks of electrical stimulation-induced resistance training increased muscle mass, but did not reduce intramuscular fat. Similarly, factors associated with insulin resistance or glucose tolerance did not improve with training. We did find a 25% improvement in mitochondrial function, as measured by phosphocreatine recovery rates. Larger improvements in mitochondrial function may translate into improved glucose tolerance and insulin resistance.