Duration of %26quot;Phase I%26quot; (V) over dotO(2p): a comparison of methods used in its estimation and the effects of varying moderate-intensity work rate

作者：Spencer Matthew D; Gravelle Braden M R; Murias Juan M; Zerbini Livio; Pogliaghi Silvia; Paterson Donald H^*

来源：American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, 2013, 304(3): R238-R247.

DOI：10.1152/ajpregu.00419.2012

• (V) over dotO(2) kinetics
• cardiodynamic phase
• moderate-intensity exercise

Spencer MD, Gravelle BM, Murias JM, Zerbini L, Pogliaghi S, Paterson DH. Duration of %26quot; Phase I%26quot; (V) over dotO(2p): a comparison of methods used in its estimation and the effects of varying moderate-intensity work rate. Am J Physiol Regul Integr Comp Physiol 304: R238-R247, 2013. First published December 12, 2012; doi: 10.1152/ ajpregu. 00419.2012.The present study was designed to investigate whether absolute work rate (WR) affects Phase I pulmonary oxygen uptake ((V) over dotO(2p)) duration during moderate-intensity (Mod) exercise and to compare two methods for estimating Phase I (V) over dotO(2p) duration (PI-Dur). Fourteen males (24 +/- 5 yr) each completed 4-8 repetitions of Mod transitions from 20 W to 50, 70, 90, 110, and 130 W. PI-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 three independent reviewers, and the average (Avg) of the two most similar values]; or 2) the intersection (time delay, TD) of the first and second components in a biexponential nonlinear regression of the entire (V) over dotO(2p) response from exercise onset. PI-Dur did not differ among WRs (P %26lt; 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 (50 W, 21 +/- 6 vs. 23 +/- 10 s; 70 W, 23 +/- 9 vs. 23 +/- 7 s; 90 W, 24 +/- 3 vs. 22 +/- 5 s; 110 W, 23 +/- 6 vs. 22 +/- 6 s; 130 W, 21 +/- 6 vs. 21 +/- 7 s; P %26lt; 0.05 for Avg and TD, respectively). Broad limits of agreement within Bland-Altman plots revealed relatively weak agreement among reviewers for individual estimation of PI-Dur. A nonsignificant correlation coefficient (r = 0.13) and broad limits of agreement suggest disparity between individual Avg and TD estimates of PI-Dur. The present data do not support a role for Mod WR in determining PI-Dur per se. Furthermore, this study illustrated a poor agreement of PI-Dur estimates derived from two different, but accepted methods.

• 出版日期2013-2