The purpose of this study was to determine, based on the time course of the velocity and stride pattern recorded in each 50-m segment of a 400-m competition, whether elite 400-m runners present the same pacing strategy as less successful athletes. Based on video data, 3 different levels of performance were analyzed: world-class, national, and regional levels for both sexes, with each of the 6 groups comprising 5 subjects. The peak velocity was reached by all athletes between the 50- and 100-m marks with mean values of 8.96 and 10.12 m.s for the 5 best women and men, respectively. Peak frequencies were observed in the second and third 50-m segments; peak values were 3.99 +/- 0.13 for the world-class women (WWC) and 4.12 +/- 0.19 for the men (MWC). A stride length of 2.29 +/- 0.04 was observed for the WWC and 2.53 +/- 0.08 for the MWC. The better athletes were able to achieve higher absolute and relative velocities (97.6 +/- 0.5 [MWC] and 96.3 +/- 0.7% [WWC] of their best performance for 200 m) at the 200-m mark compared with the lower-level athletes. Furthermore, the fatigue index was calculated as 22.99, 14.43, and 13.91% for the world-class, national, and regional levels, respectively. In summary, world-class runners adopt a more aggressive pacing strategy and demonstrate greater fatigue than the less experienced runners; this might indicate a greater mental commitment and/or a better capacity to run under fatigue.

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