| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Physiology & Biophysics, University of California, Irvine, Irvine, California, United States
* To whom correspondence should be addressed. E-mail: kmbaldwi{at}uci.edu.
Previously, we reported that an isometric resistance training program, that was effective in stimulating muscle hypertrophy in ambulatory rats, could not completely prevent muscle atrophy during unloading (JAP 100:433, 2006). These results indicated that preventing muscle atrophy does not appear to be simply a function of providing an anabolic stimulus. The current study was undertaken to determine if resistance training, with increased volume (3s contractions) and incorporating both static and dynamic components, would be effective in preventing unloading induced muscle atrophy. Rats were exposed to 5 days of muscle unloading via tail suspension. During that time one leg received electrically stimulated resistance exercise (RE) that included an isometric, concentric and eccentric phase. The results of this study indicate that this combined mode RE provided an anabolic stimulus sufficient to maintain the mass and myofibil content of the trained but not the contralateral medial gastrocnemius (MG) muscle. Relative to the contralateral MG, the RE stimulus increased the amount of total RNA (indicative of translational capacity) as well as the mRNA for several anabolic / myogenic markers such as: insulin-like growth factor-I, myogenin, myoferlin and procollagen III-alpha-1 and decreased that of myostatin, a negative regulator of muscle size. The combined mode RE protocol also increased the activity of anabolic signaling intermediates such as p70S6 Kinase. These results indicate that a combination of static and dynamic mode RE of sufficient volume provides an effective stimulus to stimulate anabolic/myogenic mechanisms to counter the initial stages of unloading induced muscle atrophy.
This article has been cited by other articles:
|
|
 |
|
  S. M. Phillips, E. I. Glover, and M. J. Rennie Alterations of protein turnover underlying disuse atrophy in human skeletal muscle J Appl Physiol, September 1, 2009; 107(3): 645 - 654. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Farthing, J. R. Krentz, and C. R. A. Magnus Strength training the free limb attenuates strength loss during unilateral immobilization J Appl Physiol, March 1, 2009; 106(3): 830 - 836. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. W. Bodell, E. Kodesh, F. Haddad, F. P. Zaldivar, D. M. Cooper, and G. R. Adams Skeletal muscle growth in young rats is inhibited by chronic exposure to IL-6 but preserved by concurrent voluntary endurance exercise J Appl Physiol, February 1, 2009; 106(2): 443 - 453. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. M. Heinemeier, J. L. Olesen, F. Haddad, P. Schjerling, K. M. Baldwin, and M. Kjaer Effect of unloading followed by reloading on expression of collagen and related growth factors in rat tendon and muscle J Appl Physiol, January 1, 2009; 106(1): 178 - 186. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Rinaldi, F. Haddad, P. W. Bodell, A. X. Qin, W. Jiang, and K. M. Baldwin Intergenic bidirectional promoter and cooperative regulation of the IIx and IIb MHC genes in fast skeletal muscle Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2008; 295(1): R208 - R218. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. D. Kollias and J. C. McDermott Transforming growth factor-{beta} and myostatin signaling in skeletal muscle J Appl Physiol, March 1, 2008; 104(3): 579 - 587. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
