Strategic Daytime Napping Enhances Agility and Lowers Perceived Exertion But Does Not Improve Fatigue Resistance in Adolescent Soccer Players

Background

Daytime napping is increasingly incorporated into athletic recovery routines to manage sleepiness and support alertness. However, the effects of different nap durations on high-intensity anaerobic performance tasks remain insufficiently characterized, particularly in team-sport settings. Nap duration and circadian timing may influence psychomotor readiness, perceived exertion, and fatigue-related responses, yet existing evidence is limited and inconsistent in adolescent athlete populations. This study is designed to examine the acute effects of two daytime nap durations within a controlled experimental framework.

Methods

This study will employ a randomized, crossover design involving sixteen competitive male adolescent soccer players classified as intermediate chronotypes. Each participant will complete three experimental conditions in a randomized order: no nap (N0), a 25-minute nap (N25), and a 45-minute nap (N45), with standardized washout periods between sessions. Nap compliance will be objectively monitored using wrist-worn actigraphy.

Following each condition, participants will observe a standardized 60-minute post-nap wakefulness period prior to performance testing. Agility performance will be assessed using the Pro Agility Test, and anaerobic endurance will be evaluated using a repeated-sprint ability (RSA) protocol. Psychophysiological measures will include ratings of perceived exertion (RPE), the Hooper Index, visual analogue scales (VAS) for subjective alertness, and mood states assessed via the Profile of Mood States (POMS). These outcomes will be collected to compare responses across nap conditions.

Objectives

The primary objective of this study is to compare the acute effects of two daytime nap durations (25 minutes vs 45 minutes) on agility performance in adolescent soccer players without a habitual napping routine. Secondary objectives include examining nap-related differences in repeated-sprint performance indices, perceived exertion, subjective alertness, and mood states.

Keywords

daytime nap; athletic recovery; agility; repeated-sprint ability; perceived exertion; mood; chronotype

Study Overview

• Status: Completed
• Conditions: Fatigue; Sleep Deprivation; Athletic Performance
• Intervention / Treatment: Behavioral: Pro Agility Test; Behavioral: Repeated-Sprint Ability (RSA) Test; Behavioral: Rate of Perceived Exertion (RPE)

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

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Malatya
    • Malatya, Malatya, Turkey (Türkiye), 44000
      • İnonu University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• being a member of the Yeni Malatyaspor U19 or U17 team
• having no history of illness or injury
• no regular napping habit

Exclusion Criteria:

• active infections
• hyperactivity
• sleep disorders
• sleep problems on protocol days

