Cargando…

Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients

The oxygen cost of transport per unit distance (CoT; mL·kg(-1)·km(-1)) shows a U-shaped curve as a function of walking speed (v), which includes a particular walking speed minimizing the CoT, so called economical speed (ES). The CoT-v relationship in running is approximately linear. These distinctiv...

Descripción completa

Detalles Bibliográficos
Autores principales: Abe, Daijiro, Fukuoka, Yoshiyuki, Horiuchi, Masahiro
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4575035/
https://www.ncbi.nlm.nih.gov/pubmed/26383249
http://dx.doi.org/10.1371/journal.pone.0138154
_version_ 1782390714262355968
author Abe, Daijiro
Fukuoka, Yoshiyuki
Horiuchi, Masahiro
author_facet Abe, Daijiro
Fukuoka, Yoshiyuki
Horiuchi, Masahiro
author_sort Abe, Daijiro
collection PubMed
description The oxygen cost of transport per unit distance (CoT; mL·kg(-1)·km(-1)) shows a U-shaped curve as a function of walking speed (v), which includes a particular walking speed minimizing the CoT, so called economical speed (ES). The CoT-v relationship in running is approximately linear. These distinctive walking and running CoT-v relationships give an intersection between U-shaped and linear CoT relationships, termed the energetically optimal transition speed (EOTS). This study investigated the effects of subtracting the standing oxygen cost for calculating the CoT and its relevant effects on the ES and EOTS at the level and gradient slopes (±5%) in eleven male trained athletes. The percent effects of subtracting the standing oxygen cost (4.8 ± 0.4 mL·kg(-1)·min(-1)) on the CoT were significantly greater as the walking speed was slower, but it was not significant at faster running speeds over 9.4 km·h(-1). The percent effect was significantly dependent on the gradient (downhill > level > uphill, P < 0.001). The net ES (level 4.09 ± 0.31, uphill 4.22 ± 0.37, and downhill 4.16 ± 0.44 km·h(-1)) was approximately 20% slower than the gross ES (level 5.15 ± 0.18, uphill 5.27 ± 0.20, and downhill 5.37 ± 0.22 km·h(-1), P < 0.001). Both net and gross ES were not significantly dependent on the gradient. In contrast, the gross EOTS was slower than the net EOTS at the level (7.49 ± 0.32 vs. 7.63 ± 0.36 km·h(-1), P = 0.003) and downhill gradients (7.78 ± 0.33 vs. 8.01 ± 0.41 km·h(-1), P < 0.001), but not at the uphill gradient (7.55 ± 0.37 vs. 7.63 ± 0.51 km·h(-1), P = 0.080). Note that those percent differences were less than 2.9%. Given these results, a subtraction of the standing oxygen cost should be carefully considered depending on the purpose of each study.
format Online
Article
Text
id pubmed-4575035
institution National Center for Biotechnology Information
language English
publishDate 2015
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-45750352015-09-25 Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients Abe, Daijiro Fukuoka, Yoshiyuki Horiuchi, Masahiro PLoS One Research Article The oxygen cost of transport per unit distance (CoT; mL·kg(-1)·km(-1)) shows a U-shaped curve as a function of walking speed (v), which includes a particular walking speed minimizing the CoT, so called economical speed (ES). The CoT-v relationship in running is approximately linear. These distinctive walking and running CoT-v relationships give an intersection between U-shaped and linear CoT relationships, termed the energetically optimal transition speed (EOTS). This study investigated the effects of subtracting the standing oxygen cost for calculating the CoT and its relevant effects on the ES and EOTS at the level and gradient slopes (±5%) in eleven male trained athletes. The percent effects of subtracting the standing oxygen cost (4.8 ± 0.4 mL·kg(-1)·min(-1)) on the CoT were significantly greater as the walking speed was slower, but it was not significant at faster running speeds over 9.4 km·h(-1). The percent effect was significantly dependent on the gradient (downhill > level > uphill, P < 0.001). The net ES (level 4.09 ± 0.31, uphill 4.22 ± 0.37, and downhill 4.16 ± 0.44 km·h(-1)) was approximately 20% slower than the gross ES (level 5.15 ± 0.18, uphill 5.27 ± 0.20, and downhill 5.37 ± 0.22 km·h(-1), P < 0.001). Both net and gross ES were not significantly dependent on the gradient. In contrast, the gross EOTS was slower than the net EOTS at the level (7.49 ± 0.32 vs. 7.63 ± 0.36 km·h(-1), P = 0.003) and downhill gradients (7.78 ± 0.33 vs. 8.01 ± 0.41 km·h(-1), P < 0.001), but not at the uphill gradient (7.55 ± 0.37 vs. 7.63 ± 0.51 km·h(-1), P = 0.080). Note that those percent differences were less than 2.9%. Given these results, a subtraction of the standing oxygen cost should be carefully considered depending on the purpose of each study. Public Library of Science 2015-09-18 /pmc/articles/PMC4575035/ /pubmed/26383249 http://dx.doi.org/10.1371/journal.pone.0138154 Text en © 2015 Abe et al http://creativecommons.org/licenses/by/4.0/ 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 properly credited.
spellingShingle Research Article
Abe, Daijiro
Fukuoka, Yoshiyuki
Horiuchi, Masahiro
Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients
title Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients
title_full Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients
title_fullStr Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients
title_full_unstemmed Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients
title_short Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients
title_sort economical speed and energetically optimal transition speed evaluated by gross and net oxygen cost of transport at different gradients
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4575035/
https://www.ncbi.nlm.nih.gov/pubmed/26383249
http://dx.doi.org/10.1371/journal.pone.0138154
work_keys_str_mv AT abedaijiro economicalspeedandenergeticallyoptimaltransitionspeedevaluatedbygrossandnetoxygencostoftransportatdifferentgradients
AT fukuokayoshiyuki economicalspeedandenergeticallyoptimaltransitionspeedevaluatedbygrossandnetoxygencostoftransportatdifferentgradients
AT horiuchimasahiro economicalspeedandenergeticallyoptimaltransitionspeedevaluatedbygrossandnetoxygencostoftransportatdifferentgradients