Effects of Afternoon Napping, Caffeine, and Standardised Active Recovery on Evening Athletic Performance

NCT07652424 | Completed

• 1 other identifier: ISSEPS-NAP-CAF-REC-2025
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

This study evaluated whether afternoon napping, caffeine ingestion, and a standardised active recovery and nutritional protocol could influence evening physical and cognitive performance in healthy university athletes. Participants completed five experimental conditions in a randomised crossover design: placebo without napping, napping with placebo, caffeine without napping, napping combined with caffeine, and napping combined with caffeine plus a standardised active recovery and nutritional protocol. The nap opportunity lasted 90 minutes and caffeine was administered at 5 mg/kg body mass. The main outcome was repeated agility performance. Additional outcomes included sprint performance, jumping performance, reaction time, subjective sleepiness, sleep characteristics during the nap opportunity, and selected physiological measures. The study also explored whether responses differed according to sex and chronotype.

Conditions

Athletic Performance; Sports Performance; Exercise Performance; Circadian Rhythm

Keywords

Napping; Caffeine; Recovery Protocol; Chronotype; Sex Differences; Evening Performance; Crossover Trial; Randomised Controlled Trial; Brain-Derived Neurotrophic Factor; Heart Rate Variability; Reaction Time; Agility; Jump Performance

Outcome Measures

Primary Outcomes (1)

• Repeated Modified Agility Test (RMAT) Total Time

  Total time (seconds) to complete 10 maximal 20-m sprints with four changes of direction (forward sprint, left shuffle, right shuffle, backward sprint). The test was conducted on an indoor hardwood court using dual-beam photocells (Brower Timing Systems, Salt Lake City, UT, USA) placed at the start/finish line. Participants started from a standing position 0.5 m behind the first photocell. Lower values indicate better repeated agility performance. This was the primary outcome measure used for sample size calculation.

  At approximately 19:35 on each of the five experimental days

Secondary Outcomes (10)

• Countermovement Jump (CMJ) Height

  At approximately 19:20 on each of the five experimental days.

• Squat Jump (SJ) Height

  At approximately 19:25 on each of the five experimental days.

• 20-m Sprint Time

  At approximately 19:45 on each of the five experimental days.

• Simple Reaction Time (SRT)

  At approximately 19:15 on each of the five experimental days.

• Choice Reaction Time (CRT)

  At approximately 19:20 on each of the five experimental days.

Study Arms (5)

PLA

PLACEBO COMPARATOR

Placebo capsule (microcrystalline cellulose) at 18:00, no nap opportunity

Other: Placebo

NAP

EXPERIMENTAL

90-minute afternoon nap opportunity (13:00-14:30) with objective sleep architecture recording via portable EEG headband (Dreem 3), followed by placebo capsule (microcrystalline cellulose) at 18:00. Participants remained in a quiet, dimly lit room during the nap opportunity.

Behavioral: Afternoon Nap; Other: Placebo

CAF

EXPERIMENTAL

Caffeine ingestion (5 mg/kg body mass of anhydrous caffeine) at 18:00, no nap opportunity. Participants remained in a quiet, dimly lit room during the 13:00-14:30 period.

Dietary Supplement: Caffeine

NAP+CAF

EXPERIMENTAL

90-minute afternoon nap opportunity (13:00-14:30) with EEG recording, followed by caffeine ingestion (5 mg/kg) at 18:00.

Behavioral: Afternoon Nap; Dietary Supplement: Caffeine

NAP+CAF+REC

EXPERIMENTAL

90-min afternoon nap opportunity (13:00-14:30) with portable EEG monitoring, caffeine ingestion (5 mg/kg body mass) at 18:00, and a 15-min standardised active recovery and nutritional protocol from 18:45 to 19:00. The protocol included lower-limb dynamic stretching followed by a carbohydrate-protein snack containing 20 g maltodextrin and 10 g whey isolate.

Behavioral: Afternoon Nap; Dietary Supplement: Caffeine; Combination Product: Standardised Active Recovery and Nutritional Protocol

Interventions

Standardised Active Recovery and Nutritional Protocol COMBINATION_PRODUCT

A 15-min standardised active recovery and nutritional protocol performed from 18:45 to 19:00. It included lower-limb dynamic stretching exercises (forward/backward and lateral leg swings, walking lunges, high knees, and butt kicks; 10 repetitions per leg at a controlled pace), followed by ingestion of a carbohydrate-protein snack containing 20 g maltodextrin and 10 g whey isolate mixed with 200 mL water.

