Exercise induced increases in muscle fiber number

  • William J. Gonyea
  • Digby G. Sale
  • Francine B. Gonyea
  • Alan Mikesky


The effect of weight-lifting, which induced muscular enlargement, on fiber number was tested in the flexor carpi radialis muscle by operantly conditioning 6 cats to flex their right wrist against increasing resistance for an average of 101 weeks. The left was used as a control. At the end of training, the cats were performing “one-arm“ lifts with an average of 57% of their body weight. There was an 11% greater muscle weight (P<0.01) and 9% (P<0.02) more fibers in the exercised muscles from the right limb than in the left. This study using a different method, supports our earlier observations that prolonged weight-lifting exercise significantly increases the total number of muscle fibers.

Key words

Weight-lifting exercise Cat Flexor carpi radialis muscle Nitric acid digestion 


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Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • William J. Gonyea
    • 1
  • Digby G. Sale
    • 1
  • Francine B. Gonyea
    • 1
  • Alan Mikesky
    • 1
  1. 1.Department of Cell Biology and AnatomyUniversity of Texas Health Science Center at DallasDallas

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