The Effects of Individualised Short-term Sleep Restriction on Tactical Performance

Influence Of Individualized Two Weeks Mild Sleep Restriction On Tactical Performance During Small-Sided Games In National Male Under-19 Football Players: A Randomized Trial

The goal was to evaluate the influence that chronic sleep restriction may have on football players tactical performance during small-sided games. By using a relative sleep restriction (i.e., by reducing the normal sleep duration by 15%) instead of an absolute sleep restriction (e.g., 3-4 hours), different sleep schedules were applied, according to the players individual sleep profile. It was hypothesized that the player's performance would be impaired, particularly their tactical behaviors when performing a 4x4 small-sided game format.

An impairment on cognitive and physical performance is commonly suggested in literature. However, there is a lack of information regarding sport-specific parameters. Thus, the present study aimed to examine whether chronic sleep restriction during 9 consecutive days impairs the tactical performance of football players during small-sided games (SSGs). A total of sixteen national level male football players wore wrist actigraphy units during night sleep throughout the study. Players were randomized into two groups: intervention (IG), and control (CG). The first four days corresponded to a familiarization period, where players were informed about the study procedures and started using wrist actigraphy. Throughout the next seven consecutive days, the characterization phase of sleep players profile (i.e., baseline) was collected and analyzed. Then, players entered the intervention phase, where the IG slept 15% less than routine. During this 9-days period, players performed a 4x4 SSGs in two moments (moment 1 and moment 2) with a week interval. The SSGs were recorded using a video camera and subsequently analyzed using the Game Performance Assessment Instrument.

Inclusion Criteria:

• Soccer players classified as Tier 3, corresponding to the National Level in accordance to McKay et al. (2022), as they represented the under-19 team playing in the Portuguese National Championship 1st Division.

Exclusion Criteria:

• 1) players with previously identified sleep disorders;
• 2) players with injuries that prevented them from playing SSGs.