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.

Study Overview

• Status: Completed
• Conditions: Sleep Restriction
• Intervention / Treatment: Behavioral: Sleep restriction

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Portugal
  • Porto, Portugal, 4200-450
    • Faculty of Sport, University of Porto

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: Yes

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Sleep restriction; During the intervention period (i.e., 9 consecutive days), the intervention group started the sleep protocol, sleeping only the quantity of hours defined for their individual chronic partial sleep restriction (15% of usual daily sleep hours). The amount and quality of sleep obtained were daily monitored through actigraphy devices, and all the players filled in a sleep diary when they woke up. During this period, players performed the SSGs in two different moments (moment 1 and moment 2), interspersed by 4 days.	Behavioral: Sleep restriction; During the intervention period (i.e., 9 consecutive days), the intervention group started the sleep protocol, sleeping only the quantity of hours defined for their individual chronic partial sleep restriction (15% of the usual sleep time). The amount and quality of sleep obtained were daily monitored through actigraphy devices, and all the players filled in a sleep diary when they woke up. During this period, players performed the SSGs in two different moments (moment 1 and moment 2), interspersed by 4 days.
No Intervention: Controls; Same intervention (i.e., soccer training and tests) as the other arm, but with no sleep restriction.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Game Performance Assessment Instrument (GPAI)	According to study purposes, tactical performance was defined as the main variables. Tactical analysis was performed using the Game Performance Assessment Instrument (GPAI), a tool designed to evaluate the individual tactical behavior (Memmert & Harvey, 2008; Oslin, Mitchell, & Griffin, 1998). It consists of seven components, two of which are evaluated when the player has the ball and the remaining five when the player does not have the ball possession. For example, decisions made about what to do with the ball during the game, and motor skill execution were classified as appropriate/efficient or inappropriate/inefficient. The main index proposed by Oslin et al. (1998) was calculated: Game Performance (GP). Based on actions deemed appropriate or inappropriate, the final score can range from 0 to 100%, with higher values denoting better outcomes.	Applied once in week 1 and once again in week 2

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sleep efficiency	The objective sleep data was collected using three axial accelerometers (ActiGraph LLC wGT3X-BT, Pensacola, USA) placed on the non-dominant wrist. To analyze the wrist actigraphy data, the ActiLife LLC Pro software (v6.13.3, Pensacola, USA) was used with a sampling frequency of 50Hz and an epoch of activity counts of 60s. Sleep efficiency (SE, percentage of time in bed that was spent asleep; CV=7%) was determined using the Sadeh's algorithm.	Collected daily during the two weeks of the intervention

Collaborators and Investigators

• Sponsor: José Afonso Coelho Neves

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2023
• Primary Completion (Actual): May 31, 2023
• Study Completion (Actual): December 31, 2023

Study Registration Dates

• First Submitted: March 23, 2025
• First Submitted That Met QC Criteria: March 28, 2025
• First Posted (Actual): April 4, 2025

Study Record Updates

• Last Update Posted (Actual): April 4, 2025
• Last Update Submitted That Met QC Criteria: March 28, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Keywords: soccer; performance; small-sided games; sleep restriction; tactical
• Other Study ID Numbers: CEFADE 9 2023

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Sensitive data belonging to a club, so we only had permission to report the statistical treatment, but not sharing the IPD.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No