Heavy Hitters, Light Sleepers: Collision Frequency and Locomotor Load on Sleep Architecture in Professional Rugby Union Players.

To assess whether certain players are more vulnerable to postmatch sleep disturbances by examining the relationship between match demands-collision frequency and locomotor load-and sleep in professional male rugby union players. A linear mixed-effects regression examined the relationship between match variables and sleep in 13 rugby players across three matches. Match variables included six physical demand variables derived from video analysis and GPS data (collision frequency, total distance, high-speed distance, sprint distance, acceleration load and fast acceleration count) and two contextual variables (location and kick-off time). Sleep variables collected via home-based polysomnography included total sleep time, sleep efficiency, sleep onset/offset, sleep onset latency, wake after sleep onset, number of awakenings and sleep stages (light, deep and rapid eye movement sleep [REM], evaluated both by proportion [%] and time [min]). Each match collision decreased total sleep time (β = -4 ± 1 min and p = 0.006) and REM sleep (time: β = -2 ± 0 min and p < 0.001; proportion: β = -0.6 ± 0.2% and p = 0.021). Conversely, every 500 m increase in locomotor load (total distance) increased REM sleep (time: β = +6 ± 2 min and p = 0.014; proportion: β = +2.7 ± 0.6% and p = 0.002). Every 100 m increase in high-speed distance was associated with decreased REM sleep time (β = -7 ± 3 min and p = 0.020). Match demands, including collision frequency and locomotor load, were associated with changes in postmatch sleep architecture in professional rugby players, particularly REM sleep. Furthermore, greater number of collisions was associated with reduced sleep quantity. Practitioners can leverage GPS and video analysis data to tailor additional sleep strategies aimed at improving postmatch sleep based on individual match demands.