Twice-Weekly Progressive Resistance Training Decreases Abdominal Fat and Improves Insulin Sensitivity in Older Men With Type 2 Diabetes

OBJECTIVE:--To evaluate the influence of a twice-weekly progressive resistance training (PRT) program, without a concomitant weight loss diet, on abdominal fat and insulin sensitivity in older men with type 2 diabetes. RESEARCH DESIGN AND METHODS--Nine older men (aged 66.6 ± 3.1) with type 2 diabetes participated in a 16-week PRT supervised program (50-80% of the one repetition maximum), for all main muscle groups. Basal glycemia, HbA[subscript 1c], diet, habitual physical activity, body composition, and upper/lower maximal strength were measured. Insulin sensitivity was determined according to Bergman's minimal model procedure and abdominal fat was obtained by computed tomography. The measurements were taken 4 weeks before training (-4), immediately before training (0), and at 8-week intervals (i.e., weeks 8 and 16) during the 16-week training period. RESULTS:--No significant variation was observed in any of the above selected parameters during the 4-week control period. After PRT, both leg and arm maximal strength increased significantly by 17.1 and 18.2%, respectively. Visceral and subcutaneous abdominal fat decreased significantly by 10.3% (from 249.5 ± 97.9 to 225.6 ± 96.6 cm³, P < 0.01) and by 11.2% (from 356.0 ± 127.5 to 308.6 ± 118.8 cm³, P < 0.01), respectively, while no changes were observed in body mass. PRT significantly increased insulin sensitivity by 46.3% (from 2.0 ± 1.2 to 2.8 ± 1.6 · 10⁴ · min⁻¹ · [micro]U⁻¹ · ml⁻¹, P < 0.01), whereas it significantly decreased (-7.1%, P < 0.05) fasting blood glucose (from 146.6 ± 28.3 to 135.0 ± 29.3 mg/dl). Finally, a 15.5% increase in energy intake (from 2,287.1 ± 354.7 to 2,619.0 ± 472.1 kcal/day, P < 0.05) was observed. CONCLUSIONS:--Two sessions per week of PRT, without a concomitant weight loss diet, significantly improves insulin sensitivity and fasting glycemia and decreases abdominal fat in older men with type 2 diabetes.