title: The longer the better: Sleep-wake patterns during preparation of the World Rowing Junior Championships.
abstract: Recovery is essential for high athletic performance, and therefore especially sleep has been identified as a crucial source for physical and psychological well-being. However, due to early-morning trainings, which are general practice in many sports, athletes are likely to experience sleep restrictions. Therefore, this study investigated the sleep-wake patterns of 55 junior national rowers (17.7 ± 0.6 years) via sleep logs and actigraphy during a four-week training camp. Recovery and stress ratings were obtained every morning with the Short Recovery and Stress Scale on a 7-point Likert-type scale ranging from 0 (does not apply at all) to 6 (fully applies). The first training session was scheduled for 6:30 h every day. With two to four training sessions per day, the training load was considerably increased from athletes' home training. Objective sleep measures (n = 14) revealed less total sleep time (TST) in the first two weeks (409.6 ± 19.1 and 416.0 ± 16.3 min), while training volume and intensity were higher. In the second half of the camp, less training sessions were implemented, more afternoons were training free and TSTs were longer (436.3 ± 15.8 and 456.9 ± 25.7 min). A single occasion of 1.5-h delayed bedtime and usual early morning training (6:30 h) resulted in reduced ratings of Overall Recovery (OR) (M = 3.3 ± 1.3) and greater Negative Emotional State (NES) (M = 1.3 ± 1.2, p < .05), which returned to baseline on the next day. Following an extended night due to the only training-free day, sleep-offset times were shifted from ~5:30 to ~8:00 h, and each recovery and stress score improved (p < .01). Moreover, subjective ratings of the first six days were summarised as a baseline score to generate reference data as well as to explore the association between sleep and recovery. Intercorrelations of these sleep parameters emphasised the relationship between restful sleep and falling asleep quickly (r = .34, p < .05) as well as few awakenings (r = .35, p < .05). Overall, the findings highlight the impact of sleep on subjective recovery measures in the setting of a training camp. Providing the opportunity of extended sleep (and a day off) seems the most simple and effective strategy to enhance recovery and stress-related ratings.
authors.affiliation: a Ruhr University Bochum , Faculty of Sport Science , Bochum , Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Kölling
authors.affiliation: b University Medical Centre Ulm , Sports and Rehabilitation Medicine , Ulm , Germany.
authors.forename: Jürgen M
authors.initials: JM
authors.lastname: Steinacker
authors.affiliation: c Johannes Gutenberg University Mainz, Institute of Sport Science , Mainz , Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Endler
authors.affiliation: a Ruhr University Bochum , Faculty of Sport Science , Bochum , Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Ferrauti
authors.affiliation: d Saarland University , Institute of Sports and Preventive Medicine , Saarbruecken , Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Meyer
authors.affiliation: a Ruhr University Bochum , Faculty of Sport Science , Bochum , Germany.|e University of Queensland , School of Human Movement Studies and Nutrition Sciences , Brisbane , Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Kellmann
mesh_terms: D056044:Actigraphy / Q000379:methods; D000293:Adolescent; D056352:Athletes / Q000523:psychology*; D054874:Athletic Performance / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D005221:Fatigue; D005260:Female; D006801:Humans; D008297:Male; D012890:Sleep / Q000502:physiology*; D013177:Sports; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult
keywords: Athletes; recovery; sleep monitoring; stress; training