Impaired Sleep Mediates the Negative Effects of Training Load on Subjective Well-Being in Female Youth Athletes:

Background:Although increased training load (TL) and impaired sleep are associated with decreases in subjective well-being in adult athletes, these relationships among female youth athletes are unclear. It is unknown whether the effects of sleep and TL on well-being are independent or whether alterations in sleep mediate the effects of TL on subjective well-being.Hypothesis:Sleep and TL exert independent effects on subjective well-being among youth athletes, although alterations in sleep mediate a significant portion of the effect of TL on well-being in female youth athletes.Study Design:Prospective cohort study.Level of Evidence:Level 4.Methods:A total of 65 female soccer athletes (age range, 13-18 years) were monitored for 1 year. Daily TL was determined by session rating of perceived exertion and converted to z-scores. Every morning, participants recorded sleep duration in hours and rated stress, mood, fatigue, and soreness on a scale from −3 to +3 (worst to best). Linear mixed-effects models and media...