The impact of sleep behaviours, chronotype and time of match on the internal and external outcomes of a tennis match

Tennis match performance is often evaluated by a player's internal (heart rate) and external (match analytics) outcomes. Numerous factors could influence these outcomes, including the time of day, which may be advantageous or not depending on a player's chronotype. This study aimed to determine the influence time of day, chronotype and sleep-wake behaviour (SWB) had on internal and external outcomes of tennis matches. Twelve state-level male tennis players, with a mean age of 28 +/- 7, stature of 183 +/- 7 and body mass of 86.6 +/- 17.4 wore an actigraph device and completed a sleep diary for the study duration. Based on rankings, players were paired against the same opponent and completed three tennis matches at 8:00 am, 2:00 pm and 8:00 pm, separated by a minimum of 48 h. Fatigue and chronotype, measured by the Fatigue Severity Scale, Morningness Eveningness Questionnaire and midsleep time, were assessed before matches; motivation, measured by the Intrinsic Motivation Inventory, was assessed after matches. During matches, players wore global positioning systems and heart rate monitors; the match analytics and players' rate of perceived exertion were recorded. Increased unforced errors and decreased winners and forced errors were observed in the evening matches. Decreased total distance and rate of perceived exertion during the second set were found for the evening compared to morning and afternoon matches. Chronotype and sleep-wake behaviour had trivial to weak associations with internal and external outcomes. These results indicate that players and coaches should consider the match times when training for future tournaments.