The authors investigated the effects of low-intensity resistance training on muscle size and strength in older men and women. Thirty-five participants (age 59–76 yr) were randomly assigned to 2 groups and performed low-intensity (50% of 1-repetition maximum) knee-extension and -flexion exercises with either slow movement and tonic force generation (LST; 3-s eccentric, 3-s concentric, and 1-s isometric actions with no rest between repetitions) or normal speed (LN; 1-s concentric and 1-s eccentric actions with 1-s rests between repetitions) twice a week for 12 wk (2-wk preparation and 10-wk intervention). The LST significantly increased thigh-muscle thickness, as well as isometric knee-extension and -flexion strength. The LN significantly improved strength, but its hypertrophic effect was limited. These results indicate that even for older individuals, the LST can be an effective method for gaining muscle mass and strength.
Watanabe and Ishii are with the Dept. of Life Sciences, University of Tokyo, Tokyo, Japan. Tanimoto is with the Dept. of Biomechanical and Human Factors Engineering, Kinki University, Wakayama, Japan. Ohgane is with the Dept. of Functioning Activation, National Center for Geriatrics and Gerontology. Sanada is with the College of Sport and Health Science, Ritsumeikan University, Shiga, Japan. Miyachi is with the Div. of Health Promotion and Exercise, National Institutes of Health and Nutrition. At the time of the research, Tanimoto was with the Div. of Health Promotion and Exercise, National Institutes of Health and Nutrition, and Sanada was with the Consolidated Research Inst. for Advanced Science and Medical Care, Waseda University.