Strength training in older women: early and late changes in whole muscle and single cells.
In order to examine the relative contribution of neural- and muscle-based adaptation to strength training, we studied early (2 weeks) and later (12 weeks) effects of strength training on muscle size and strength and type I single-fiber size and contractility in 14 elderly women (aged 68-79 years) and seven young controls. Older subjects were randomized to training (n = 7) or control (n = 7) groups. Strength did not change, but whole muscle size increased significantly after 2 weeks. After 12 weeks, strength, whole muscle size, and specific force all increased. No changes occurred in the control group. In single fibers, no changes in size and contractility were noted after 2 weeks, but specific force was higher in the training group after 12 weeks. Early adaptations to strength training in elderly women cannot be attributed to changes at the cellular level and therefore occur primarily in the central nervous system. Later, cellular adaptations in specific force track closely whole muscle changes.
Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA. frontera.walter@mgh.harvard.edu
Walter R
WR
Frontera
Virginia A
VA
Hughes
Lisa S
LS
Krivickas
Sang-Kyu
SK
Kim
Mona
M
Foldvari
Ronenn
R
Roubenoff
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D032342:Muscle Cells / Q000166:cytology / Q000502:physiology*; D018482:Muscle, Skeletal / Q000166:cytology / Q000502:physiology*; D012044:Regression Analysis; D013997:Time Factors