Mechanisms of Attenuation of Pulmonary V'O2 Slow Component in Humans after Prolonged Endurance Training

• Published in: PloS one Vol. 11; no. 4; p. e0154135
• Main Authors: Zoladz, Jerzy A, Majerczak, Joanna, Grassi, Bruno, Szkutnik, Zbigniew, Korostyński, Michał, Gołda, Sławomir, Grandys, Marcin, Jarmuszkiewicz, Wiesława, Kilarski, Wincenty, Karasinski, Janusz, Korzeniewski, Bernard
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.04.2016; Public Library of Science (PLoS)
• Subjects: Acidification; Biochemistry; Bioenergetics; Biology; Biology and Life Sciences; Biosynthesis; Blotting, Western; Computer and Information Sciences; Computer Simulation; Cycles; Durability; Endurance; Enzymes; Exercise; Exercise - physiology; Exercise Test; Gene Expression; Heart Rate - physiology; Humans; Kinases; Kinetics; Lactates - blood; Lactic acid; Lung - metabolism; Lung - physiology; Male; Medicine and Health Sciences; Metabolism; Metabolites; Models, Biological; mRNA; Muscle Proteins - metabolism; Muscles; Musculoskeletal system; Oxidative Phosphorylation; Oxygen; Oxygen Consumption - genetics; Oxygen Consumption - physiology; Oxygen uptake; Phosphorylation; Physical education; Physical Endurance - genetics; Physical Endurance - physiology; Physical training; Physiology; Quadriceps Muscle - metabolism; Quadriceps Muscle - physiology; Reaction kinetics; Rehabilitation; Reverse Transcriptase Polymerase Chain Reaction; Rodents; Running - physiology; Sarcoplasmic Reticulum Calcium-Transporting ATPases - metabolism; Skeletal muscle; Studies; Training; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - genetics; Vascular endothelial growth factor receptor 2; Young Adult; Zoology; Poland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0154135

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.