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: No Nap; No Nap Conditions	Behavioral: Pro Agility Test; The Pro Agility Test (20-yard shuttle run) evaluates change-of-direction speed. Participants started from the center point, ran 5 yards to the left, then 10 yards to the right, and finally 5 yards back to the center. The total distance was 18.28 meters, and the time to complete the sequence was recorded. Agility and RSA timings were recorded using a dual-beam electronic timing system (SmarTracks, Germany) with a sampling frequency of 1,000 Hz, positioned at the start and finish lines at hip level. This minimized human error and ensured millisecond precision.; Behavioral: Repeated-Sprint Ability (RSA) Test; The RSA test measures an athlete's ability to repeatedly produce maximal sprint efforts with limited recovery. This study employed 6 × 30-meter sprints with 20-second rest intervals between each sprint, a protocol commonly used in team sports to assess anaerobic endurance.; Behavioral: Rate of Perceived Exertion (RPE); RPE was assessed using the Borg Scale (6-20), which captures the participant's subjective effort during physical activity. RPE was recorded immediately after each sprint during the RSA Test, and the average RPE score represented overall perceived exertion for the session.
Experimental: 25 Min Nap; 25 Min Nap Conditions	Behavioral: Pro Agility Test; The Pro Agility Test (20-yard shuttle run) evaluates change-of-direction speed. Participants started from the center point, ran 5 yards to the left, then 10 yards to the right, and finally 5 yards back to the center. The total distance was 18.28 meters, and the time to complete the sequence was recorded. Agility and RSA timings were recorded using a dual-beam electronic timing system (SmarTracks, Germany) with a sampling frequency of 1,000 Hz, positioned at the start and finish lines at hip level. This minimized human error and ensured millisecond precision.; Behavioral: Repeated-Sprint Ability (RSA) Test; The RSA test measures an athlete's ability to repeatedly produce maximal sprint efforts with limited recovery. This study employed 6 × 30-meter sprints with 20-second rest intervals between each sprint, a protocol commonly used in team sports to assess anaerobic endurance.; Behavioral: Rate of Perceived Exertion (RPE); RPE was assessed using the Borg Scale (6-20), which captures the participant's subjective effort during physical activity. RPE was recorded immediately after each sprint during the RSA Test, and the average RPE score represented overall perceived exertion for the session.
Experimental: 45 Min Nap; 45 Min Nap Conditions	Behavioral: Pro Agility Test; The Pro Agility Test (20-yard shuttle run) evaluates change-of-direction speed. Participants started from the center point, ran 5 yards to the left, then 10 yards to the right, and finally 5 yards back to the center. The total distance was 18.28 meters, and the time to complete the sequence was recorded. Agility and RSA timings were recorded using a dual-beam electronic timing system (SmarTracks, Germany) with a sampling frequency of 1,000 Hz, positioned at the start and finish lines at hip level. This minimized human error and ensured millisecond precision.; Behavioral: Repeated-Sprint Ability (RSA) Test; The RSA test measures an athlete's ability to repeatedly produce maximal sprint efforts with limited recovery. This study employed 6 × 30-meter sprints with 20-second rest intervals between each sprint, a protocol commonly used in team sports to assess anaerobic endurance.; Behavioral: Rate of Perceived Exertion (RPE); RPE was assessed using the Borg Scale (6-20), which captures the participant's subjective effort during physical activity. RPE was recorded immediately after each sprint during the RSA Test, and the average RPE score represented overall perceived exertion for the session.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pro Agility Test	Change-of-direction performance assessed using the Pro Agility Test (20-yard shuttle run). Participants will complete the test following each experimental condition (no nap, 25-minute nap, and 45-minute nap). The total time to complete the test will be recorded in seconds using an electronic timing system.	Immediately after completion of each experimental condition, within a single testing session.
Best sprint (s)	Best sprint time measured during a repeated-sprint ability (RSA) test. Participants will perform a standardized RSA protocol consisting of repeated maximal sprints with fixed recovery intervals. The fastest single sprint time achieved during each RSA test will be recorded in seconds for each experimental condition (no nap, 25-minute nap, and 45-minute nap) using an electronic timing system.	During each experimental testing session, immediately following the nap or no-nap condition.
Total sprint (s)	Total sprint time measured during a repeated-sprint ability (RSA) test. Participants will perform a standardized RSA protocol consisting of repeated maximal sprints separated by fixed recovery intervals. Total sprint time will be calculated as the sum of all sprint times completed during the RSA test for each experimental condition (no nap, 25-minute nap, and 45-minute nap) and recorded in seconds using an electronic timing system.	During each experimental testing session, immediately following the nap or no-nap condition.
4. Rate of Perceived Exertipon (RPE)	Perceived exertion assessed using the Borg 6-20 Rating of Perceived Exertion (RPE) scale. Participants will report their perceived exertion immediately after each sprint during the repeated-sprint ability test. The mean RPE score for each testing session will be calculated for each experimental condition.	Immediately after completion of the repeated-sprint ability test in each experimental session.
Hooper Index	Subjective recovery status assessed using the Hooper Questionnaire. The questionnaire evaluates perceived fatigue, stress, muscle soreness, and sleep quality using standardized Likert-scale ratings. Participants will complete the Hooper Questionnaire following each experimental condition (no nap, 25-minute nap, and 45-minute nap), and a total Hooper Index score will be calculated for each session.	After completion of each experimental session, following the nap or no-nap condition.
Subjective Alertness (VAS)	Subjective alertness will be assessed using a visual analogue scale (VAS). Participants will rate their perceived level of alertness on a 100-mm horizontal line anchored by "extremely sleepy" at one end and "fully alert" at the other. VAS assessments will be completed following each experimental condition (no nap, 25-minute nap, and 45-minute nap), and the distance from the left anchor will be recorded in millimeters as the alertness score.	After completion of each experimental session, following the nap or no-nap condition.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pittsburgh Sleep Quality Index (PSQI)	Sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI). The PSQI is a validated self-report questionnaire consisting of 19 items that generate a global score ranging from 0 to 21, with higher scores indicating poorer subjective sleep quality. The PSQI will be administered once at baseline to characterize participants' habitual sleep quality prior to the experimental nap protocols.	At baseline, prior to the first experimental session.
Resting Heart Rate (HR)	Resting heart rate will be measured in beats per minute (bpm) under standardized resting conditions. Heart rate will be recorded following a seated rest period prior to the experimental procedures to provide a baseline physiological characteristic of the participants.	At baseline, prior to the first experimental session.
Profile of Mood States (POMS)	Mood states will be assessed using the Profile of Mood States (POMS) questionnaire. The POMS evaluates multiple dimensions of mood, including tension, depression, anger, vigor, fatigue, and confusion. Participants will complete the questionnaire under standardized conditions to characterize baseline psychological status prior to the nap interventions.	At baseline, prior to the first experimental session.

Collaborators and Investigators

• Sponsor: Uludag University
• Collaborators: Inonu University; Princess Nourah Bint Abdulrahman University
• Investigators: Study Chair: Mertkan Öncü, MsC, Uludag University; Principal Investigator: Monira I. Aldhahi, PhD, Nourah bint Abdulrahman University

Publications and helpful links

General Publications

• Eken O, Oncu M, Kurtoglu A, Bozkurt O, Turkmen M, Aldhahi MI. The Acute Effects of 25- Versus 60-Minute Naps on Agility and Vertical Jump Performance in Elite Youth Soccer Players: The Role of Individual Chronotype. Life (Basel). 2025 Mar 7;15(3):422. doi: 10.3390/life15030422.

Study record dates

Study Major Dates

• Study Start (Actual): May 10, 2024
• Primary Completion (Actual): May 18, 2024
• Study Completion (Actual): May 18, 2024

Study Registration Dates

• First Submitted: November 21, 2025
• First Submitted That Met QC Criteria: December 17, 2025
• First Posted (Estimated): January 2, 2026

Study Record Updates

• Last Update Posted (Estimated): January 2, 2026
• Last Update Submitted That Met QC Criteria: December 17, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Agility; Perceived Exertion; Chronotype; Mood State; Sleep Inertia; Daytime Napping; Repeated Sprint Ability
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Sleep Wake Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Disorders of Excessive Somnolence; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Fatigue; Sleep Deprivation; Idiopathic Hypersomnia
• Other Study ID Numbers: 2024/5635

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be shared. The study involves a small, homogeneous sample of adolescent athletes, and the dataset includes sensitive performance and psychophysiological measures. Sharing IPD could compromise participant confidentiality and was not included in the original informed consent.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No