Int J Sports Med 2005; 26(10): 815-821
DOI: 10.1055/s-2005-837449
Physiology & Biochemistry

© Georg Thieme Verlag KG Stuttgart · New York

Endurance Training: Volume-Dependent Adaptational Changes in Myosin

T. Seene1 , K. Alev1 , P. Kaasik1 , A. Pehme1 , A.-M. Parring2
  • 1Department of Functional Morphology, University of Tartu, Estonia
  • 2Department of Mathematical Statistics, University of Tartu, Estonia
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Publication History

Accepted after revision: September 30, 2004

Publication Date:
15 March 2005 (online)

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Abstract

The purpose of this study was to find the effect of different endurance training volumes on the composition and turnover of myosin. Sixteen-week-old male rats of the Wistar strain were divided into three different volume-based training groups. Changes in myosin heavy chain (MyHC), myosin light chain (MyLC) isoforms' composition, their synthesis rate, as well as myosin binding C-protein synthesis rate, and muscle protein degradation rate were measured. In slow-twitch (ST) soleus (Sol) muscle MyHC I isoform relative content increased and MyHC IIa isoform decreased during excessive increase in the volume of endurance training (ET). In plantaris (Pla) muscle excessive increase in ET volume decreased MyHC I and IIb isoforms, and increased MyHC IIa and IId relative content. In extensor digitorum longus (EDL) muscle the relative content of MyHC IId isoform increased during ET, but excessive increase in training volume decreased it. In Pla muscle the relative content of MyLC 1slow isoform decreased during ET, but excessive increase in ET volume decreased the relative content of MyLC 3fast isoform in both fast-twitch (FT) muscles. Decrease in MyHC and myosin binding C-protein synthesis rate in Pla muscle had significant correlation with ET volume (r = - 0.537, p < 0.05 and r = - 0.727, p < 0.001 subsequently). MyHC I and IIb isoforms and MyLC 3fast isoform in Pla muscle and MyHC IIb, IId and MyLC 3fast isoforms in EDL muscle are the most sensitive to the increase in ET volume. Excessive increase in ET volume leads to a decrease in physical working capacity. The degradation of muscle protein increased during ET in all groups.

References

T. Seene

Department of Functional Morphology, Institute of Exercise Biology, University of Tartu

Ülikooli Str. 18

50090 Tartu

Estonia

Phone: + 3727375364

Fax: + 37 27 37 53 62

Email: teet.seene@ut.ee