Summary
The glycogen content was measured in biopsy samples of human vastus lateralis muscle during prolonged isometric contraction with low force generation. In the first experiment 15% of the maximum voluntary contraction force (MVC) was held for 10 min. Glycogen utilization was 68.1 mmol glucosyl units · kg−1 dry muscle (d.m.). The study was continued by intermittent contractions of 50 s duration and 10 s rest repeated for 50 min. This resulted in a total glycogen utilization of 167.5 mmol glucosyl units · kg−1 d.m. The study was repeated with a force set to 7.5% MVC starting with 20 min continuous contraction followed by the same intermittent contractions for a further 100 min. The glycogen decrease was 15 mmol after the continuous contraction and totally 50 mmol after 2 h with the lower force. Thus the glycogen degradation rate even at low contraction force was related to the force level, being 6 times higher when the force was increased from 7.5 to 15% MVC. With prolonged isometric work periods at work loads corresponding to 15% MVC or higher depletion of the glycogen store can limit work performance capacity.
Similar content being viewed by others
References
Bergström J (1975) Percutaneous needle biopsy of skeletal muscle in physiological and clinical research. Scand J Clin Lab Invest 35:609–619
Harris RC, Hultman E, Nordesjö L-O (1974) Glcyogen, glycolytic intermediates and high energy phosphates determined in biopsy samples of musculus quadriceps femoris of man at rest. Methods and variances of values. Scand J Clin Lab Invest 33:109–120
Hultman E, Sjöholm H (1986) Biochemical causes of fatigue. In: Jones NL, McCartney N, McComas AJ (eds). Human muscle power. Human Kinetic Publ Inc Champaign, IL, pp 215–238
Hultman E, Spriet LL, Söderlund K (1987) Energy metabolism and fatigue in working muscles. In: Macleod D, Maughan R, Nimmo M, Reilly R, Williams C (eds). Exercise — benefits, limits and adaptations. E & FN Spon, London, New York, pp 63–84
Kilbom Å, Persson J (1982) Leg blood flow during static exercise. Eur J Appl Physiol 48:367–377
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hultman, E., Söderlund, K. Glycogen degradation during isometric exercise at low contraction force. Europ. J. Appl. Physiol. 58, 225–227 (1988). https://doi.org/10.1007/BF00417253
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00417253