Abstract
Objectives: To test whether short-term sleep extension affects sleep, mood, and swim performance in adolescent competitive swimmers under real-world training. Methods: A pragmatic within-group, two-period crossover compared Regular and Extended sleep during routine in-season training. Outcomes included device-based sleep (with HRV-derived staging), pool performance (50-m sprint; mean 10×50-m pace; 800-m time trial), post-set physiology, and mood (EFI). Primary inference focused on the within-subject Regular vs Extended contrast; three-phase (Preliminary/Regular/Extended) ANOVAs were descriptive. Results: Total sleep time increased with Extended vs Regular, confirming successful manipulation. Group-level pool performance did not improve across tests (all paired contrasts non-significant). Mood changes were small and non-significant. Physiological responses were largely unchanged; however, post-set blood lactate after the 10×50-m set was modestly lower with Extended (Holm-adjusted p = .035). Sleep architecture shifted: Deep sleep was lower and arousal indices higher under Extended. Conclusions: In adolescent swimmers, short-term sleep extension is feasible and increases sleep duration under real-world conditions but does not yield immediate gains in pool performance. A small reduction in post-set lactate and alterations in sleep architecture warrant cautious interpretation. Findings temper expectations for near-term performance benefits and motivate longer, individualized protocols with monitoring of achieved extension dose.
Keywords
Sleep Extension, Adolescent Athletes, Swimming Performance, Sleep Architecture, Mood, Crossover Design,References
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