NAP+CAF+REC

Afternoon Nap BEHAVIORAL

A 90-min afternoon nap opportunity from 13:00 to 14:30 in a quiet, dimly lit, temperature-controlled room. Sleep was monitored using a portable EEG headband. Participants were provided with earplugs and eye masks, and nap sleep characteristics, including sleep stages, were recorded.

NAP; NAP+CAF; NAP+CAF+REC

Caffeine DIETARY_SUPPLEMENT

Anhydrous caffeine (5 mg/kg body mass) was administered orally in an opaque capsule at 18:00. Placebo capsules contained microcrystalline cellulose and were matched for appearance, mass, colour, and odour. Capsule allocation was blinded to participants and outcome assessors.

CAF; NAP+CAF; NAP+CAF+REC

Placebo OTHER

Microcrystalline cellulose was administered orally in an opaque capsule at 18:00. Placebo capsules were matched to caffeine capsules for appearance, mass, colour, and odour.

NAP; PLA

Eligibility Criteria

• Age: 18 Years - 25 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy university athletes aged 18-25 years.
• Regular engagement in structured training, defined as at least 10 training sessions per week of approximately 2 h each, across team sports, judo, athletics, tennis, or swimming.
• Non-habitual napping, defined as fewer than one nap per week.
• Low habitual caffeine intake, defined as \<80 mg/day, assessed using a 7-day dietary recall.
• Non-smoker and free from regular medication or recreational drug use.
• No musculoskeletal injury during the preceding month.
• Good self-reported sleep quality, defined as a Pittsburgh Sleep Quality Index score \<5.
• Definite morning chronotype (MEQ score 59-86) or definite evening chronotype (MEQ score 16-41).
• For female participants: self-reported regular menstrual cycles (26-32 days), no hormonal contraceptive use, and no self-reported history of menstrual disorders.

You may not qualify if:

• Intermediate chronotype (MEQ score 42-58).
• Habitual napping (≥1 nap per week).
• Habitual caffeine intake ≥80 mg/day.
• Smoking, regular medication use, or recreational drug use.
• Musculoskeletal injury during the preceding month.
• Pittsburgh Sleep Quality Index score ≥5.
• Self-reported irregular menstrual cycles, hormonal contraceptive use, or history of menstrual disorders in female participants.
• Self-reported sleep disorder.
• Inability or unwillingness to complete all five experimental conditions.

Sponsors & Collaborators

• The Higher Institute of Sport and Physical Education of Sfax: lead

Study Sites (1)

Higher Institute of Sport and Physical Education of Sfax (ISSEP Sfax)

Sfax, 3000, Tunisia

Location

Related Links

• Open Science Framework - Data Repository

MeSH Terms

Interventions

Caffeine

Intervention Hierarchy (Ancestors)

Xanthines; Alkaloids; Heterocyclic Compounds; Purinones; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Officials

• Kais El Abed, Phd

  University of Sfax, Tunisia

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Double-blind, placebo-controlled design. Participants and investigators conducting the testing battery are blinded to condition assignment. The researcher preparing the capsules and the statistician are separate from the testing team. Blinding is maintained until final data analysis.
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: Randomised, counterbalanced crossover design with 5 experimental conditions. Each participant completes all conditions in a different order determined by Latin square randomisation. Washout period between conditions: at least 72 hours.

Study Record Dates

• First Submitted: June 10, 2026
• First Posted: June 17, 2026
• Study Start: January 2, 2025
• Primary Completion: May 31, 2025
• Study Completion: May 31, 2025
• Last Updated: June 30, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, ANALYTIC CODE
• Time Frame: IPD and supporting information are currently available on the Open Science Framework (OSF) repository at https://osf.io/3wq5j/. The dataset includes anonymised individual participant data (n=60, 300 experimental sessions), the R statistical analysis script, and the ethical approval certificate. Data will remain accessible indefinitely. Upon publication of the study results in a peer-reviewed journal, additional supporting documents (study protocol, statistical analysis plan, and informed consent form) will be added to the repository.
• Access Criteria: The anonymised IPD and supporting documents will be openly accessible to any researcher, clinician, or member of the public without restriction. No formal request process or approval is required. Users may download the data directly from the Open Science Framework (OSF) repository once deposited. Researchers who reuse the data are requested to cite the original publication and the OSF dataset DOI. The data are provided "as is" without any warranty or guarantee of accuracy.

Locations

TU (1)