Insulin-like growth factor I in skeletal muscle after weight-lifting exercise in frail elders.

Journal Article (Clinical Trial;Journal Article)

To assess muscle remodeling and functional adaptation to exercise and diet interventions, 26 men and women aged 72-98 yr underwent a vastus lateralis biopsy before and after placebo control condition, and progressive resistance training, multinutrient supplementation, or both. Type II atrophy, Z band, and myofibril damage were present at baseline. Combined weight lifting and nutritional supplementation increased strength by 257 +/- 62% (P = 0.0001) and type II fiber area by 10.1 +/- 9.0% (P = 0.033), with a similar trend for type I fiber area (+12.8 +/- 22.2%). Exercise was associated with a 2. 5-fold increase in neonatal myosin staining (P = 0.0009) and an increase of 491 +/- 137% (P < 0.0001) in IGF-I staining. Ultrastructural damage increased by 141 +/- 59% after exercise training (P = 0.034). Strength increases were largest in those with the greatest increases in myosin, IGF-I, damage, and caloric intake during the trial. Age-related sarcopenia appears largely confined to type II muscle fibers. Frail elders respond robustly to resistance training with musculoskeletal remodeling, and significant increases in muscle area are possible with resistance training in combination with adequate energy intakes.

Full Text

Duke Authors

Cited Authors

  • Singh, MA; Ding, W; Manfredi, TJ; Solares, GS; O'Neill, EF; Clements, KM; Ryan, ND; Kehayias, JJ; Fielding, RA; Evans, WJ

Published Date

  • July 1999

Published In

Volume / Issue

  • 277 / 1

Start / End Page

  • E135 - E143

PubMed ID

  • 10409137

International Standard Serial Number (ISSN)

  • 0002-9513

Digital Object Identifier (DOI)

  • 10.1152/ajpendo.1999.277.1.E135


  • eng

Conference Location

  • United States