Resistance exercise training increases mixed muscle protein synthesis rate in frail women and men [76 yr old

mixed muscle protein synthesis rate in frail women and men $76 yr old. Am. J. Physiol. 277 (Endocrinol. Metab. 40): E118–E125, 1999.—Muscle atrophy (sarcopenia) in the el-derly is associated with a reduced rate of muscle protein synthesis. The purpose of this study was to determine if weight-lifting exercise increases the rate of muscle protein synthesis in physically frail 76- to 92-yr-old women and men. Eight women and 4 men with mild to moderate physical frailty were enrolled in a 3-mo physical therapy program that was followed by 3 mo of supervised weight-lifting exercise. Supervised weight-lifting exercise was performed 3 days/wk at 65–100 % of initial 1-repetition maximum on five upper and three lower body exercises. Compared with before resistance training, the in vivo incorporation rate of [13C]leucine into vastus lateralis muscle protein was increased after resistance training in women and men (P, 0.01), although it was unchanged in five 82 6 2-yr-old control subjects studied two times in 3 mo. Maximum voluntary knee extensor muscle torque production increased in the supervised resistance exercise group. These findings suggest that muscle contrac-tile protein synthetic pathways in physically frail 76- to 92-yr-old women and men respond and adapt to the increased contractile activity associated with progressive resistance exercise training. sarcopenia; stable isotopes; mass spectrometry; physical activ-ity SARCOPENIA REFERS TO the undesirable loss of muscle mass that accompanies advancing age. It is associated with muscle weakness, increased fatigability, and a loss of independent function, all characteristics of physica