Alterations in VOmax and the VO plateau with manipulation of sampling interval.
BACKGROUND
The most accepted criterion for confirming attainment of VO(2)max is a plateau in oxygen consumption (VO(2)) at VO(2)max, but its incidence varies.


OBJECTIVE
To compare VO(2)max and VO(2) plateau incidence across various sampling intervals, and to examine predictors of the change in VO(2) (DeltaVO(2)) at VO(2)max.


METHODS
Sedentary, recreationally-active, and endurance-trained subjects (n = 108, age = 24.2 +/- 6.2 year) completed incremental exercise on the treadmill or cycle ergometer. Gas exchange data were obtained breath-by-breath and time-averaged every 15, 30, and 60 s. VO(2)max attainment was verified with the Taylor et al. (1955) criterion (DeltaVO(2) at VO(2)max < or =2.1 ml kg(-1) min(-1)). Multiple regression was used to examine predictors of DeltaVO(2) at VO(2)max.


RESULTS
VO(2) plateau incidence was higher using breath-by-breath (81%) and 15 (91%) and 30 s time averaging (89%) versus 60 s averaging (59%). Compared to 60 s averaging, VO(2)max was significantly higher (P<0.05) when data were obtained breath-by-breath and with 15 and 30 s time-averaging compared to 60 s sampling. VO(2)max was not related to VO(2) plateau incidence. Respiratory rate was a significant predictor of DeltaVO(2) at VO(2)max in endurance-trained subjects.


CONCLUSIONS
More frequent data acquisition revealed higher VO(2)max and incidence of the VO(2) plateau compared to 60 s time averaging. Secondary criteria to verify VO(2)max attainment should not be used, as they do not discern between subjects who do and do not reveal a plateau in VO(2) at VO(2)max.
Astorino
Todd A
TA
Department of Kinesiology, California State University-San Marcos, San Marcos, CA 92096-0001, USA. astorino@csusm.edu
D000328:Adult; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption; D011659:Pulmonary Gas Exchange; D015656:Respiratory Mechanics; D013997:Time Factors; D055815:Young Adult