Effect of recovery time on V˙O2documentclass12pt{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$dot{V}{text{O}}_{2}$$end{document}-ON kinetics in humans at the onset of moderate-intensity cycling exercise

摘要

Abstract Purpose τ of the primary phase of V˙O2Adocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$dot{V}{text{O}}_{{2{text{A}}}}$$end{document} kinetics during square-wave, moderate-intensity exercise mirrors that of PCr splitting (τPCr). Pre-exercise [PCr] and the absolute variations of PCr (?[PCr]) occurring during transient have been suggested to control τPCr and, in turn, to modulate V˙O2Adocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$dot{V}{text{O}}_{{2{text{A}}}}$$end{document} kinetics. In addition, V˙O2Adocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$dot{V}{text{O}}_{{2{text{A}}}}$$end{document} kinetics may be slower when exercise initiates from a raised metabolic level, i.e., from a less-favorable energetic state. We verified the hypothesis that: (i) pre-exercise [PCr], (ii) pre-exercise metabolic rate, or (iii) ?[PCr] may affect the kinetics of muscular oxidative metabolism and, therefore, τ.Methods To this aim, seven active males (23.0 yy?±?2.3; 1.76?m?±?0.06, V˙O2maxdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$dot{V}{text{O}}_{2max }$$end{document}: 3.32 L min?1?±?0.67) performed three repetitions of series consisting of six 6-min step exercise transitions of identical workload interspersed with different times of recovery: 30, 60, 90, 120, 300?s.Results Mono-exponential fitting was applied to breath-by-breath V˙O2Adocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$dot{V}{text{O}}_{{2{text{A}}}}$$end{document}, so that τ was determined. τ decays as a first-order exponential function of the time of recovery (τ?=?109.5?×?e(?t/14.0)?+?18.9 r2?=?0.32) and linearly decreased as a function of the estimated pre-exercise [PCr] (τ?= ??1.07 [PCr]?+?44.9, r2?=?0.513, P?