Abstract
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.
Citation: Zoladz JA, Majerczak J, Grassi B, Szkutnik Z, Korostyński M, Gołda S, et al. (2016) Mechanisms of Attenuation of Pulmonary V’O2 Slow Component in Humans after Prolonged Endurance Training. PLoS ONE 11(4):
e0154135.
https://doi.org/10.1371/journal.pone.0154135
Editor: Øyvind Sandbakk, Norwegian University of Science and Technology, NORWAY
Received: January 8, 2016; Accepted: April 9, 2016; Published: April 22, 2016
Copyright: © 2016 Zoladz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper.
Funding: This work was supported by the European Union from the resources of the European Regional Development Fund under the Innovative Economy Program (grant coordinated by JCET-UJ, No. POIG.01.01.02-00-069/09). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Description
The study investigates how endurance training affects pulmonary oxygen uptake kinetics.