Step vs. progressive exercise: the kinetics of phosphocreatine hydrolysis in human muscle

Article Article scientifique Article Step vs. progressive exercise: the kinetics of phosphocreatine hydrolysis in human muscle eng 1997 author Binzoni Tiziano 0009-0004-2592-7926 23000 author Hiltbrand Emile 668277 author Yano Tokuo 91645 author Cerretelli Paolo 25401 209-215 10.1046/j.1365-201X.1997.577354000.x 9079151 0001-6772 It is well known that the VO2 readjustment rate of the whole body is faster when carrying out a given constant work load starting from a baseline of moderate exercise than from rest. However, it has not been established whether the above change is the result of faster kinetics of the oxidative machinery or, alternatively, the consequence of a reduced involvement of confounding factors such as anaerobic glycolysis or tissue O2 stores. The problem, earlier approached by chemical methods, was studied in man by 31P-NMRS assessment of the kinetics of phosphocreatine (PC) hydrolysis at the muscle level which is known to reflect the readjustment rate of the oxidative reactions. Twelve normal subjects carried out in a 90 cm bore modified Picker (1.5 T) magnet, a series of contractions by the plantar flexors reaching pre-set submaximal loads either in single steps (constant load, CL) or progressively (incremental exercise. I). If preceding exercise (I), compared to rest, influenced the rate of oxidations, the PC concentration at the target loads would be different for the two exercise modes, reflecting different energy deficits. This was not the case. Thus the present results show that the rate of readjustment of oxidations at the muscle level is not affected by priming exercise confirming previous findings and showing that theoretical models of VO2 control are experimentally applicable to man. Adult Humans Hydrolysis Kinetics Magnetic Resonance Spectroscopy Middle Aged Muscle, Skeletal/metabolism Phosphocreatine/metabolism Physical Exertion/physiology Dewey 616.0757 Dewey 616.8 53 Département de neurosciences fondamentales 21A 62 Département de radiologie et informatique médicale 227 false 184 Groupe Binzoni Tiziano (radiologie) 234 Acta Physiologica Scandinavica 159 3 fb7a1774-63ef-45c7-bf49-01c2522ca559 Article (Published version) Restricted BINZONI_et_al-1997-Acta_Physiologica_Scandinavica.pdf 472893 application/pdf restrictedAccess Faculté de médecine / Section de médecine fondamentale / Département de neurosciences fondamentales Faculté de médecine / Section de médecine clinique / Département de radiologie et informatique médicale

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Step vs. progressive exercise: the kinetics of phosphocreatine hydrolysis in human muscle	Acta Physiologica Scandinavica			1997	543	0

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