OBJECTIVETo investigate changes in body composition after 12 months of high-intensity progressive resistance training (PRT) in relation to changes in insulin resistance (IR) or glucose homeostasis in older adults with type 2 diabetes.RESEARCH DESIGN AND METHODSOne-hundred three participants were randomized to receive either PRT or sham exercise 3 days per week for 12 months. Homeostasis model assessment 2 of insulin resistance (HOMA2-IR) and glycosylated hemoglobin (HbA1c) were used as indices of IR and glucose homeostasis. Skeletal muscle mass (SkMM) and total fat mass were assessed using bioelectrical impedance. Visceral adipose tissue, mid-thigh cross-sectional area, and mid-thigh muscle attenuation were quantified using computed tomography.RESULTSWithin the PRT group, changes in HOMA2-IR were associated with changes in SkMM (r = −0.38; P = 0.04) and fat mass (r = 0.42; P = 0.02). Changes in visceral adipose tissue tended to be related to changes in HOMA2-IR (r = 0.35; P = 0.07). Changes in HbA1c were related to changes in mid-thigh muscle attenuation (r = 0.52; P = 0.001). None of these relationships were present in the sham group (P > 0.05). Using ANCOVA models, participants in the PRT group who had increased SkMM had decreased HOMA2-IR (P = 0.05) and HbA1c (P = 0.09) compared with those in the PRT group who lost SkMM. Increases in SkMM in the PRT group decreased HOMA2-IR (P = 0.07) and HbA1c (P < 0.05) compared with those who had increased SkMM in the sham group.CONCLUSIONSImprovements in metabolic health in older adults with type 2 diabetes were mediated through improvements in body composition only if they were achieved through high-intensity PRT.

We describe a method for obtaining skeletal muscle and subcutaneous adipose tissue in a single percutaneous needle biopsy procedure. Biopsies were performed in a double-blind randomized, sham-exercise controlled clinical trial of power training in 103 older adults with type 2 diabetes. In total 110 biopsies (73.3%) were performed in the first 50 participants at 3 time points. Muscle samples were obtained in 102/110 biopsies (92.7%); adipose samples were obtained in 72/110 biopsies (65.5%); both tissue types were obtained in 65/110 biopsies (59.1%). The average weight of muscle samples was 131±92 mg and the median weight of adipose samples was 51 mg (range 3 to 412 mg). No adverse effects of biopsies were reported other than mild transient pain or light-headedness. This is one of the first reports of both adipose and muscle tissue obtained during the same biopsy, and the first to describe in detail sampling technique, yield and safety

We sought to determine the effects of 12 months of power training on cognition, and whether improvements in body composition, muscle strength and/or aerobic capacity (VO2peak) were associated with improvements in cognition in older adults with type 2 diabetes (T2D). Participants with T2D were randomized to power training or low intensity sham exercise control condition, three days per week for 12 months. Cognitive outcomes included memory, attention/speed, executive function, and global cognition. Other relevant outcomes included VO2peak, strength, and whole body and regional body composition. One hundred and three adults with T2D (mean age 67.9 years; SD 5.9; 50.5% women) were enrolled and analyzed. Unexpectedly, there was a nearly significant improvement in global cognition (P=0.05) in the sham group relative to power training, although both groups improved over time (P&lt;0.01). There were significant interactions between group allocation and body composition or muscle strength in the models predicting cognitive changes. Therefore, after stratifying by group allocation, improvements in immediate memory were associated with increases in relative skeletal muscle mass (r=0.38, P=0.03), reductions in relative body fat (r=–0.40, P=0.02), and increases in knee extension strength were directly related to changes in executive function (r=–0.41, P=0.02) within the power training group. None of these relationships were present in the sham group (P&gt;0.05). Although power training did not significantly improve cognition compared to low-intensity exercise control, improvements in cognitive function in older adults were associated with hypothesized improvements in body composition and strength after power training.

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