Acute effect of an intensified exercise program on subsequent sleep, dietary intake, and performance in junior rugby players
The effect of exercise on sleep remains controversial in athletes especially in junior athletes. This study tested the acute effect of additional intense rugby training on sleep, next-day dietary intake, and physical performances in adolescent rugby players compared to a day with regular exercise. 17 male rugby players in the national under-17 category (age: 15.7 ± 1.1 years, height: 1.78 ± 0.1 m, weight: 84.4 ± 13.6 kg, BMI: 26.6 ± 3.8 kg/m2, fat mass: 14.5 ± 3.4%, VO2max Yo-Yo test: 52.1 ± 4.4 mL/min/kg, evening chronotype) took part in this study. The athletes completed two 36-h experimental sessions in random order: a regular exercise program (REP) vs. an intensified exercise program (IEP) at a 1-week interval. Physical activity and sleep data were collected using accelerometers. Performance tests were conducted the next morning after an ad libitum breakfast. Sleep improved during intensive training (TST: + 26 min, SL: − 4%, WASO: − 39%, SE: + 8.5%) with moderate effect size. There was no next-day difference in calorie intake from breakfast, but macronutrient composition shifted toward proteins (regular: 15.4 ± 6.1% vs. intensive: 18.9 ± 7.4%, ES = − 0.650 [− 1.13; − 0.18]). There were no significant differences in Wingate test performance or spatial awareness task time. However, performance in submaximal tests improved. Acute intensified training results in increased sleep duration and quality without disturbing next-day performance or dietary intake in young rugby players.
KeywordsSleep Adolescent Athlete Physical performances Nutritional behavior
Epworth sleepiness scale
Intensified exercise program
Horne–Östberg morningness–eveningness questionnaire
Pittsburgh sleep quality index
Regular exercise program
Total sleep time
Total time in bed
Wake after sleep onset
- Yo-Yo IR1
Yo-Yo intermittent recovery test level 1
We thank all the parents and junior elite athletes who took part in the study, and S. Rousset for technical assistance.
All authors made substantive contributions to the present study and were involved in writing, revision and had approved the final manuscript. OS and PD drafted the initial manuscript and approved the final manuscript as submitted. No payment was given. PD critically reviewed the manuscript and approved the final manuscript as submitted and take full responsibility for the manuscript. ED, DMI, FM and SW performed experimental assessments and data acquisition. OS, PD and BP made statistical analysis. There are no prior publications or submissions with any overlapping information. We attest that this work is original and has not been published elsewhere nor is it currently under consideration for publication elsewhere. No author has any potential conflict of interests to disclose.
No external funding was received for this work.
Compliance with ethical standards
Conflict of interest
The authors report no conflict of interest.
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