Co-existence of myosin heavy chain I and IIa isoforms in human skeletal muscle fibres with endurance training

Pflugers Arch. 1990 Jun;416(4):470-2. doi: 10.1007/BF00370757.


The myosin heavy chain (MHC) composition of single fibres from m. vastus lateralis was analysed by one-dimensional electrophoresis and immunoblotting in three groups of young men with distinct difference in physical activity patterns. No major co-existence of MHC isoforms was found in the group with some daily physical activity. In the very sedentary group, however, 19 +/- 5% (P less than 0.05) of the fibres exhibited coexistence of MHC type IIa and IIb. Further, in the endurance trained group co-existence of MHC type I and IIa was manifested in 36 +/- 4% (P less than 0.05) of the fibres. Disuse and extreme usage of muscle both give rise to an elevation in co-expression of MHC isoforms in single muscle fibres but of markedly different combination of isoforms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Electrophoresis
  • Humans
  • Immunohistochemistry
  • Muscles / cytology
  • Muscles / metabolism*
  • Muscles / physiology
  • Myosins / analysis
  • Myosins / metabolism*
  • Myosins / physiology
  • Physical Endurance / physiology*


  • Myosins