| Effects of prior heavy-intensity exercise on oxygen uptake and muscle deoxygenation kinetics of a subsequent heavy-intensity cycling and knee-extension exercise. | |
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MedLine Citation:
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PMID: 22269026 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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This study examined the effects of prior heavy-intensity exercise on the adjustment of pulmonary oxygen uptake (VO(2p)) and muscle deoxygenation Δ[HHb] during the transition to subsequent heavy-intensity cycling (CE) or knee-extension (KE) exercise. Nine young adults (aged 24 ± 5 years) performed 4 repetitions of repeated bouts of heavy-intensity exercise separated by light-intensity CE and KE, which included 6 min of baseline exercise, a 6-min step of heavy-intensity exercise (H1), 6-min recovery, and a 6-min step of heavy-intensity exercise (H2). Exercise was performed at 50 r·min(-1) or contractions per minute per leg. Oxygen uptake (VO(2)) mean response time was ∼20% faster (p < 0.05) during H2 compared with H1 in both modalities. Phase 2 time constants (τ) were not different between heavy bouts of CE (H1, 29.6 ± 6.5 s; H2, 28.0 ± 4.6 s) or KE exercise (H1, 31.6 ± 6.7 s; H2, 29.8 ± 5.6 s). The VO(2) slow component amplitude was lower (p < 0.05) in H2 in both modalities (CE, 0.19 ± 0.06 L·min(-1); KE, 0.12 ± 0.07 L·min(-1)) compared with H1 (CE, 0.29 ± 0.09 L·min(-1); KE, 0.18 ± 0.07 L·min(-1)), with the contribution of the slow component to the total VO(2) response reduced (p < 0.05) in H2 during both exercise modes. The effective τHHb was similar between bouts for CE (H1, 18.2 ± 3.0 s; H2, 18.0 ± 3.6 s) and KE exercise (H1, 26.0 ± 7.0 s; H2, 24.0 ± 5.8 s). The ΔHHb slow component was reduced during H2 in both CE and KE (p < 0.05). In conclusion, phase 2 VO(2p) was unchanged with priming exercise; however, a faster mean response time of VO(2p) during the heavy-intensity exercise preceded by a priming heavy-intensity exercise was attributed to a smaller slow component and reduced muscle deoxygenation indicative of improved muscle O(2) delivery during the second bout of exercise. |
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Authors:
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Sarah Margaret Cleland; Juan Manuel Murias; John Michael Kowalchuk; Donald Hugh Paterson |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-24 |
Journal Detail:
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Title: Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Volume: - ISSN: 1715-5312 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-24 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101264333 Medline TA: Appl Physiol Nutr Metab Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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a Canadian Centre for Activity and Aging, University of Western Ontario, London, ON N6A 5B9, Canada. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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