| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Journal of Applied Physiology, Vol 80, Issue 3 981-987, Copyright © 1996 by American Physiological Society
ARTICLES |
J. J. Widrick, J. J. Bangart, M. Karhanek and R. H. Fitts
Department of Biology, Marquette University, Milwaukee, Wisconsin 53201, USA.
This study examined the effectiveness of intermittent weight bearing (IWB) as a countermeasure to non-weight-bearing (NWB)-induced alterations in soleus type I fiber force (in mN), tension (Po; force per fiber cross-sectional area in kN/m-2), and maximal unloaded shortening velocity (Vo, in fiber lengths/s). Adult rats were assigned to one of the following groups: normal weight bearing (WB), 14 days of hindlimb NWB (NWB group), and 14 days of hindlimb NWB with IWB treatments (IWB group). The IWB treatment consisted of four 10-min periods of standing WB each day. Single, chemically permeabilized soleus fiber segments were mounted between a force transducer and position motor and were studied at maximal Ca2+ activation, after which type I fiber myosin heavy-chain composition was confirmed by sodium dodecyl sufate-polyacrylamide gel electrophoresis. NWB resulted in a loss in relative soleus mass (-45%), with type I fibers displaying reductions in diameter (-28%) and peak isometric force (-55%) and an increase in Vo (+33%). In addition, NWB induced a 16% reduction in type I fiber Po, a 41% reduction in type I fiber peak elastic modulus [Eo, defined as (delta force/delta length) x (fiber length/fiber cross-sectional area] and a significant increase in the Po/Eo ratio. In contrast to NWB, IWB reduced the loss of relative soleus mass (by 22%) and attenuated alterations in type I fiber diameter (by 36%), peak force (by 29%), and Vo (by 48%) but had no significant effect on Po, Eo, or Po/Eo. These results indicate that a modest restoration of WB activity during 14 days of NWB is sufficient to attenuate type I fiber atrophy and to partially restore type I peak isometric force and Vo to WB levels. However, the NWB-induced reductions in Po and Eo, which we hypothesize to be due to a decline in the number and stiffness of cross bridges, respectively, are considerably less responsive to this countermeasure treatment.
This article has been cited by other articles:
|
|
 |
|
  S. Trappe, A. Creer, K. Minchev, D. Slivka, E. Louis, N. Luden, and T. Trappe Human soleus single muscle fiber function with exercise or nutrition countermeasures during 60 days of bed rest Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R939 - R947. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. E. Dupont-Versteegden, J. D. Fluckey, M. Knox, D. Gaddy, and C. A. Peterson Effect of flywheel-based resistance exercise on processes contributing to muscle atrophy during unloading in adult rats J Appl Physiol, July 1, 2006; 101(1): 202 - 212. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. A. Riley, J. L. W. Bain, J. G. Romatowski, and R. H. Fitts Skeletal muscle fiber atrophy: altered thin filament density changes slow fiber force and shortening velocity Am J Physiol Cell Physiol, February 1, 2005; 288(2): C360 - C365. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Gallegly, N. A. Turesky, B. A. Strotman, C. M. Gurley, C. A. Peterson, and E. E. Dupont-Versteegden Satellite cell regulation of muscle mass is altered at old age J Appl Physiol, September 1, 2004; 97(3): 1082 - 1090. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. E. Hurst and R. H. Fitts Hindlimb unloading-induced muscle atrophy and loss of function: protective effect of isometric exercise J Appl Physiol, October 1, 2003; 95(4): 1405 - 1417. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L.-F. Zhang, B. Sun, X.-S. Cao, C. Liu, Z.-B. Yu, L.-N. Zhang, J.-H. Cheng, Y.-H. Wu, and X.-Y. Wu Effectiveness of intermittent -Gx gravitation in preventing deconditioning due to simulated microgravity J Appl Physiol, July 1, 2003; 95(1): 207 - 218. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Toursel, L. Stevens, H. Granzier, and Y. Mounier Passive tension of rat skeletal soleus muscle fibers: effects of unloading conditions J Appl Physiol, April 1, 2002; 92(4): 1465 - 1472. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Yamashita-Goto, R. Okuyama, M. Honda, K. Kawasaki, K. Fujita, T. Yamada, I. Nonaka, Y. Ohira, and T. Yoshioka Maximal and submaximal forces of slow fibers in human soleus after bed rest J Appl Physiol, July 1, 2001; 91(1): 417 - 424. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Widrick, J. G. Romatowski, K. M. Norenberg, S. T. Knuth, J. L. W. Bain, D. A. Riley, S. W. Trappe, T. A. Trappe, D. L. Costill, and R. H. Fitts Functional properties of slow and fast gastrocnemius muscle fibers after a 17-day spaceflight J Appl Physiol, June 1, 2001; 90(6): 2203 - 2211. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. H. Fitts, D. Desplanches, J. G. Romatowski, and J. J. Widrick Spaceflight effects on single skeletal muscle fiber function in the rhesus monkey Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2000; 279(5): R1546 - R1557. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Michael Relationship of Skeletal Muscle Atrophy to Functional Status: A Systematic Research Review Biol Res Nurs, October 1, 2000; 2(2): 117 - 131. [Abstract] [PDF]
|
|
|
|
|
|
R. H. Fitts, D. R. Riley, and J. J. Widrick Physiology of a Microgravity Environment Invited Review: Microgravity and skeletal muscle J Appl Physiol, August 1, 2000; 89(2): 823 - 839. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. H. Fitts, S. C. Bodine, J. G. Romatowski, and J. J. Widrick Velocity, force, power, and Ca2+ sensitivity of fast and slow monkey skeletal muscle fibers J Appl Physiol, May 1, 1998; 84(5): 1776 - 1787. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Widrick, J. G. Romatowski, J. L. W. Bain, S. W. Trappe, T. A. Trappe, J. L. Thompson, D. L. Costill, D. A. Riley, and R. H. Fitts Effect of 17 days of bed rest on peak isometric force and unloaded shortening velocity of human soleus fibers Am J Physiol Cell Physiol, November 1, 1997; 273(5): C1690 - C1699. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Bangart, J. J. Widrick, and R. H. Fitts Effect of intermittent weight bearing on soleus fiber force-velocity-power and force-pCa relationships J Appl Physiol, June 1, 1997; 82(6): 1905 - 1910. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Widrick and R. H. Fitts Peak force and maximal shortening velocity of soleus fibers after non-weight-bearing and resistance exercise J Appl Physiol, January 1, 1997; 82(1): 189 - 195. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. E. Dupont-Versteegden, M. Knox, C. M. Gurley, J. D. Houle, and C. A. Peterson Maintenance of muscle mass is not dependent on the calcineurin-NFAT pathway Am J Physiol Cell Physiol, June 1, 2002; 282(6): C1387 - C1395. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
