Pflügers Archiv

, Volume 344, Issue 1, pp 1–12

Glycogen depletion patterns in human skeletal muscle fibers during prolonged work

  • P. D. Gollnick
  • R. B. Armstrong
  • C. W. SaubertIV
  • W. L. Sembrowich
  • R. E. Shepherd
  • B. Saltin
Article

DOI: 10.1007/BF00587437

Cite this article as:
Gollnick, P.D., Armstrong, R.B., Saubert, C.W. et al. Pflugers Arch. (1973) 344: 1. doi:10.1007/BF00587437

Summary

The glycogen depletion pattern in human muscle fibers was followed throughout the course of prolonged exercise at a work load requiring 67% of the subjects' maximal aerobic power. Biopsy samples were taken from the vastus lateralis muscle at rest and after 20, 60, 120, and 180 (or when unable to continue at the prescribed load) min of exercise. Muscle fibers were identified as fast twitch (FT) or slow twitch (ST) on the basis of myofibrillar ATPase activity. The glycogen content of muscle samples was determined biochemically. At the end of the exercise total muscle glycogen content was very low. Glycogen was also estimated in the fibers with the PAS stain. ST fibers were the first to become depleted of their glycogen but as the exercise progressed, the FT fibers were also depleted. These data may suggest a preferential utilization of ST fibers during prolonged, intense exercise, with a secondary recruitment of FT occuring as the ST fibers became depleted of their glycogen stores.

Key words

Slow Muscle Fibers Fast Muscle Fibers Plasma FFA Blood Lactate Metabolism during Exercise Fiber Recruitment Fiber Types 

Copyright information

© Springer-Verlag 1973

Authors and Affiliations

  • P. D. Gollnick
    • 1
  • R. B. Armstrong
    • 1
  • C. W. SaubertIV
    • 1
  • W. L. Sembrowich
    • 1
  • R. E. Shepherd
    • 1
  • B. Saltin
    • 1
  1. 1.Department of Physical Education for MenWashington State UniversityPullmanUSA
  2. 2.Department of PhysiologyGymnastik-och idrottshögskolanStockholmSweden