The effects of duration of training on VO2(max) and citrate synthase activity in muscle during detraining

J. L. Azevedo, H. L. Auleb, S. J. Evans, W. T. Willis

Research output: Contribution to journalArticlepeer-review


Two groups of rats were endurance trained by treadmill running for an hour a day five days a week for either 5 (n=12) or 11 (n=14) weeks. Maximal oxygen consumption (V̇O2max) was determined at 1, 9, and 19 days, and muscle samples were taken at 3, 11, and 21 days after cessation of training. There were no differences in V̇O2max between groups nor were there any changes in V̇O2max within any of the groups during detraining. Citrate synthase (CS) activity in deep vastus lateralis muscle was increased 30% (P<0.01) to 39.9 and 40.9 micromol/min gram wet muscle in the 5 and 11 week trained animals, respectively, compared to the control group (29.8 micromol/min gram wet muscle) 3 days post-training. Eleven days after the cessation of training CS activity in both groups descreased to 12% above control levels. At 21 days post-training CS activity of both groups returned to control levels. Therefore, it was concluded: 1) elevated muscle oxidative capacity from endurance training (as indicated by CS activity) is maintained only by constant stimulus input; 2) the duration of training has no effect on the rate of decrease of muscle oxidative capacity during detraining; and 3) V̇O2max and muscle oxidative capacity decline at different rates during detraining.

Original languageEnglish (US)
Pages (from-to)No. 3525
JournalFederation Proceedings
Issue number4
StatePublished - 1985
Externally publishedYes

ASJC Scopus subject areas

  • General Medicine


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