The validation of backward extrapolation of submaximal oxygen consumption from the oxygen recovery curve

The purpose of this study was to determine the validity and practicality of exponential vs linear backward extrapolation of the O2 recovery curve for prediction of exercise oxygen consumption (VO2). Eight men and women, age 20.1, 0.9 years, body mass 66.0, 2.5 kg (mean, SEM), completed seven bouts of cycle ergometer exercise at submaximal power outputs ranging from 50 to 175 W. Respiratory gases were collected from each subject during exercise and recovery. The monoexponential extrapolation of five recovery samples (r2 = 0.85) and linear extrapolation of one recovery sample taken during the first 20-s of recovery (r2 = 0.83) accounted for similar amounts of variance in predicting exercise VO2. The linear regression equation was the most practical predictor, as only one recovery gas sample was necessary and it did not require the complicated mathematical techniques used in exponential regression.