The influence of training load and schedule on youth athletes' sleep.

Sleep is important for youth athletes, supporting sport-related recovery and performance, as well as growth and development. Sleep may be influenced by training factors; therefore, this study aimed to characterise youth athletes' sleep, and examine associations between training load, schedule and frequency, and sleep. Twenty-six youth basketballers (age: 14.22 ± 0.74 years, 13 male, 13 female) from a high-performance sporting school were monitored for a period of 8 weeks. Sleep measures (via actigraphy and sleep diaries) were collected alongside training diaries (recording time, duration and perceived exertion). Youth athletes who finished training after 20:30 hours had significantly less total sleep time than when training finished before 20:30 hours. Higher daily total training duration was associated with decreased total sleep time. There is a potential contradiction with findings related to the number of sessions per day, as participants who completed two training sessions in a day had more sleep than those who completed one session per day; but this was not observed for athletes with three sessions per day. Participants had large intra-individual variations (mean intra-individual standard deviation) in bedtime (1.06 hr) and sleep time (0.84 hr). In conclusion: (1) late night training sessions appear to reduce total sleep time and should be avoided in youth athletes; (2) total daily training duration had a greater negative effect on sleep than session frequency; and (3) participants' large intra-individual variation in bedtime may reduce sleep quality and efficiency.