INCREASED HOURS OF TRAINING PER WEEK IS ASSOCIATED WITH DECREASED SLEEP IN PEDIATRIC & ADOLESCENT ATHLETES
Authors: Milewski Matthew D. , McCracken Caitlin M. , Meehan Bill , Stracciolini Andrea 
Published: March 2019

BACKGROUND Sleep duration and sport specialization have been shown to affect injury profile in young athletes. The interplay between training hours per week, and, multiple versus single sports participation on sleep hours in young athletes is unknown. Purpose/Objective To investigate associations between single sport participation and training volume, with sleep hours, in pediatric and adolescent athletes. METHODS Study design: Cross-sectional epidemiological study was conducted using electronic questionnaire data from an injury prevention evaluation (IPE) at a sports injury prevention center affiliated with a tertiary level pediatric medical center between April 2013 and February 2018. Data analysis included sports participation, previous injury history, training regimen, and sleeping habits. For each sport selected, athletes were asked about average number of practice hours for each sport and number of seasons training for the sport during the year. All athletes aged 11-18 years were included in the study. Main outcome measures include sleep duration, single sport, and training hours/seasons. Single sport athletes were defined as those athletes who listed participation in only one sport year-round. Binary measures were created to indicate 1)any participant that listed practicing > 10 hour/week for any sport during a season and 2) any participant that trains three or more seasons for any sport in which they participate. Multivariate regression models (M1, M2, M3) were created for soccer athletes to control for sport training differences while testing the independent effect of gender, age and sport training. Based on the results univariate linear regression of hours of sleep was stratified by age and gender and regressed by self-reported hours of practice per week, identification as single sport athlete, training three or more seasons for soccer. RESULTS There were 756 athletes, 11-18 years old, included (mean age 13.5±2.5 years; 56% female (N=426)). For female athletes, figure skating (46%, 11/24), dance (42%, 28/67), and gymnastics (25%, 12/47) lead the list for single sport athletes. In comparison, for male athletes, swimming (26%, 5/19), tennis (19%, 5/26) and soccer (13%, 16/120) lead the list. The overwhelming majority of gymnasts, dancers, and figure skaters (88% (38/43), 83% (54/66) and 83%, (20/24)) train = 3 seasons of the year. In comparison, for male athletes, tennis athletes (62%, 16/25) seem to train = 3 seasons of the year followed by soccer (41%, 49/119) and swimming (39%, 7/18). (Tables 1 and 2) Table 3 presents multivariate linear regression coefficient of weeknight hours slept by practice hours, gender, age and sport characteristics for soccer participants using three different models (M1, M2, M3). Younger athletes, ages 11-14 years, slept nearly an hour more than participants aged 15-18 years across all training types. Only female soccer athletes training = 3 seasons slept significantly less (ß -0.24, SE 0.12, 95%) than their male counterparts. Participants that practiced soccer > 10 hours/week slept significantly, and substantively, less than their peers practicing =3 or less hours/week (ß -0.61, SE 0.17, 95%). Table 4 presents all participants and sport type stratified by age and sex. Practicing more than 10 hours/week was significant in males ages 11-14 years. Middle school aged males, practicing > 10 hours/week for any sport in which they participate over the course of the year, slept over half an hour less than their peers that practiced fewer hours (ß -0.65, SE 0.2, 95%). CONCLUSIONS/SIGNIFICANCE Training volume appears to affect sleep in young athletes. Middle school male athletes practicing greater than 10 hours/week appear to sleep less than their peers. Anticipatory guidance surrounding training may help to improve sleep hygiene in pediatric and adolescent athletes. [Table: see text][Table: see text][Table: see text][Table: see text]