Influence of test duration on oxygen uptake attained during treadmill running

Abstract

Previous investigations have revealed that in well-trained middle-distance runners, oxygen uptake (VO 2 ) does not attain maximal values (VO 2max ) in exhaustive treadmill trials where the VO 2 demand exceeds VO 2max . To date, this shortfall in the VO 2 attained has been demonstrated in trials as short as 2 min in duration. In this study, we investigated whether a reduction in exhaustive test duration influences the VO 2 attained during running on a treadmill. Six middle-distance runners participated in the study, completing an exhaustive 400 m and 800 m trial. These trials, together with a progressive test to determine VO 2max , were completed in a counterbalanced order. Oxygen uptakes attained during the 400 m and 800 m trials were compared to examine the influence of exhaustive test duration. A plateau in VO 2 was observed in all participants for the progressive test, demonstrating the attainment of VO 2max . The mean speed, duration, and resulting distance in the constant-speed exhaustive trials were 25.8 km × h (1 (s01.2), 55.8 s (s 02.3), and 400.2 m (s 020.2) for the 400 m trial, and 24.3 km × h (1 (s00.8), 108.4 s (s 021.2), and 730.1 m (s0129.1) for the 800 m trial, respectively. A paired-samples t-test revealed a significantly different (P00.018)%VO 2max was attained for the 400 m (85.7%, s 03.0) and 800 m (89.1%, s05.0) trials. In conclusion, VO 2 did not reach VO 2max during the exhaustive constant-speed 400 m and 800 m trials, but the test duration does influence the%VO 2max achieved. Specifically, the VO 2 attained becomes progressively further below VO 2max as trial duration is reduced, such that 89% and 86% VO 2max is achieved in exhaustive 800 m and 400 m constant-speed trials, respectively.

Maximal Oxygen Uptake Is Achieved in Hypoxia but Not Normoxia during an Exhaustive Severe Intensity Run

“…It is assumed that during exercise within the severe or extreme intensity domain, will project exponentially toward the maximal rate of pulmonary oxygen uptake ( ) until is achieved, or exhaustion occurs (Whipp, 1994 ; Gaesser and Poole, 1996 ; Poole and Richardson, 1997 ; Hill and Ferguson, 1999 ; Jones and Burnley, 2009 ). However, research utilizing exhaustive constant work rate (CWR) treadmill running of ~2 min and highly aerobically trained middle distance runners ( ≥ 60 ml.kg −1 .min −1 ) has found that does not achieve despite sufficient time for the full response to develop (Draper and Wood, 2005a , b ; Sandals et al, 2006 ; James et al, 2007a , b , 2008 ). Instead, a submaximal steady state is achieved following ~1 min of exercise with no evidence of a further increase in (Draper and Wood, 2005b ).…”