Mechanisms of Attenuation of Pulmonary V'O2 Slow Component in Humans after Prolonged Endurance Training.
In this study we have examined the effect of prolonged endurance training program on the pulmonary oxygen uptake (V'O2) kinetics during heavy-intensity cycling-exercise and its impact on maximal cycling and running performance. Twelve healthy, physically active men (mean±SD: age 22.33±1.44 years, V'O2peak 3198±458 mL ∙ min-1) performed an endurance training composed mainly of moderate-intensity cycling, lasting 20 weeks. Training resulted in a decrease (by ~5%, P = 0.027) in V'O2 during prior low-intensity exercise (20 W) and in shortening of τp of the V'O2 on-kinetics (30.1±5.9 s vs. 25.4±1.5 s, P = 0.007) during subsequent heavy-intensity cycling. This was accompanied by a decrease of the slow component of V'O2 on-kinetics by 49% (P = 0.001) and a decrease in the end-exercise V'O2 by ~5% (P = 0.005). An increase (P = 0.02) in the vascular endothelial growth factor receptor 2 mRNA level and a tendency (P = 0.06) to higher capillary-to-fiber ratio in the vastus lateralis muscle were found after training (n = 11). No significant effect of training on the V'O2peak was found (P = 0.12). However, the power output reached at the lactate threshold increased by 19% (P = 0.01). The power output obtained at the V'O2peak increased by 14% (P = 0.003) and the time of 1,500-m performance decreased by 5% (P = 0.001). Computer modeling of the skeletal muscle bioenergetic system suggests that the training-induced decrease in the slow component of V'O2 on-kinetics found in the present study is mainly caused by two factors: an intensification of the each-step activation (ESA) of oxidative phosphorylation (OXPHOS) complexes after training and decrease in the ''additional" ATP usage rising gradually during heavy-intensity exercise.
Department of Muscle Physiology, Chair of Physiology and Biochemistry, Faculty of Rehabilitation, University School of Physical Education, Krakow, Poland.
Jerzy A
JA
Zoladz
Department of Muscle Physiology, Chair of Physiology and Biochemistry, Faculty of Rehabilitation, University School of Physical Education, Krakow, Poland.
Joanna
J
Majerczak
Dipartimento di Scienze Mediche e Biologiche, Università degli Studi di Udine, Udine, Italy.
Bruno
B
Grassi
Faculty of Applied Mathematics, AGH-University of Science and Technology, Krakow, Poland.
Zbigniew
Z
Szkutnik
Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland.
Michał
M
Korostyński
Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland.
Sławomir
S
Gołda
Department of Muscle Physiology, Chair of Physiology and Biochemistry, Faculty of Rehabilitation, University School of Physical Education, Krakow, Poland.
Marcin
M
Grandys
Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland.
Wiesława
W
Jarmuszkiewicz
Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Krakow, Poland.
Wincenty
W
Kilarski
Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Krakow, Poland.
Janusz
J
Karasinski
Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
Bernard
B
Korzeniewski
D015153:Blotting, Western; D003198:Computer Simulation; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D015870:Gene Expression; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007773:Lactates / Q000097:blood; D008168:Lung / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D009124:Muscle Proteins / Q000378:metabolism; D010085:Oxidative Phosphorylation; D010101:Oxygen Consumption / Q000235:genetics / Q000502:physiology*; D010807:Physical Endurance / Q000235:genetics / Q000502:physiology*; D052097:Quadriceps Muscle / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012420:Running / Q000502:physiology; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics; D055815:Young Adult
D007773:Lactates; D009124:Muscle Proteins; D042461:Vascular Endothelial Growth Factor A; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; C506943:ATP2A1 protein, human; C506946:ATP2A2 protein, human