Changes in skeletal muscle size and glucose tolerance with electrically stimulated resistance training in subjects with chronic spinal cord injury

Objective: To determine the effect of residence-based, resistance exercise training (RET) on affected skeletal muscle size and glucose tolerance after long-standing, complete spinal cord injury (SCI). Design: Before-after trial. Setting: University laboratory trial. Participants: Five men with chronic, complete SCI (C5-T9). Intervention: Magnetic resonance images of the thighs and an oral glucose tolerance test were performed before and after RET. Subjects performed RET with both thighs, 2d/wk for 4 sets of 10 unilateral, dynamic knee extensions for 12 weeks. Neuromuscular electric stimulation induced RET by activating the knee extensors. Main Outcome Measures: Quadriceps femoris muscle cross-sectional area (CSA), plasma glucose, and insulin concentrations were measured before and after RET. Results: Skeletal muscle CSA increased by 35% in the right quadriceps femoris (from 32.6cm(2) to 44.0cm(2)) and by 39% in the left quadriceps femoris (from 34.6cm(2) to 47.9cm(2)) as a result of training (P <.05). There were no significant changes in blood glucose or insulin after training. However, a trend for a reduction in plasma glucose levels was observed (P=.074). Conclusions: Affected skeletal muscle can achieve substantial hypertrophy years after SCI with resistance exercise. Furthermore, our results suggest that this type of training may enhance glucose disposal.