Lower muscle strength gains in older men with type 2 diabetes after resistance training

Abstract

This investigation compared the effects of a twice-weekly whole-body supervised progressive resistance training program in older men with type 2 diabetes with those in healthy older men. Twenty sedentary older men participated in a 16-week progressive resistance training study. They were assigned either to a control group (n=11) or to a type 2 diabetes group (n=9). Lower as well as upper body maximal strength (one repetition maximum) and power testing and blood draws to determine basal hormone concentrations (total as well as free testosterone and cortisol) were conducted 4 weeks before training and then at Weeks 0 and 16. The training program consisted of intensities ranging from 50% to 80% of one repetition maximum, 5 to 15 repetitions per set, and three to four sets of each exercise. Baseline maximal muscle strength was not significantly different between groups. After training, significant differences were observed in the magnitude of increments in maximal arm strength and leg strength between the control and type 2 diabetes groups (36.7%+/-12.9% vs. 24.2%+/-4.1%, P=.04, and 35.6%+/-12.2% vs. 17.0%+/-3.8%, P<.01, respectively), whereas no significant difference was observed between groups in the power output increments of the arm and leg extensor muscles (22.5%+/-21.3% vs. 23.8%+/-18.3% and 34.2%+/-32.0% vs. 33.0%+/-21.2%, respectively). At baseline, significant differences were observed in the concentrations of total testosterone and cortisol between the control subjects and the patients with type 2 diabetes (20.3+/-6.0 vs. 10.6+/-2.9 nmol/l, P<.001, and 546.5+/-114.7 vs. 343.2+/-98.4 nmol/l, P<.001, respectively). However, no systematic change was observed during the 16-week strength training period in the basal concentrations of serum total as well as free testosterone and cortisol in both groups. In contrast, statistically significant correlations were observed in a combined group of healthy older men and older men with type 2 diabetes (H+D group) between the mean levels of individual serum total testosterone and cortisol (averaged for the entire training period) and the individual changes in maximal leg strength and arm strength (r=0.85-0.51 and 0.63-0.70, respectively, P<.05). In summary, it would appear that older subjects with type 2 diabetes are equally trainable for muscle power output but not for maximal strength as their healthy counterparts.