|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Ball State University
* To whom correspondence should be addressed. E-mail: strappe{at}bsu.edu.
The purpose of this study was to investigate potential differences in single fiber contractile physiology of fibers with the same myosin heavy chain isoform (MHC I and MHC IIa) originating from different muscles. Vastus lateralis (VL) and soleus biopsies were obtained from 27 recreationally active females (31 ± 1 y, 59 ± 1 kg). A total of 942 single fibers (MHC I = 562; MHC IIa = 301) were isolated and examined for diameter, peak tension (Po), shortening velocity (Vo), and power. The soleus had larger (P<0.05) fibers (MHC I +18%; MHC IIa +19%), higher MHC I Vo (+13%) and higher MHC I Po (+18%) compared to fibers from the VL. In contrast, fibers from the VL had higher (P<0.05) specific tension (MHC I +18%; MHC IIa +20%), and MHC I normalized power (+25%) compared to the soleus. There was a trend for MHC IIa soleus fibers to have higher Vo [MHC IIa +13% (P=0.058)], whereas VL MHC IIa fibers showed a trend for higher normalized power compared to soleus fibers [MHC IIa +33% (P=0.079)]. No differences in absolute power were detected between muscles. These data highlight muscle specific differences in single fiber contractile function that should serve as a scientific basis for consideration when extending observations of skeletal muscle tissue from one muscle of interest to other muscles of origin. This is important when examining skeletal muscle adaptation to physical states such as aging, unloading, and training.
This article has been cited by other articles:
![]() |
M. P. Harber, J. D. Crane, J. M. Dickinson, B. Jemiolo, U. Raue, T. A. Trappe, and S. W. Trappe Protein synthesis and the expression of growth-related genes are altered by running in human vastus lateralis and soleus muscles Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2009; 296(3): R708 - R714. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |