Middle and long distance athletics races viewed from the perspective of complexity

Middle and long distance athletics races behave as power-laws when time (or average speed) and distance are related, thus suggesting the presence of critical phenomena. Power-laws as a function of the athlete's position in the all-time world ranking allows us to define a Performance Index that reveals the existence of possible multifractal structures associated to the natural barriers to that the athletes tend in their evolution towards better results and in pursuit of world records. The new theories of self-organized critical phenomena provide an explanation for the power-law and fractal structures in systems at, or near, their critical points. In this paper we analyse the athletic races using these theories and as a result of this study a new variety of interpretations are posited.