RESUMEN
PURPOSE: To identify the optimal aerobic determinants of elite, middle-distance running (MDR) performance, using proportional allometric models. METHODS: Sixty-two national and international male and female 800-m and 1500-m runners undertook an incremental exercise test to volitional exhaustion. Mean submaximal running economy (ECON), speed at lactate threshold (speedLT), maximum oxygen uptake (.VO(2max)), and speed associated with .VO(2max) (speed.VO(2max)) were paired with best performance times recorded within 30 d. The data were analyzed using a proportional power-function ANCOVA model. RESULTS: The analysis identified significant differences in running speeds with main effects for sex and distance, with .VO(2max) and ECON as the covariate predictors (P < 0.0001). The results suggest a proportional curvilinear association between running speed and the ratio (.VO(2max).ECON(-0.71))(0.35) explaining 95.9% of the variance in performance. The model was cross-validated with a further group of highly trained MDR, demonstrating strong agreement (95% limits, 0.05 +/- 0.29 m.s(-1)) between predicted and actual performance speeds (R(2) = 93.6%). The model indicates that for a male 1500-m runner with a .VO(2max) of 3.81 L.min(-1) and ECON of 15 L.km(-1) to improve from 250 to 240 s, it would require a change in .VO(2max) from 3.81 to 4.28 L.min(-1), an increase of Delta0.47 L.min(-1). However, improving by the same margin of 10 s from 225 to 215 s would require a much greater increase in .VO(2max), from 5.14 to 5.85 L.min(-1), an increase of Delta0.71 L.min(-1) (where ECON remains constant). CONCLUSION: A proportional curvilinear ratio of .VO(2max) divided by ECON explains 95.9% of the variance in MDR performance.