Commentaries on Viewpoint: Resistance training and exercise tolerance during high-intensity exercise: moving beyond just running economy and muscle strength.

TO THE EDITOR: A consistent increase in endurance performance has often been observed after resistance training (RT) (4). Based on the critical power (CP) concept, Denadai and Greco (1) recently proposed an interesting model to explain this RT-induced improvement in endurance performance. According to these authors, the gains (35– 60%) in the curvature constant of the power-duration hyperbola (W=) could explain the performance improvements during constant-workload exercises performed above the CP after a RT program. However, it is important to highlight that during most athletic events, the intensity of the exercise is not previously fixed, but self-selected by the athletes. The intensity distribution during middleand long-distance running races has often been characterized by a U-shaped pacing profile, with start and finish intensities being higher than in the middle part of the race (5). This U-shaped pacing makes the W= use more complex, because athletes might switch from one exercise intensity domain to another throughout the race (3). This could indicate that the increase in W= with RT might be more relevant for some specific parts of the race, in which athletes perform at intensities above the CP, such as during the fast start and the final sprint. This suggestion is in agreement with previous findings showing that RT can counteract fatigue during the last part of a running race (2). Therefore, further research in this exciting area is necessary to elucidate the influence of RT on W= and its possible relationship with changes in specific parts of self-paced, real races.