Sleep restriction due to early morning training in adolescent competitive swimmers.
Conditions
Interventions
Group 1: Arm 1: Early morning first. Swimmers completed an 8-day training camp with morning training sessions starting at 07:00, followed by a second 8-day training camp with morning training sessions
Sponsors
Institut für Sport- und Präventivmedizin
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: Invited to national youth training camp by the German or Dutch swimming federation
Exclusion criteria
Exclusion criteria: Injury or medical condition that precludes physical exertion Clinically diagnosed sleep disorder
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Objective sleep duration, measured continuously using wrist-worn actigraphy (Actigraph BT-WGT3X ). Measured during four periods: two weeks before training camp 1, during training camp 1 (8 days), two weeks before training camp 2, and during training camp 2 (8 days). | — |
Secondary
| Measure | Time frame |
|---|---|
| Secondary outcomes: 1. Objective sleep parameters (bedtime, wake time, sleep onset latency, sleep efficiency): assessed every night during the two weeks preceding the training camp and throughout the training camp, measured using actigraphy (ActiGraph BT-WGT3X) in combination with a sleep diary. 2. Subjective sleep quality: assessed every night during the two weeks preceding the training camp and throughout the training camp, using a sleep diary. 3. Number and duration of daytime naps: assessed daily during the training camp (from day 3 onward), using a nap diary. 4. Perceived recovery and stress: assessed every morning during the two weeks preceding the training camp and throughout the training camp, using the Short Recovery and Stress Scale (SRSS; 8-item questionnaire). 5. Submaximal performance test (Lamberts & Lambert Submaximal Cycling Test, LSCT): heart rate (measured by palpation of the carotid artery), rate of perceived exertion (RPE; Borg Scale 6–20), stroke rate, and completion time (handheld stopwatch) at three intensity levels (60%, 80%, 90%), assessed before (day 1) and after the training camp (day 8). 6. Swimming performance over 100 m in each participant's main stroke and over 800 m freestyle: assessed before (day 1) and after the training camp (day 8), measured manually by experienced coaches using handheld stopwatches in a 50 m indoor pool. 7. Motivation: assessed using a visual analogue scale (VAS), before (day 1) and after the training camp (day 8). 8. Immunological response: measured through venous blood withdrawal on day 0, day 1, and day 8 before performance testing in the early and late conditions. Additionally, upper respiratory tract symptoms (Upper Respiratory Tract Infections, URTI) were recorded on day 1 and day 8 using a study-specific questionnaire (items: sore throat, hoarseness, runny nose, cough, repeated sneezing, fever, body aches, headache; symptom severity rated on a 3-point scale: mild/moderate/severe; additionally, impa | — |
Countries
Germany, Netherlands
Outcome results
None listed