| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
To investigate the
hypothesis that training-induced increases in muscle mitochondrial
potential are not obligatory to metabolic adaptations observed during
submaximal exercise, regardless of peak aerobic power
(
O2 peak)
of the subjects, a short-term training study was utilized. Two groups
of untrained male subjects (n = 7/group), one with a high (HI) and the other with a low (LO)
O2 peak (means ± SE; 51.4 ± 0.90 vs. 41.0 ± 1.3 ml · kg
1 · min1;P < 0.05), cycled for 2 h/day at 66-69% of
O2 peak for 6 days. Muscle tissue was extracted from vastus lateralis at 0, 3, and 30 min
of standardized cycle exercise before training (0 days) and after 3 and
6 days of training and analyzed for metabolic and enzymatic changes.
During exercise after 3 days of training in the combined HI + LO group,
higher (P < 0.05) concentrations (mmol/kg dry wt) of phosphocreatine (40.5 ± 3.4 vs. 52.2 ± 4.2) and lower (P < 0.05) concentrations
of Pi (61.5 ± 4.4 vs. 53.3 ± 4.4), inosine monophosphate (0.520 ± 0.19 vs. 0.151 ± 0.05), and lactate (37.9 ± 5.5 vs. 22.8 ± 4.8) were
observed. These changes were also accompanied by reduced levels of
calculated free ADP, AMP, and Pi.
All adaptations were fully expressed by 3 min of exercise and by 3 days
of training and were independent of initial O2 peak levels.
Moreover, maximal activity of citrate synthase, a measure of
mitochondrial capacity, was only increased with 6 days of training
(5.71 ± 0.29 vs. 7.18 ± 0.37 mol · kg
protein1 · h1;
P < 0.05). These results demonstrate
that metabolic adaptations to prolonged exercise occur within the first
3 days of training and during the non-steady-state period. Moreover,
neither time course nor magnitude of metabolic adaptations appears to
depend on increases in mitochondrial potential or on initial aerobic power.
enzymatic, adaptation, cycling, oxidative phosphorylation
This article has been cited by other articles:
|
|
 |
|
  H. J. Green, E. B. Bombardier, T. A. Duhamel, G. P. Holloway, A. R. Tupling, and J. Ouyang Acute responses in muscle mitochondrial and cytosolic enzyme activities during heavy intermittent exercise J Appl Physiol, April 1, 2008; 104(4): 931 - 937. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. A. Duhamel, R. D. Stewart, A. R. Tupling, J. Ouyang, and H. J. Green Muscle sarcoplasmic reticulum calcium regulation in humans during consecutive days of exercise and recovery J Appl Physiol, October 1, 2007; 103(4): 1212 - 1220. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Talanian, S. D. R. Galloway, G. J. F. Heigenhauser, A. Bonen, and L. L. Spriet Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women J Appl Physiol, April 1, 2007; 102(4): 1439 - 1447. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. A. Duhamel, H. J. Green, J. G. Perco, and J. Ouyang Comparative effects of a low-carbohydrate diet and exercise plus a low-carbohydrate diet on muscle sarcoplasmic reticulum responses in males Am J Physiol Cell Physiol, October 1, 2006; 291(4): C607 - C617. [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]
|
|
|
|
|
|
T. A. Duhamel, H. J. Green, J. G. Perco, and J. Ouyang Effects of prior exercise and a low-carbohydrate diet on muscle sarcoplasmic reticulum function during cycling in women J Appl Physiol, September 1, 2006; 101(3): 695 - 706. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. D. Sandiford, H. J. Green, T. A. Duhamel, J. D. Schertzer, J. D. Perco, and J. Ouyang Muscle Na-K-pump and fatigue responses to progressive exercise in normoxia and hypoxia Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2005; 289(2): R441 - R449. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. A. Burgomaster, S. C. Hughes, G. J. F. Heigenhauser, S. N. Bradwell, and M. J. Gibala Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans J Appl Physiol, June 1, 2005; 98(6): 1985 - 1990. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. J. Green, D. J. Barr, J. R. Fowles, S. D. Sandiford, and J. Ouyang Malleability of human skeletal muscle Na+-K+-ATPase pump with short-term training J Appl Physiol, July 1, 2004; 97(1): 143 - 148. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. A. Duhamel, H. J. Green, J. G. Perco, S. D. Sandiford, and J. Ouyang Human muscle sarcoplasmic reticulum function during submaximal exercise in normoxia and hypoxia J Appl Physiol, July 1, 2004; 97(1): 180 - 187. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. D. Dawson, K. R. Howarth, M. A. Tarnopolsky, N. D. Wong, and M. J. Gibala Short-term training attenuates muscle TCA cycle expansion during exercise in women J Appl Physiol, September 1, 2003; 95(3): 999 - 1004. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. R. Tupling, H. J. Green, B. D. Roy, S. Grant, and J. Ouyang Paradoxical effects of prior activity on human sarcoplasmic reticulum Ca2+-ATPase response to exercise J Appl Physiol, July 1, 2003; 95(1): 138 - 144. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. W. E. Rush and L. L. Spriet Skeletal muscle glycogen phosphorylase a kinetics: effects of adenine nucleotides and caffeine J Appl Physiol, November 1, 2001; 91(5): 2071 - 2078. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Green, B. Roy, S. Grant, C. Otto, A. Pipe, D. McKenzie, and M. Johnson Human skeletal muscle exercise metabolism following an expedition to Mount Denali Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2000; 279(5): R1872 - R1879. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
