Discussion
fatigue, napping, muscle soreness, alertness, sleepiness
The aim of the current study was to examine the effects of a short daytime nap following morning training on afternoon performance in a cohort of professional rugby union athletes. Utilizing a daytime nap of less than 1 hour (average of ~35 minutes) improved afternoon peak 6-second cycling power, lowered afternoon perception of exertion during exercise, and improved afternoon levels of fatigue and general muscle soreness. Therefore, a short daytime nap following morning training may support aspects of physical and perceptual recovery in the afternoon amongst professional rugby athletes and may be a useful strategy to implement in these settings.While this study is the first to evaluate the effects of a daytime nap on afternoon performance in professional rugby athletes, previous research has evaluated the effects of short daytime naps on physical performance in other cohorts. O’Donnell et al. [An additional benefit of daytime naps previously reported is that naps may reduce the perception of effort during exercise. Blanchfield et al. [Measures of fatigue, sleepiness, and alertness have been reported to improve after a daytime nap [One possible explanation for the current findings of fatigue and general muscle soreness may be linked to levels of cytokines such as interleukin-6 (IL-6) following the nap. Increased levels of IL-6 have been observed following physical exercise [No differences were observed between conditions for reaction time or Self-reported alertness. The lack of change in alertness and reaction time is contrary to previous results by Daaloul et al. [Given the applied nature of the present study and the difficulty of conducting research on professional athletes, it must be noted that within the current investigation complete case analysis was able to be conducted on 15 athletes meaning that all 15 athletes who started to study completed both conditions which is a strength of the investigation. However, there are several limitations that we must acknowledge within the current investigation. The nap duration and confirmation of being able to nap during the 1 hour were self-reported by athletes, which relied on athletes to assess whether they actually fell asleep, and we were unable to confirm napping via polysomnography (PSG) or any other objective measures. We felt that PSG was not a practically viable option in this setting, as it would take too long to set up in an already short timeframe. We also felt that it would be too unnatural and uncomfortable to use during a relatively short napping period. Alternatively, we considered the use of actigraphy, however, this method has been shown to have some issues in detecting naps in populations where sleep periods contain significant movement [