| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Exercise Metabolism Group, School of Medical Sciences, RMIT University, Melbourne, Victoria, Australia
2 St. Vincent's Institute of Medical Research and Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
3 Muscle, Ions and Exercise Group, School of Human Movement, Recreation and Performance, Centre for Rehabilitation, Exercise and Sports Science, Victoria University of Technology, Melbourne, Victoria, Australia
* To whom correspondence should be addressed. E-mail: john.hawley{at}rmit.edu.au.
The AMPK cascade has been linked to many of the acute effects of exercise on
skeletal muscle substrate metabolism, as well as some of the chronic training-induced
adaptations. We determined the effect of 3 wk of intensified training (7 sessions of 8 x
5 min @ 85% of VO2peak) in skeletal muscle from well-trained athletes on AMPK
responsiveness to exercise. Rates of whole-body substrate oxidation were determined
during a 90 min steady-state ride pre- and post-training. Muscle metabolites and
AMPK signalling were determined from biopsies taken at rest and immediately after
exercise during the 1st and 7th intensified training session, performed at the same
(absolute) pre-training workrate. Training decreased rates of whole-body CHO
oxidation (P<0.05) and increased rates of fat oxidation (P<0.05) during SS. Resting
muscle glycogen and its utilization during intense exercise was unaffected by training.
However training induced a two-fold decrease in muscle [lactate] (P<0.05) and
resulted in tighter metabolic regulation (i.e. attenuation of the decrease in the
PCr/(PCr + Cr) ratio and of the increase in [AMP free]/ATP). The resting activities of
AMPK
-1 and -2 were similar after training, with the magnitude of the rise in
response to exercise similar before and after training. AMPK phosphorylation at
Thr172 on both the -1 and -2 subunits increased in response to exercise with the
magnitude of this rise being similar post training. ACC-
phosphorylation was similar
at rest and, despite training-induced increases in whole-body rates of fat oxidation, did
not increase after intensified training. Our results indicate that in well-trained
individuals, short-term intensified training improves metabolic control but does not
blunt AMPK signalling in response to intense exercise.
This article has been cited by other articles:
|
|
 |
|
  W. K. Yeo, C. D. Paton, A. P. Garnham, L. M. Burke, A. L. Carey, and J. A. Hawley Skeletal muscle adaptation and performance responses to once a day versus twice every second day endurance training regimens J Appl Physiol, November 1, 2008; 105(5): 1462 - 1470. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. K. Yeo, S. J. Lessard, Z.-P. Chen, A. P. Garnham, L. M. Burke, D. A. Rivas, B. E. Kemp, and J. A. Hawley Fat adaptation followed by carbohydrate restoration increases AMPK activity in skeletal muscle from trained humans J Appl Physiol, November 1, 2008; 105(5): 1519 - 1526. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Pedersen, S. J. Lessard, V. G. Coffey, E. G. Churchley, A. M. Wootton, T. Ng, M. J. Watt, and J. A. Hawley High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine J Appl Physiol, July 1, 2008; 105(1): 7 - 13. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Vissing, S. L. McGee, C. Roepstorff, P. Schjerling, M. Hargreaves, and B. Kiens Effect of sex differences on human MEF2 regulation during endurance exercise Am J Physiol Endocrinol Metab, February 1, 2008; 294(2): E408 - E415. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Aughey, K. T. Murphy, S. A. Clark, A. P. Garnham, R. J. Snow, D. Cameron-Smith, J. A. Hawley, and M. J. McKenna Muscle Na+-K+-ATPase activity and isoform adaptations to intense interval exercise and training in well-trained athletes J Appl Physiol, July 1, 2007; 103(1): 39 - 47. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. G. R. Perry, J. L. Talanian, G. J. F. Heigenhauser, and L. L. Spriet The effects of training in hyperoxia vs. normoxia on skeletal muscle enzyme activities and exercise performance J Appl Physiol, March 1, 2007; 102(3): 1022 - 1027. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. J. Gibala, J. P. Little, M. van Essen, G. P. Wilkin, K. A. Burgomaster, A. Safdar, S. Raha, and M. A. Tarnopolsky Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance J. Physiol., September 15, 2006; 575(3): 901 - 911. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. E. Kuhl, N. B. Ruderman, N. Musi, L. J. Goodyear, M. E. Patti, S. Crunkhorn, D. Dronamraju, A. Thorell, J. Nygren, O. Ljungkvist, et al. Exercise training decreases the concentration of malonyl-CoA and increases the expression and activity of malonyl-CoA decarboxylase in human muscle Am J Physiol Endocrinol Metab, June 1, 2006; 290(6): E1296 - E1303. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Toyoda, S. Tanaka, K. Ebihara, H. Masuzaki, K. Hosoda, K. Sato, T. Fushiki, K. Nakao, and T. Hayashi Low-intensity contraction activates the {alpha}1-isoform of 5'-AMP-activated protein kinase in rat skeletal muscle Am J Physiol Endocrinol Metab, March 1, 2006; 290(3): E583 - E590. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. J. Lessard, Z.-P. Chen, M. J. Watt, M. Hashem, J. J. Reid, M. A. Febbraio, B. E. Kemp, and J. A. Hawley Chronic rosiglitazone treatment restores AMPK{alpha}2 activity in insulin-resistant rat skeletal muscle Am J Physiol Endocrinol Metab, February 1, 2006; 290(2): E251 - E257. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
