Effects of dose de-escalation following testosterone treatment and evoked resistance exercise on body composition, metabolic profile, and neuromuscular parameters in persons with spinal cord injury.

The dose de-escalation (DD) effects of testosterone and evoked resistance training (RT) on body composition, cardiometabolic, and neuromuscular variables were investigated. Thirteen men with chronic complete spinal cord injury (SCI) were followed for additional 16 weeks after receiving either testosterone treatment only (TT) or TT+RT. During the 16-week DD period, the TT+RT group underwent a program of once weekly electrical stimulation with gradually decreasing ankle weights and testosterone patches of 2 mg day-1 (TT+RT group). The TT only group did not receive any intervention throughout the detraining period (no-TT group). Body composition was tested using anthropometrics, dual energy X-ray absorptiometry, and magnetic resonance imaging. After an overnight fast, basal metabolic rate (BMR), lipid panel, serum testosterone, inflammatory biomarkers, glucose effectiveness, and insulin sensitivity were measured. Finally, peak isometric and isokinetic torques were measured only in the TT+RT group. All measurements were conducted at the beginning and at the end of DD. Absolute thigh muscle cross-sectional areas (CSAs) demonstrated interaction effects (p < 0.05) between the TT+RT (-8.15%, -6.5%) and no-TT (2.3%, 4.4%) groups. Similarly, absolute knee extensor muscle CSA demonstrated interaction effects (p < 0.05) between the TT+RT (-11%, -7.0%) and no-TT (2.6%, 3.8%) groups. There was a trend (p = 0.07) of increasing visceral adipose tissue (VAT) CSAs in the TT+RT (18%) and in the no-TT (16% cm2 ) groups. There was an interaction (p = 0.005) between TT+RT (decreased by 3.7%) and no-TT groups (increased by 9.0%) in BMR. No interactions were evident between groups over time for biomarkers related to carbohydrate, lipid metabolism, or inflammation. Finally, there were no changes (p > 0.05) in peak isometric or isokinetic torques and rise time following 16 weeks of the DD period in the TT+RT group. TT+RT during 16 weeks of DD was minimally effective at preventing detraining relative to no-TT on muscle size, BMR, and VAT. However, neuromuscular gains were successfully maintained.