Document Detail


Effects of altering pedal frequency on the slow component of pulmonary VO2 kinetics and EMG activity.
MedLine Citation:
PMID:  20432199     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study investigated the effects of pedal frequency on the slow component of pulmonary oxygen uptake ( V O(2)) kinetics during heavy exercise at the same relative intensity. We hypothesized that higher pedal frequency (expected to enhance fast-twitch muscle fiber recruitment) would be associated with greater slow component amplitude (A' (s)), surface electromyography (normalized root mean square; RMS) and blood lactate concentration ([lactate]). Eight subjects performed square-wave transitions to heavy exercise at 35 and 115 rpm. Furthermore, alternated cadences square-wave transitions (35-115 rpm) were performed to examine the potential effects of additional fast-twitch muscle fiber recruitment on the slow component. Significance was accepted when P<0.05. The A' (s) was greater at higher cadences (0.58+/-0.08 and 0.70+/-0.09 L.min (-1) at 115 and 35-115 rpm, respectively) than at 35 rpm (0.35+/-0.04 L.min (-1)). Greater EMG increase over time (DeltaRMS ((10-3 min))) and [lactate] were observed at 115 and 35-115 rpm compared with 35 rpm. There was a significant correlation between A' (s) and overall DeltaRMS ((10-3 min)) for all pedal frequencies combined (r=0.63; P=0.001). Pedal frequency had no effect on time constants or time delays. These findings are consistent with the concept that progressive recruitment of muscle fibers is associated with the V O(2) slow component.
Authors:
D M Hirai; B T Roseguini; F Diefenthaeler; F P Carpes; M A Vaz; E L Ferlin; J P Ribeiro; F Y Nakamura
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-04-29
Journal Detail:
Title:  International journal of sports medicine     Volume:  31     ISSN:  1439-3964     ISO Abbreviation:  Int J Sports Med     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-07-28     Completed Date:  2010-11-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8008349     Medline TA:  Int J Sports Med     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  529-36     Citation Subset:  IM    
Copyright Information:
(c) Georg Thieme Verlag KG Stuttgart . New York.
Affiliation:
Department of Physical Education, State University of Londrina, Londrina, Brazil.
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MeSH Terms
Descriptor/Qualifier:
Adult
Bicycling / physiology*
Electromyography
Exercise Test / methods*
Humans
Male
Muscle Fibers, Fast-Twitch / metabolism
Muscle, Skeletal / metabolism
Oxygen Consumption*
Time Factors

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


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