A New Model for Estimating Peak Oxygen Uptake Based on Post-Exercise Measurements in Swimming

PURPOSE: Assessing cardiopulmonary function during swimming is a complex and cumbersome procedure. Backward extrapolation is often used for predicting peak oxygen uptake (VO2peak) during unimpeded swimming, but error can derive from a delay at the onset of VO2 recovery. We assessed the validity of a mathematical model based on heart rate (HR) and post-exercise VO2 kinetics for the estimation of VO2peak during exercise.\n\nMETHODS: 34 elite swimmers performed a maximal front crawl 200-m swim. VO2 was measured breath-by-breath and HR from beat-to-beat intervals. Data were time aligned and 1-s interpolated. Exercise VO2peak was the average of the last 20 s of exercise. Post-exercise VO2 was the first 20-s average during the immediate recovery. Predicted VO2 values (pVO2) were computed using the equation: pVO2(t) = VO2 (t) HRendexercise/HR(t). Average values were calculated for different time intervals and compared to measured exercise VO2peak.\n\nRESULTS: Post-exercise VO2 (0-20 s) underestimated VO2peak by 3.3% (95% CI = -9.8 under- to 3.2% overestimation; mean difference = -116 ml·min-1; SEE = 4.2%; p = .001). The best VO2peak estimates were offered by pVO2peak from 0-20 s (r2 = .96; mean diff. = 17 ml·min-1; SEE = 3.8%).\n\nCONCLUSIONS: The high correlation (r2 = .86-.96) and agreement between exercise and predicted VO2 support the validity of the model, which provides accurate VO2peak estimations after a single maximal swim whilst avoiding the error of backward extrapolation and allowing the subject to swim completely unimpeded.