BACKWARD EXTRAPOLATION OF VO2 MAX VALUES FROM THE O-2 RECOVERY CURVE

Abstract

To validate a method for measuring human .ovrhdot.VO2 max [maximum O2 consumption] in field conditions, .ovrhdot.VO2 max obtained by backward extrapolation of the O2 recovery curve at time 0 of recovery (BE) was compared to .ovrhdot.VO2 max measured directly at the end of a continuous multtistage test (exercise). The optimal way to determine .ovrhdot.VO2 max was by using a single component exponential least-squares regression of the 1st 3 or 4 20 s recovery values. When a 3-way valve was used to collect expired air immediately at the start of recovery (n [number] = 20), BE .ovrhdot.VO2 max (.hivin.X .+-. SD = 56.5 .+-. 7.4 ml kg-1 min-1) was not significantly different from exercise .ovrhdot.VO2 max (56.1 .+-. 7.6). When subjects (n = 16) connected themselves to another breathing valve immediately at the end of the test to simulate field conditions BE and exercise .ovrhdot.VO2 max were similar (63.9 .+-. 6.7 and 63.1 .+-. 7.0, respectively) as long as a 3 s correction was made for the delay by this procedure. BE and exercise .ovrhdot.VO2 max were 59.8 .+-. 8 and 59.2 .+-. 8.1 for the 36 subjects; the Pearson''s correlation coefficient was 0.92. BE .ovrhdot.VO2 max measured on 11 additional runners tested on a track (62.6 .+-. 13) yielded similar results as exercise .ovrhdot.VO2 max measured on the treadmill the same protocol (61.2 .+-. 13.3). The backward extrapolation method appears to be valid to measure .ovrhdot.VO2 max when the air collecting equipment might otherwise be cumbersome during actual sport and/or laboratory conditions.