Document Detail

Effects of pedal frequency on estimated muscle microvascular O2 extraction.
MedLine Citation:
PMID:  16369819     Owner:  NLM     Status:  MEDLINE    
An increase in muscle contraction frequency could limit muscle blood flow QM compromising the matching of QM and muscle oxygen uptake VO2M. This study examined the effects of pedal cadence on skeletal muscle oxygenation at low, moderate and peak exercise. Nine healthy subjects [24.7+/-6.3 years (SD)] performed incremental cycling exercise at 60 and 100 rpm. Pulmonary VO2(VO2P) was measured breath-by-breath and vastus lateralis oxygenation was determined by near-infrared spectroscopy (NIRS). The deoxyhemoglobin signal ([HHb]) from NIRS was used to estimate microvascular O2 extraction (i.e., [HHb] proportional, variant VO2M/QM). The VO2P and [HHb] for low, moderate and at peak exercise were determined. The VO2P at 60 rpm (low=0.64+/-0.13, moderate=2.03+/-0.38 and peak=3.39+/-0.84 l/min) were lower (P<0.01) than at 100 rpm (1.29+/-0.23, 2.14+/-0.39 and 3.54+/-0.88 l/min, respectively). There was a progressive increase in [HHb] from low to peak exercise. However, there was no significant difference (ANOVA, P=0.94) for the 60 (in microM, low=24.0+/-9.5, moderate=30.5+/-13.8 and peak=36.7+/-16.5) and 100 contractions/min (in microM, low=25.7+/-11.6, moderate=32.1+/-14.0 and peak=35.4+/-16.5). We conclude that vastus lateralis O2 extraction was similar at 60 and 100 cpm, suggesting that the VO2M/QM in the microcirculation was not altered and, presumably, no impairment of QM occurred with the increase in pedal frequency.
Leonardo F Ferreira; Barbara J Lutjemeier; Dana K Townsend; Thomas J Barstow
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2005-12-21
Journal Detail:
Title:  European journal of applied physiology     Volume:  96     ISSN:  1439-6319     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2006 Mar 
Date Detail:
Created Date:  2006-03-14     Completed Date:  2006-06-29     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:  558-63     Citation Subset:  IM    
Department of Kinesiology, Kansas State University, Manhattan, KS, 66506-0302, USA.
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MeSH Terms
Exercise Test
Hemoglobins / metabolism
Microcirculation / physiology
Muscle Contraction / physiology*
Muscle, Skeletal / blood supply,  metabolism*
Oxygen / metabolism*
Oxygen Consumption / physiology*
Physical Exertion / physiology*
Regional Blood Flow / physiology
Spectroscopy, Near-Infrared
Reg. No./Substance:
0/Hemoglobins; 7782-44-7/Oxygen; 9008-02-0/deoxyhemoglobin

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

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