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Introduction: Severe burns result in prolonged hypermetabolism and skeletal muscle catabolism. Rehabilitative exercise training (RET) programs improved muscle mass and strength in severely burned children. The combination of RET with A-blockade or testosterone analogs showed improved exercise-induced benefits on body composition and muscle function. However, the effect of RET combined with multiple drug therapy on muscle mass, strength, cardiorespiratory fitness, and protein turnover are unknown. In this placebo-controlled randomized trial, we hypothesize that RET combined with oxandrolone and propranolol (Oxprop) will improve muscle mass and function and protein turnover in severely burned children compared with burned children undergoing the same RET with a placebo. Methods: We studied 42 severely burned children (7-17 yr) with severe burns over 30% of the total body surface area. Patients were randomized to placebo (22 control) or to Oxprop (20) and began drug administration within 96 h of admission. All patients began RET at hospital discharge as part of their standardized care. Muscle strength (NIm), power (W), ...O2peak, body composition, and protein fractional synthetic rate and fractional breakdown rate were measured pre-RET (PRE) and post-RET (POST). Results: Muscle strength and power, lean body mass, and ...O2peak increased with RET in both groups (P < 0.01). The increase in strength and power was significantly greater in Oxprop versus control (P < 0.01), and strength and power was greater in Oxprop over control POST (P < 0.05). Fractional synthetic rate was significantly higher in Oxprop than control POST (P < 0.01), resulting in improved protein net balance POST (P < 0.05). Conclusions: Rehabilitative exercise training improves body composition, muscle function, and cardiorespiratory fitness in children recovering from severe burns. Oxprop therapy augments RET-mediated improvements in muscle strength, power, and protein turnover. [ABSTRACT FROM AUTHOR]

Introduction: Loss of mitochondrial competency is associated with several chronic illnesses. Therefore, strategies that maintain or increase mitochondrial fimction will likely be of benefit in numerous clinical settings. Endurance exercise has long been known to increase mitochondrial function in the skeletal muscle. Comparatively little is known regarding the effect of resistance exercise training (RET) on skeletal muscle mitochondrial respiratory function. Purpose: The purpose of tire current study was to determine tire effect of chronic resistance training on skeletal muscle mitochondrial respiratory capacity and function. Methods: Here, we studied the effect of a 12-wk RET program on skeletal muscle mitochondrial function in 11 young healthy men. Muscle biopsies were collected before and after the 12-wk training program, and mitochondrial respiratory capacity was determined in permeabilized myofibers by high-resolution respirometry. Results: RET increased lean body mass and quadriceps muscle strength by 4% and 15%, respectively (P < 0.001). Coupled mitochondrial respiration supported by complex I, and complex I and II substrates increased by 2- and 1.4-fold, respectively (P < 0.01). The ratio of coupled complex I-supported respiration to maximal respiration increased with RET (P < 0.05), as did complex I protein abundance (P < 0.05), whereas the substrate control ratio for succinate was reduced after RET (P < 0.001). Transcripts responsible for proteins critical to electron transfer and NAD+ production increased with training (P < 0.05), whereas transcripts involved in mitochondrial biogenesis were unaltered. Conclusions: Collectively, 12 wk o f RET resulted in qualitative and quantitative changes in skeletal muscle mitochondrial respiration. This adaptation was accompanied by modest changes in mitochondrial proteins and transcript expression. RET seems to be a means to augment the respiratory capacity and intrinsic function of skeletal muscle mitochondria. [ABSTRACT FROM AUTHOR]

Severe bum trauma results in persistent skeletal muscle catabolism and probnged immobilization. We hypothesize that structured rehabilitative exercise is a safe and efficacious strategy to restore lean body mass and physical function in bum victims. Here, we review the evidence for the utility of rehabilitative exercise training in restoring physiological function in bum survivors. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to determine the effects of early outpatient exercise on muscle mass, function, and fractional synthetic rate in severely burned children. Methods: Forty-seven children with ≥40% total body surface area bum performed a 12-wk standard of care rehabilitation (SOC, n = 23) or rehabilitative exercise training (RET, n = 24) immediately after hospital discharge. Dual-energy x-ray absorptiometry was used to assess lean body mass (LBM) at discharge, posttreatment, and 12 months post-bum. Muscle function was evaluated with a Biodex Isokinetic Dynamometer, and peak aerobic fitness (VO2peak) was measured using a modified Brace treadmill protocol posttreatment. Stable isotope infusion studies were performed in a subset of patients (SOC, n = 13; RET, n= 11) at discharge and posttreatment to determine mixed-muscle fractional synthetic rate. Results: Relative peak torque (RET, 138 ± 9 N•m•kg−1, vs SOC, 106 ± 9 N•m•kg−1) and VO2peak (RET, 32 ± 1 mL•kg−1, vs SOC, 28 ± 1 mL•kg−1•min−1) were greater at posttreatment with RET compared with those with SOC. In addition, RET increased whole-body (9% ± 2%) and leg (17% ± 3%) LBM compared with SOC. Furthermore, the percentage change in whole-body (18% ± 3%) and leg (31% ± 4%) LBM from discharge to 12 months post-bum was greater with RET compared to SOC. Muscle fractional synthetic rate decreased from discharge to posttreatment in both groups (6.9% ± 1.1% per day vs 3.4 ± 0.4% per day); however, no differences were observed between treatment groups at each time point. Conclusions: Early outpatient exercise training implemented at hospital discharge represents an effective intervention to improve muscle mass and function after severe bum injury. [ABSTRACT FROM AUTHOR]