Journal of Applied Physiology, Vol 78, Issue 1 138-145, Copyright © 1995 by American Physiological Society

ARTICLES

Adaptations in muscle metabolism to prolonged voluntary exercise and training

H. J. Green, S. Jones, M. Ball-Burnett, B. Farrance and D. Ranney
Department of Kinesiology, University of Waterloo, Ontario, Canada.

In previous research we established using a short-term (5-7 days) training model that increases in muscle oxidative potential are not a prerequisite for the characteristic energy metabolic adaptations (lower lactate, glycogen depletion, and phosphocreatine hydrolysis) observed during prolonged exercise. To investigate whether increased muscle aerobic potential further potentiates the metabolic adaptive response, seven healthy male volunteers [maximal O2 uptake (VO2max) = 45.1 +/- 1.1 (SE) ml.kg-1.min-1] engaged in an 8-wk training program consisting of 2 h of cycle exercise at 62% of pretraining VO2max 5-6 times/wk. Analysis of tissue samples obtained from the vastus lateralis after 60 min of exercise revealed that by 4 wk of training muscle lactate concentration, phosphocreatine hydrolysis, and glycogen depletion were depressed (all P < 0.05). Further training for 4 wk had no additional effect (P < 0.05). The ratio of fructose 6-phosphate to fructose 1,6-phosphate, an index of phosphofructokinase activity, was not altered with training. Muscle oxidative potential as estimated from the maximal activity of succinic dehydrogenase increased by 31% by 4 wk of training (P < 0.05) before plateauing during the final 4 wk of training. The increase in VO2max of 15.6% (P < 0.05) noted with training was also primarily expressed during the initial 4 wk. O2 uptake during submaximal exercise was unchanged. Because the metabolic response was similar in magnitude to that previously observed with short-term training, we conclude that, at least for the conditions of this study, the development of increased muscle aerobic potential is of minimal consequence on the magnitude of the energy metabolic adaptations examined.

This article has been cited by other articles:

				J. J. Dube, F. Amati, M. Stefanovic-Racic, F. G. S. Toledo, S. E. Sauers, and B. H. Goodpaster Exercise-induced alterations in intramyocellular lipids and insulin resistance: the athlete's paradox revisited Am J Physiol Endocrinol Metab, May 1, 2008; 294(5): E882 - E888. [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]

				P. J. LeBlanc, K. R. Howarth, M. J. Gibala, and G. J. F. Heigenhauser Effects of 7 wk of endurance training on human skeletal muscle metabolism during submaximal exercise J Appl Physiol, December 1, 2004; 97(6): 2148 - 2153. [Abstract] [Full Text] [PDF]

				J. Baldwin, R. J. Snow, M. J. Gibala, A. Garnham, K. Howarth, and M. A. Febbraio Glycogen availability does not affect the TCA cycle or TAN pools during prolonged, fatiguing exercise J Appl Physiol, June 1, 2003; 94(6): 2181 - 2187. [Abstract] [Full Text] [PDF]

				N. A. Johnson, S. R. Stannard, K. Mehalski, M. I. Trenell, T. Sachinwalla, C. H. Thompson, and M. W. Thompson Intramyocellular triacylglycerol in prolonged cycling with high- and low-carbohydrate availability J Appl Physiol, April 1, 2003; 94(4): 1365 - 1372. [Abstract] [Full Text] [PDF]

				S. Levine, C. Gregory, T. Nguyen, J. Shrager, L. Kaiser, N. Rubinstein, and G. Dudley Bioenergetic adaptation of individual human diaphragmatic myofibers to severe COPD J Appl Physiol, March 1, 2002; 92(3): 1205 - 1213. [Abstract] [Full Text] [PDF]

				A. R. Harmer, M. J. McKenna, J. R. Sutton, R. J. Snow, P. A. Ruell, J. Booth, M. W. Thompson, N. A. Mackay, C. G. Stathis, R. M. Crameri, et al. Skeletal muscle metabolic and ionic adaptations during intense exercise following sprint training in humans J Appl Physiol, November 1, 2000; 89(5): 1793 - 1803. [Abstract] [Full Text] [PDF]

				H. Green, R. Tupling, B. Roy, D. O'Toole, M. Burnett, and S. Grant Adaptations in skeletal muscle exercise metabolism to a sustained session of heavy intermittent exercise Am J Physiol Endocrinol Metab, January 1, 2000; 278(1): E118 - E126. [Abstract] [Full Text] [PDF]

				M. A. Febbraio and J. Dancey Skeletal muscle energy metabolism during prolonged, fatiguing exercise J Appl Physiol, December 1, 1999; 87(6): 2341 - 2347. [Abstract] [Full Text] [PDF]

				G. McConell, R. J. Snow, J. Proietto, and M. Hargreaves Muscle metabolism during prolonged exercise in humans: influence of carbohydrate availability J Appl Physiol, September 1, 1999; 87(3): 1083 - 1086. [Abstract] [Full Text] [PDF]

				H. Green, S. Grant, E. Bombardier, and D. Ranney Initial aerobic power does not alter muscle metabolic adaptations to short-term training Am J Physiol Endocrinol Metab, July 1, 1999; 277(1): E39 - E48. [Abstract] [Full Text] [PDF]

				J. Baldwin, R. J. Snow, M. F. Carey, and M. A. Febbraio Muscle IMP accumulation during fatiguing submaximal exercise in endurance trained and untrained men Am J Physiol Regulatory Integrative Comp Physiol, July 1, 1999; 277(1): R295 - R300. [Abstract] [Full Text] [PDF]

				C. Goreham, H. J. Green, M. Ball-Burnett, and D. Ranney High-resistance training and muscle metabolism during prolonged exercise Am J Physiol Endocrinol Metab, March 1, 1999; 276(3): E489 - E496. [Abstract] [Full Text] [PDF]

				E. C. Starritt, D. Angus, and M. Hargreaves Effect of short-term training on mitochondrial ATP production rate in human skeletal muscle J Appl Physiol, February 1, 1999; 86(2): 450 - 454. [Abstract] [Full Text] [PDF]

				E. A. Richter, P. Jensen, B. Kiens, and S. Kristiansen Sarcolemmal glucose transport and GLUT-4 translocation during exercise are diminished by endurance training Am J Physiol Endocrinol Metab, January 1, 1998; 274(1): E89 - E95. [Abstract] [Full Text] [PDF]