During competition season, elite alpine skiers and ski jumpers occasionally travel to distant World Cup venues. This causes jet lag, which places an additional burden on winter sport athletes, as it can affect body function and sport performance. The purpose of this master's thesis was to determine the basic chronobiological characteristics of athletes from both sports disciplines, to further examine the recovery period after travel, and to provide recommendations for athletes, their coaches and support staff on how to manage this period.
In the first part of the study, in which we examined the basic chronobiological characteristics of elite winter sport athletes, 25 subjects of both genders were included (age 24.56 ± 4.13 years, body height 173.44 ± 9.03 cm and body weight 68.83 ± 15.28 kg). They completed the Morningness-Eveningness Questionnaire and the Epworth Sleepiness Scale only once during season at any time. In the second part, in which we examined time period of recovery after travel, eight subjects of both genders from both sports were included (age 24.38 ± 4.24 years, body height 170.13 ± 7.32 cm and body weight 64.25 ± 19.61 kg). Following a predetermined 10-day protocol, the subjects completed Liverpool Jetlag Questionnaire, Epworth Sleepiness Scale and Morningness-Eveningness Questionnaire. On average, the subjects crossed seven time zones.
The data analysis showed that the intermediate type was the most common among the test subjects, and that most subjects experienced lower to higher normal daytime sleepiness during the day. Additionally, there were no differences in daytime sleepiness between the chronotypes. Furthermore, the analysis showed there were statistically significant differences between days in the ratings of daytime sleepiness, perceived jet lag and ease of falling asleep. In other subscales, there were no statistically significant effects of day, part of the day, nor the interaction of measurement day and part of the day.
The results show the majority of the examined population identifies with morning and intermediate types, daytime sleepiness is within normal range, and there are no differences in daytime sleepiness between different chronotypes. Elite winter sport athletes are affected by jet lag to some extent, but in general the effect on them is not significant. Generalisation from sample to population is questionable in the second part of the study due to the small sample size. Therefore, further studies on larger number of subjects are needed, which will also result in more accurate recommendations for athletes during the period after travel.
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