This study assessed if scheduling (start time and day type) and workload variables influenced sleep markers (activity monitor) in professional academy footballers (n=11; 17.3±0.7yrs) over a 10-week in-season period. Separate linear mixed regressions were used to describe the effect of start time on the previous nights sleep, and the effect of day type (matchday, matchday+1) and workload on subsequent sleep. Workload variables were modelled by day (day), 7-day (acute), and 28-day (chronic) periods. Sleep duration following matchday+1 (400mins; 95%CI:368—432) was significantly reduced compared to all other day types (p<0.001). Sleep onset time following matchday (00:35; CI:00:04—01:12) and wake time on matchday+1 (09:00; CI:08:37—09:23) were also significantly later compared to all other day types (p<0.001). Sleep duration (19.1mins; CI:9.4–28.79), wake time (18mins; CI:9.3–26.6), and time in bed (16.8mins; CI:2.0–31.5) were significantly increased per hour delay in start time. When no activity was scheduled sleep duration (37mins; CI:18.1—55.9), sleep onset (42.1mins; CI:28.8–56.2), and wake times (86mins; CI:72–100) were significantly extended, relative to a 09:00 start time. Day, acute, and chronic workloads were associated with sleep onset and wake times only. Scheduled start times were associated with changes in sleep duration, therefore, delaying start times may increase sleep in this population
