The slow components of phosphocreatine and pulmonary oxygen uptake can be dissociated during heavy exercise according to training status

Autor: Layec, G., Bringard, A., Yashiro, K., Le Fur, Y., Vilmen, C., Micallef, J. P., Perrey, S., Cozzone, Patrick J, Bendahan, D.
Přispěvatelé: Centre de résonance magnétique biologique et médicale (CRMBM), Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS)
Jazyk: angličtina
Rok vydání: 2012
Zdroj: Experimental Physiology
Experimental Physiology, Wiley-Blackwell, 2012, 97 (8), pp.955-69. ⟨10.1113/expphysiol.2011.062927⟩
Experimental Physiology, 2012, 97 (8), pp.955-69. ⟨10.1113/expphysiol.2011.062927⟩
ISSN: 0958-0670
1469-445X
DOI: 10.1113/expphysiol.2011.062927⟩
Popis: Layec, Gwenael Bringard, Aurelien Yashiro, Kazuya Le Fur, Yann Vilmen, Christophe Micallef, Jean-Paul Perrey, Stephane Cozzone, Patrick J Bendahan, David Research Support, Non-U.S. Gov't England Experimental physiology Exp Physiol. 2012 Aug;97(8):955-69. Epub 2012 Apr 11.; To better understand the mechanisms underlying the pulmonary O(2) uptake (V(O(2P))) slow component during high-intensity exercise, we used (31)P magnetic resonance spectroscopy, gas exchange, surface electromyography and near-infrared spectroscopy measurements to examine the potential relationship between the slow components of V(O(2P)) and phosphocreatine (PCr), muscle recruitment and tissue oxygenation in endurance-trained athletes and sedentary subjects. Specifically, six endurance-trained and seven sedentary subjects performed a dynamic high-intensity exercise protocol during 6 min at an exercise intensity corresponding to 35-40% of knee-extensor maximal voluntary contraction. The slow component of V(O(2P))(117 +/- 60 ml min(-1), i.e. 20 +/- 10% of the total response) was associated with a paradoxical PCr resynthesis in endurance-trained athletes (-0.90 +/- 1.27 mm, i.e. -12 +/- 16% of the total response). Meanwhile, oxygenated haemoglobin increased throughout the second part of exercise and was significantly higher at the end of exercise compared with the value at 120 s (P < 0.05), whereas the integrated EMG was not significantly changed throughout exercise. In sedentary subjects, a slow component was simultaneously observed for V(O(2P)) and [PCr] time-dependent changes (208 +/- 14 ml min(-1), i.e. 38 +/- 18% of the total V(O(2P))response, and 1.82 +/- 1.39 mm, i.e. 16 +/- 13% of the total [PCr] response), but the corresponding absolute or relative amplitudes were not correlated. The integrated EMG was significantly increased throughout exercise in sedentary subjects. Taken together, our results challenge the hypothesis of a mechanistic link between [PCr] and V(O(2P)) slow components and demonstrate that, as a result of a tighter metabolic control and increased O(2) availability, the [PCr] slow component can be minimized in endurance-trained athletes while the V(O(2P)) slow component occurs.
Databáze: OpenAIRE
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