Influence of increment magnitude and exercise intensity on VO2 kinetics, time to steady state, and muscle oxygenation

Craig McNulty, Robert Robergs, David Morris

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2 Citations (Scopus)
5 Downloads (Pure)

Abstract

The purpose of this study was to quantify the oxygen uptake (VO2) kinetics to steady state across the full range of sub-ventilatory threshold (VT) work rates. Twelve trained males participated in two separate series of five bouts of cycling. One trial (DM) involved 10 min at a percentage of their VT. The second trial involved five bouts at an increasing baseline intensity for 5 min (SM1), followed by an increase of 30% of VT for 10 min (SM2). The VO2 kinetics was quantified by the mono-exponential time constant (tau, τ) as well as a new method for time to steady state (TTSS). For DM, τ increased significantly from 30% and 45%VT (31 ± 22 and 33 ± 15 sec, respectively) between 60% to 90%VT (42 ± 16, 53 ± 29, 74 ± 25 sec for 60%, 75%, and 90%VT, respectively). For SM1, τ increased significantly from 40% (41 ± 16 sec) to 60%VT (74 ± 25 sec). For SM2, τ increased significantly between 60% (44 ± 11 sec) to 80%, and 90%VT (92 ± 41 and 151 ± 83 sec, respectively), and from 70% (54 ± 38 sec) to 90%VT (151 ± 83 sec). The data revealed a clear increase in τ as intensity increased, revealing a more complex VO2 response than previously documented.
Original languageEnglish
Pages (from-to)37-58
Number of pages22
JournalJournal of Exercise Physiology Online
Volume18
Issue number5
Publication statusPublished - Oct 2015

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title = "Influence of increment magnitude and exercise intensity on VO2 kinetics, time to steady state, and muscle oxygenation",
abstract = "The purpose of this study was to quantify the oxygen uptake (VO2) kinetics to steady state across the full range of sub-ventilatory threshold (VT) work rates. Twelve trained males participated in two separate series of five bouts of cycling. One trial (DM) involved 10 min at a percentage of their VT. The second trial involved five bouts at an increasing baseline intensity for 5 min (SM1), followed by an increase of 30{\%} of VT for 10 min (SM2). The VO2 kinetics was quantified by the mono-exponential time constant (tau, τ) as well as a new method for time to steady state (TTSS). For DM, τ increased significantly from 30{\%} and 45{\%}VT (31 ± 22 and 33 ± 15 sec, respectively) between 60{\%} to 90{\%}VT (42 ± 16, 53 ± 29, 74 ± 25 sec for 60{\%}, 75{\%}, and 90{\%}VT, respectively). For SM1, τ increased significantly from 40{\%} (41 ± 16 sec) to 60{\%}VT (74 ± 25 sec). For SM2, τ increased significantly between 60{\%} (44 ± 11 sec) to 80{\%}, and 90{\%}VT (92 ± 41 and 151 ± 83 sec, respectively), and from 70{\%} (54 ± 38 sec) to 90{\%}VT (151 ± 83 sec). The data revealed a clear increase in τ as intensity increased, revealing a more complex VO2 response than previously documented.",
keywords = "Mono-exponential, Near-infrared-spectroscopy, Steady-state-VO2, VO2-kinetics",
author = "Craig McNulty and Robert Robergs and David Morris",
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year = "2015",
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language = "English",
volume = "18",
pages = "37--58",
journal = "Journal of Exercise Physiology Online",
issn = "1097-9751",
publisher = "American Society of Exercise Physiologists",
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Influence of increment magnitude and exercise intensity on VO2 kinetics, time to steady state, and muscle oxygenation. / McNulty, Craig; Robergs, Robert; Morris, David.

In: Journal of Exercise Physiology Online, Vol. 18, No. 5, 10.2015, p. 37-58.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Influence of increment magnitude and exercise intensity on VO2 kinetics, time to steady state, and muscle oxygenation

AU - McNulty, Craig

AU - Robergs, Robert

AU - Morris, David

N1 - Includes bibliographical references.

PY - 2015/10

Y1 - 2015/10

N2 - The purpose of this study was to quantify the oxygen uptake (VO2) kinetics to steady state across the full range of sub-ventilatory threshold (VT) work rates. Twelve trained males participated in two separate series of five bouts of cycling. One trial (DM) involved 10 min at a percentage of their VT. The second trial involved five bouts at an increasing baseline intensity for 5 min (SM1), followed by an increase of 30% of VT for 10 min (SM2). The VO2 kinetics was quantified by the mono-exponential time constant (tau, τ) as well as a new method for time to steady state (TTSS). For DM, τ increased significantly from 30% and 45%VT (31 ± 22 and 33 ± 15 sec, respectively) between 60% to 90%VT (42 ± 16, 53 ± 29, 74 ± 25 sec for 60%, 75%, and 90%VT, respectively). For SM1, τ increased significantly from 40% (41 ± 16 sec) to 60%VT (74 ± 25 sec). For SM2, τ increased significantly between 60% (44 ± 11 sec) to 80%, and 90%VT (92 ± 41 and 151 ± 83 sec, respectively), and from 70% (54 ± 38 sec) to 90%VT (151 ± 83 sec). The data revealed a clear increase in τ as intensity increased, revealing a more complex VO2 response than previously documented.

AB - The purpose of this study was to quantify the oxygen uptake (VO2) kinetics to steady state across the full range of sub-ventilatory threshold (VT) work rates. Twelve trained males participated in two separate series of five bouts of cycling. One trial (DM) involved 10 min at a percentage of their VT. The second trial involved five bouts at an increasing baseline intensity for 5 min (SM1), followed by an increase of 30% of VT for 10 min (SM2). The VO2 kinetics was quantified by the mono-exponential time constant (tau, τ) as well as a new method for time to steady state (TTSS). For DM, τ increased significantly from 30% and 45%VT (31 ± 22 and 33 ± 15 sec, respectively) between 60% to 90%VT (42 ± 16, 53 ± 29, 74 ± 25 sec for 60%, 75%, and 90%VT, respectively). For SM1, τ increased significantly from 40% (41 ± 16 sec) to 60%VT (74 ± 25 sec). For SM2, τ increased significantly between 60% (44 ± 11 sec) to 80%, and 90%VT (92 ± 41 and 151 ± 83 sec, respectively), and from 70% (54 ± 38 sec) to 90%VT (151 ± 83 sec). The data revealed a clear increase in τ as intensity increased, revealing a more complex VO2 response than previously documented.

KW - Mono-exponential

KW - Near-infrared-spectroscopy

KW - Steady-state-VO2

KW - VO2-kinetics

M3 - Article

VL - 18

SP - 37

EP - 58

JO - Journal of Exercise Physiology Online

JF - Journal of Exercise Physiology Online

SN - 1097-9751

IS - 5

ER -