Quantification of aerobic determinants of performance in post-pubertal adolescent middle-distance runners

Purpose The use of oxygen cost ( O ˙ aero ) parameters to predict endurance performance has recently been criticized. Instead, it is suggested that aerobic energy cost ( E ˙ aero ) provides greater validity; however, a comparison of these quantification methods has not previously been made. Methods Fifty-six male ( n = 34) and female ( n = 22) competitive adolescent (17 ± 1 years) middle-distance runners participated in a sub-maximal and maximal incremental treadmill test. Running economy (RE) was measured at the speed corresponding to lactate turnpoint, and the three speeds prior. Maximal oxygen uptake ( V ˙ O 2 max), speed at V ˙ O 2 max and fraction of V ˙ O 2 max utilized across a range of intensities, and speeds from 0.8, 1.5 and 3 km races were also quantified. RE and fractional utilization were calculated in units of O ˙ aero and E ˙ aero . Results Multiple linear regression models demonstrated no discernible difference in the predictive capability of RE, fractional utilization and V ˙ O 2 max when expressed as O ˙ aero or E ˙ aero in both sexes. When plotted as a function of running speed, O ˙ aero displayed a stepwise decrease ( F = 11.59, p