Document Detail

Duration of 'Phase I' VO2p: a comparison of methods used in its estimation and the effects of varying moderate-intensity work rate.
MedLine Citation:
PMID:  23235325     Owner:  NLM     Status:  Publisher    
The present study was designed to investigate whether absolute work rate (WR) affects Phase I pulmonary oxygen uptake (VO(2p)) duration during moderate-intensity (Mod) exercise, and to compare two methods for estimating Phase I VO(2p) duration (P(I-Dur)). Fourteen males (24±5 yrs) each completed 4-8 repetitions of Mod transitions from 20W to 50, 70, 90, 110 and 130W. P(I-Dur) was identified by: (1) a marked decrease in both respiratory exchange ratio and end-tidal partial pressure of O(2) following exercise onset (i.e., visual inspection of 3 independent reviewers, and the average (Avg) of the two most similar values); or (2) the intersection (TD) of the first and second components in a bi-exponential non-linear regression of the entire VO(2p) response from exercise onset. P(I-Dur) did not differ amongst WRs (p>0.05), regardless of the estimation method used. No differences were detected between Avg and TD (time in s) at any of the five WRs (50W, 21±6 vs. 23±10; 70W, 23±9 vs. 23±7; 90W, 24±3 vs. 22±5; 110W, 23±6 vs. 22±6; 130W, 21±6 vs. 21±7 s; p>0.05 for Avg and TD, respectively). Broad limits of agreement within Bland-Altman plots revealed relatively weak agreement amongst reviewers for individual estimation of P(I-Dur). A non-significant correlation coefficient (r=0.13) and broad limits of agreement suggest disparity between individual Avg and TD estimates of P(I-Dur). The present data do not support a role for Mod WR in determining P(I-Dur) per se. Further, this study illustrated a poor agreement of P(I-Dur) estimates derived from two different, but accepted methods.
Matthew D Spencer; Braden M R Gravelle; Juan M Murias; Livio Zerbini; Silvia Pogliaghi; Donald H Paterson
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-12-12
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  -     ISSN:  1522-1490     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-12-13     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
1The University of Western Ontario.
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