Document Detail


Exercise performance and VO2 kinetics during upright and recumbent high-intensity cycling exercise.
MedLine Citation:
PMID:  20386919     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study investigated cycling performance and oxygen uptake V(O)₂kinetics between upright and two commonly used recumbent (R) postures, 65 degrees R and 30 degrees R. On three occasions, ten young active males performed three bouts of high-intensity constant-load (85% peak-workload achieved during a graded test) cycling in one of the three randomly assigned postures (upright, 65 degrees R or 30 degrees R). The first bout was performed to fatigue and second and third bouts were limited to 7 min. A subset of seven subjects performed a final constant-load test to failure in the supine posture. Exercise time to failure was not altered when the body inclination was lowered from the upright (13.1 +/- 4.5 min) to 65 degrees R (10.5 +/- 2.7 min) and 30 degrees R (11.5 +/- 4.6 min) postures; but it was significantly shorter in the supine posture (5.8 +/- 2.1 min) when compared with the three inclined postures. Resulting kinetic parameters from a tri-exponential analysis of breath-by-breath V(O)₂data during the first 7 min of exercise were also not different between the three inclined postures. However, inert gas rebreathing analysis of cardiac output revealed a greater cardiac output and stroke volume in both recumbent postures compared with the upright posture at 30 s into the exercise. These data suggest that increased cardiac function may counteract the reduction of hydrostatic pressure from upright approximately 25 mmHg; to 65 degrees R approximately 22 mmHg; and 30 degrees R approximately 18 mmHg such that perfusion of active muscle presumably remains largely unchanged, and also therefore, V(O)₂kinetics and performance during high-intensity cycling.
Authors:
Mikel Egaña; Damien O'Riordan; Stuart A Warmington
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Publication Detail:
Type:  Comparative Study; Journal Article; Randomized Controlled Trial     Date:  2010-04-13
Journal Detail:
Title:  European journal of applied physiology     Volume:  110     ISSN:  1439-6327     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-08-12     Completed Date:  2010-12-13     Revised Date:  2011-01-13    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  39-47     Citation Subset:  IM    
Affiliation:
Department of Physiology, Trinity College Dublin, Dublin 2, Ireland. megana@tcd.ie
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological
Bicycling*
Cardiac Output
Exercise*
Exercise Test
Heart Rate
Humans
Hydrostatic Pressure
Kinetics
Male
Muscle Contraction*
Muscle Fatigue
Muscle, Skeletal / metabolism*
Oxygen / metabolism*
Oxygen Consumption*
Posture*
Stroke Volume
Supine Position
Young Adult
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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