A secondary analysis of testosterone and electrically evoked resistance training versus testosterone only (TEREX-SCI) on untrained muscles after spinal cord injury: a pilot randomized clinical trial.

STUDY DESIGN

Secondary analysis of a clinical trial.

OBJECTIVES

To perform a secondary analysis on the effects of neuromuscular electrical stimulation resistance training (RT) combined with testosterone replacement therapy (TRT) compared with TRT on the untrained muscles after spinal cord injury (SCI).

SETTING

Medical research center.

METHODS

Twenty-two men with chronic motor complete SCI were randomized into TRT + RT group (n = 11) or TRT group (n = 11). Both groups received 16 weeks of TRT (2-6 mg/day) via testosterone patches. The TRT + RT group received twice weekly progressive RT of the knee extensor muscles using electrical stimulation and ankle weights. Magnetic resonance images were captured to measure cross-sectional areas (CSAs) of trunk, glutei, and leg muscles.

RESULTS

Total and absolute gluteus maximus m. (14%, P = 0.003 and 16%, P = 0.001), gluteus medius m. (10%; P = 0.008 and 14%; P = 0.02), and total glutei m. (8%, P = 0.01 and 11%, P = 0.005) CSAs increased overtime for the TRT + RT group. Mean between-group differences of 2.86 (95% CI: 0.30, 5.4), 1.89 (95% CI: 0.23, 3.58) and 5.27 (95% CI: 0.90, 9.69) cm were noted for absolute gluteus maximus, total gluteus medius and total glutei CSAs, respectively (P < 0.05). Trunk muscle CSAs showed a trend towards an interaction between groups.

CONCLUSIONS

RT combined with low-dose TRT results in significant hypertrophy compared with TRT only on the adjacent untrained glutei muscles. Trunk muscles may require direct stimulation to evoke hypertrophy. These exploratory findings may be of clinical relevance in the reduction of incidence and severity of pelvic pressure injuries.