Int J Sports Med 2003; 24(4): 264-270
DOI: 10.1055/s-2003-39509
Physiology & Biochemistry
© Georg Thieme Verlag Stuttgart · New York

Effects of High Intensity Resistance and Low Intensity Endurance Training on Myosin Heavy Chain Isoform Expression in Highly Trained Rowers

Y.  Liu1 , W.  Lormes1 , S.  Reißnecker1 , J. M.  Steinacker1
  • 1Department of Sports and Rehabilitation Medicine, University of Ulm, Ulm, Germany
Further Information

Publication History

Accepted after revision: November 26, 2002

Publication Date:
04 June 2003 (online)

Abstract

An important mechanism of muscle adaptation to exercise is the alteration of myosin heavy chain (MHC) isoform expression. This study investigated the effect of a high intensity resistance training (HIRT) and a low intensity endurance rowing (LIER) on MHC isoform expression in highly trained human muscle. Six well-trained male rowers underwent a training program consisting of a 3-week HIRT and a 3-week LIER, each followed by one-week of recovery. Muscle samples were taken from vastus lateralis before and at the end of each training and recovery phase. MHC isoform was analyzed by SDS-PAGE using silver stain and MHC isoform mRNA by RT-PCR. The maximum oxygen uptake and power output did not change after the training. MHC isoform composition did not change over HIRT or LIER, and there was a decrease in MHC I with concomitant increase in MHC IIa after recovery following HIRT. HIRT led to mRNA upregulation of MHC Iα, Iβ and IIx (127 %, 148 % and 117 %, respectively, p < 0.05), but not MHC I protein (60 % vs 62 %, NS), and LIER led merely to MHC Iβ mRNA upregulation (131 %, p < 0.05). Thus, different responses of MHC isoform expression to HIRT and LIER occurred in the highly trained muscle, and a “ceiling effect” in terms of MHC I expression could be observed. The upregulation of MHC Iα mRNA in human skeletal muscle documented in this study may encourage further observations in this field.

References

Dr. med. Y. Liu

Abt. Sport- und Rehabilitationsmedizin · Universitätsklinikum Ulm

Steinhövelstr. 9 · 89070 Ulm ·

Phone: +49 731 50026966

Fax: +49 731 50026686

Email: yuefei.liu@medizin.uni-ulm.de