A New Model for Estimating Peak Oxygen Uptake Based on Postexercise Measurements in Swimming

Assessing cardiopulmonary function during swimming is a complex and cumbersome procedure. Backward extrapolation is often used to predict peak oxygen uptake ((V) over dotO(2peak)) during unimpeded swimming, but error can derive from a delay at the onset of (V) over dotO(2) recovery. The authors assessed the validity of a mathematical model based on heart rate (HR) and postexercise (V) over dotO(2) kinetics for the estimation of (V) over dotO(2peak) during exercise. Methods: 34 elite swimmers performed a maximal front-crawl 200-m swim. (V) over dotO(2) was measured breath by breath and HR from beat-to-beat intervals. Data were time-aligned and 1-s-interpolated. Exercise (V) over dotO(2peak) was the average of the last 20 s of exercise. Postexercise (V) over dotO(2) was the first 20-s average during the immediate recovery. Predicted (V) over dotO(2) values (p(V) over dotO(2)) were computed using the equation: p(V) over dotO(2)(t) = (V) over dotO(2)(t) HRend-exereise/HR(t). Average values were calculated for different time intervals and compared with measured exercise (V) over dotO(2)peak. Results: Postexercise (V) over dotO(2) (0-20 s) underestimated (V) over dotO(2peak) by 3.3% (95% CI = 9.8% underestimation to 3.2% overestimation, mean difference = -116 mL/min, SEE = 4.2%, P =.001). The best (V) over dotO(2)peak estimates were offered by p(V) over dotO(2) from 0 to 20 s (r(2) = .96, mean difference = 17 mL/min, SEE = 3.8%). Conclusions: The high correlation (r(2) = .86-.96) and agreement between exercise and predicted (V) over dotO(2) support the validity of the model, which provides accurate (V) over dotO(2peak) estimations after a single maximal swim while avoiding the error of backward extrapolation and allowing the subject to swim completely unimpeded.