Document Detail

Influence of intensity fluctuation on exercise metabolism.
MedLine Citation:
PMID:  17323070     Owner:  NLM     Status:  MEDLINE    
This investigation was undertaken to examine the influence of intensity fluctuation on metabolic responses during and after exercise. Twenty-four males and 24 females were randomly assigned into one of the four groups consisting of 12 subjects of equal gender. Each group performed one of four 30-min exercise protocols: (1) cycling at a constant power output of 75 W (P1), (2) cycling with power output alternating between 50 and 100 W every 5 min (P2), (3) same as P2 except power output was alternated in a reverse order (P3), and (4) same as P2 except power output was alternated between 25 and 125 W (P4). Each exercise session was followed by a 25-min recovery and all protocols yielded the same mechanical work. Oxygen uptake (VO(2)), heart rate (HR), respiratory exchange ratio (RER), and plasma lactate concentrations ([La]) were measured at rest and during exercise and recovery. Ratings of perceived exertion (RPE) were recorded during exercise only. During exercise, VO(2), HR and RPE did not differ across the four protocols. RER was higher (P < 0.05) in P4 than P1 and P2. [La] was higher (P < 0.05) in P4 than P1 and P3. During recovery, VO(2) were lower (P < 0.05) in P1 than P2, P3, and P4, while [La] was higher in P4 than P3. When the total workload was equated, intensity fluctuation exerted no added effect upon metabolic responses during exercise, but provoked greater energy expenditure following exercise. Reversing the order or increasing the magnitude of intensity fluctuation would not further alter metabolic consequences.
Jie Kang; Gerald T Mangine; Nicholas A Ratamess; Avery D Faigenbaum; Jay R Hoffman
Publication Detail:
Type:  Journal Article; Randomized Controlled Trial     Date:  2007-02-24
Journal Detail:
Title:  European journal of applied physiology     Volume:  100     ISSN:  1439-6319     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2007 Jun 
Date Detail:
Created Date:  2007-05-03     Completed Date:  2007-10-18     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  253-60     Citation Subset:  IM    
Human Performance Laboratory, Department of Health and Exercise Science, The College of New Jersey, Ewing, NJ 08068, USA.
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MeSH Terms
Energy Metabolism / physiology*
Exercise / physiology*
Heart Rate / physiology
Lactates / blood
Oxygen Consumption / physiology
Physical Exertion / physiology*
Pulmonary Gas Exchange / physiology
Rest / physiology
Reg. No./Substance:

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