Effects of Resistance Training on Muscle Cross-sectional Area and Body Composition after Spinal Cord Injury

Abstract

Skeletal muscle atrophy, decreased fat-free mass (FFM) and increased fat mass (FM) are common adaptations in individuals with spinal cord injury (SCI). Evoked resistance training (RT) using neuromuscular electrical stimulation (NMES) and ankle weights to the paralyzed skeletal muscles has been shown to evoke significant hypertrophy. PURPOSE: To determine the effects of 12 weeks of NMES RT and diet when compared to diet only on skeletal muscle cross-sectional area (CSA), subcutaneous adipose tissue (SAT) CSA and body composition (FFM and FM). METHODS: Nine individuals with motor complete SCI (C5-T11, 35 ± 9 years, 22 ± 4 kg/m2) were randomly assigned into one of two groups; RT + diet (n= 5) or diet control (n=4). The RT+ diet underwent 12weeks of progressive RT of the right and left knee extensors muscle groups using NMES and ankle weights. Weekly feedback was provided to both groups to maintain a standard diet at 45% carbohydrate, 30% fat and 25% protein. T1 weighted magnetic resonance images of both thighs and whole body dual x-ray absorptiometry were acquired prior to and after training. Analysis of covariance was used to test for statistical difference. RESULTS: Prior to training, skeletal muscle CSAs of the whole thigh, knee extensors and knee flexors were not different in the RT + diet versus diet. Following training, skeletal muscle hypertrophy was detected in the whole thigh (77.5 ± 16 vs. 53 ± 26 cm2, P < 0.0001), knee extensors (35 ± 3 vs. 26 ± 13 cm2, P < 0.0001) and knee flexors (22 ± 8 vs. 16 ± 6 cm2, P < 0.0001) in the RT + diet group versus the diet group, respectively. The RT + diet group skeletal muscle CSA of the whole thigh, knee extensors and knee flexors increased by 28%, 35% and 16%, P < 0.0001, respectively; while no change was observed in the diet group. There were no significant changes in the thigh SAT or whole body composition in either group. CONCLUSION: Twice a week of Evoked RT to the paralyzed lower extremities resulted in significant skeletal muscle hypertrophy in individuals with SCI. However, the length of training was not sufficient to induce changes in whole body composition or SAT. Supported by Research Support Fund Grant from Indiana University