Strength training improves muscle aerobic capacity and glucose tolerance in elderly.

The primary aim of this study was to investigate the effect of short-term resistance training (RET) on mitochondrial protein content and glucose tolerance in elderly. Elderly women and men (age 71 +/- 1, mean +/- SEM) were assigned to a group performing 8 weeks of resistance training (RET, n=12) or no training (CON, n=9). The RET group increased in (i) knee extensor strength (concentric +11 +/- 3%, eccentric+8 +/- 3% and static +12 +/- 3%), (ii) initial (0-30ms) rate of force development (+52 +/- 26%) and (iii) contents of proteins related to signaling of muscle protein synthesis (Akt+69 +/- 20 and mammalian target of rapamycin +69 +/- 32%). Muscle fiber type composition changed to a more oxidative profile in RET with increased amount of type IIa fibers (+26.9 +/- 6.8%) and a trend for decreased amount of type IIx fibers (-16.4 +/- 18.2%, P=0.068). Mitochondrial proteins (OXPHOS complex II, IV, and citrate synthase) increased in RET by +30 +/- 11%, +99 +/- 31% and +29 +/- 8%, respectively. RET resulted in improved oral glucose tolerance measured as reduced area under curve for glucose (-21 +/- 26%) and reduced plasma glucose 2h post-glucose intake (-14 +/- 5%). In CON parameters were unchanged or impaired. In conclusion, short-term resistance training in elderly not only improves muscular strength, but results in robust increases in several parameters related to muscle aerobic capacity.