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Validity of Postexercise Measurements to Estimate Peak VO2 in 200-m and 400-m Maximal Swims.

To assess the validity of postexercise measurements to estimate oxygen uptake (V˙O2) during swimming, we compared V˙O2 measured directly during an all-out 200-m swim with measurements estimated during 200-m and 400-m maximal tests using several methods, including a recent heart rate (HR)/V˙O2 modelling procedure. 25 elite swimmers performed a 200-m maximal swim where V˙O2 was measured using a swimming snorkel connected to a gas analyzer. The criterion variable was V˙O2 in the last 20 s of effort, which was compared with the following V˙O2peak estimates: 1) first 20-s average; 2) linear backward extrapolation (BE) of the first 20 and 30 s, 3×20-s, 4×20-s, and 3×20-s or 4×20-s averages; 3) semilogarithmic BE at the same intervals; and 4) predicted V˙O2peak using mathematical modelling of 0-20 s and 5-20 s during recovery. In 2 series of experiments, both of the HR/V˙O2 modelled values most accurately predicted the V˙O2peak (mean ∆=0.1-1.6%). The BE methods overestimated the criterion values by 4-14%, and the single 20-s measurement technique yielded an underestimation of 3.4%. Our results confirm that the HR/V˙O2 modelling technique, used over a maximal 200-m or 400-m swim, is a valid and accurate procedure for assessing cardiorespiratory and metabolic fitness in competitive swimmers.