]>
IRCT20241205063953N5 IRCT 2026-05-30 Islamic Azad University Effect of Time of Day on the Ergogenic Responses to Caffeine in Adolescent Futsal Players Time-of-Day Modulates Caffeine Ergogenicity in Adolescent Futsal Players: Effects on Repeated-Sprint Performance, Readiness, and Mood 2026-06-05 anticipated 24 Complete https://irct.ir/trial/90385 interventional Randomization: N/A, Blinding: Triple blinded, Placebo: Used, Assignment: Crossover, Purpose: Health service research, Blinding description: Caffeine and placebo capsules are identical in shape, color, size, appearance, and packaging. Caffeine is administered as anhydrous caffeine at 3 mg·kg⁻¹ body mass, and placebo capsules contain microcrystalline cellulose. Supplement preparation, coding, and packaging are performed by an independent person. Participants, coaches, outcome assessors, researchers present during testing, and data analysts remain blinded to supplement allocation until completion of analyses. After each experimental trial, participants’ guesses regarding supplement identity are recorded to evaluate blinding success. N/A The study was conducted in healthy adolescent athletes and aims to examine the acute effect of caffeine ingestion on sports performance, perceptual readiness, and mood during morning and evening testing. This is not a disease-focused trial.. Intervention 1: First intervention group: Morning caffeine. The participant receives anhydrous caffeine capsules at 3 mg·kg⁻¹ body mass with 250 mL water, 60 min before the morning testing session. Morning testing is performed between 08:00 and 09:00 h. Intervention 2: Second intervention group: : Morning placebo. The participant receives placebo capsules containing microcrystalline cellulose, visually identical to caffeine capsules, with 250 mL water, 60 min before the morning testing session. Morning testing is performed between 08:00 and 09:00 h. Intervention 3: Third intervention group: Evening caffeine. The participant receives anhydrous caffeine capsules at 3 mg·kg⁻¹ body mass with 250 mL water, 60 min before the evening testing session. Evening testing is performed between 17:00 and 18:00 h. Intervention 4: Fourth intervention group: Evening placebo. The participant receives placebo capsules containing microcrystalline cellulose, visually identical to caffeine capsules, with 250 mL water, 60 min before the evening testing session. Evening testing is performed between 17:00 and 18:00 h. Yes - There is a plan to make this available What will be shared: Performance, perceptual, mood, and safety data across morning caffeine, morning placebo, evening caffeine, and evening placebo conditions. after deidentification, data will include RSA indices, CMJ, sprint, agility, RPE, VAS, BRUMS, and adverse-symptom variables. When: From publication of the article for 6 months To whom: Academic and scientific researchers with a reasonable request and a clearly specified research purpose. Conditions: Data may be used only for scientific purposes, reanalysis, meta-analysis, or methodological review; commercial use or attempts to identify participants are not permitted. Where to obtain: From the corresponding author manager How to obtain: Requests should be submitted by email and include the research purpose, requested data, and planned analyses. After review and approval, data will be shared as a secure digital file. Estimated review time: 2–4 weeks. Comments:
public Akram Jafari
Islamic Azad University Shahrekord Branch, Rahmatieh
Shahrekord Iran (Islamic Republic of) 8818730003 +98 38 3361 0001 Jafari.akm@gmail.com Islamic Azad University scientific Akram Jafari
Islamic Azad University Shahrekord Branch, Rahmatieh
Shahrekord Iran (Islamic Republic of) 8818730003 0098383361001 Jafari.akm@gmail.com Islamic Azad University Iran (Islamic Republic of) Male adolescent futsal players aged 14–18 years At least 2 years of structured futsal training experience Participation in organized training at least 3 sessions per week Good general health and no musculoskeletal injury during the previous 3 months No diagnosed cardiovascular, metabolic, neurological, psychiatric, or sleep-related disorder 14 years 18 years Male Habitual consumption of caffeine greater than 3 milligrams per kilogram of body mass per day Known caffeine hypersensitivity or intolerance Z00.0 Encounter for general adult medical examination N/A N/A N/A N/A First intervention group: Morning caffeine. The participant receives anhydrous caffeine capsules at 3 mg·kg⁻¹ body mass with 250 mL water, 60 min before the morning testing session. Morning testing is performed between 08:00 and 09:00 h. Second intervention group: : Morning placebo. The participant receives placebo capsules containing microcrystalline cellulose, visually identical to caffeine capsules, with 250 mL water, 60 min before the morning testing session. Morning testing is performed between 08:00 and 09:00 h. Third intervention group: Evening caffeine. The participant receives anhydrous caffeine capsules at 3 mg·kg⁻¹ body mass with 250 mL water, 60 min before the evening testing session. Evening testing is performed between 17:00 and 18:00 h. Fourth intervention group: Evening placebo. The participant receives placebo capsules containing microcrystalline cellulose, visually identical to caffeine capsules, with 250 mL water, 60 min before the evening testing session. Evening testing is performed between 17:00 and 18:00 h. Repeated-sprint ability mean time. Timepoint: During each of the four experimental sessions, after caffeine or placebo ingestion and standardized warm-up. Method of measurement: Six maximal 20-m sprints interspersed with 20 s passive recovery; mean time across six sprints measured using electronic timing gates. Repeated-sprint ability total time. Timepoint: During each of the four experimental sessions, after caffeine or placebo ingestion and standardized warm-up. Method of measurement: Sum of times from six 20-m sprints in the RSA protocol. Best sprint time during the repeated-sprint. Timepoint: During each of the four experimental sessions, after caffeine or placebo ingestion and standardized warm-up. Method of measurement: Fastest time among six 20-m sprints measured using electronic timing gates. Percentage sprint decrement. Timepoint: During each of the four experimental sessions, after caffeine or placebo ingestion and standardized warm-up. Method of measurement: Calculated from sprint times obtained during the RSA protocol. Countermovement jump height. Timepoint: During each of the four experimental sessions, after caffeine or placebo ingestion and standardized warm-up. Method of measurement: Three maximal trials with hands on hips; the best jump height retained for analysis. 10-m and 20-m sprint times. Timepoint: During each of the four experimental sessions, after caffeine or placebo ingestion and standardized warm-up. Method of measurement: Two maximal trials from a standing start 0.5 m behind the first timing gate; fastest time measured using electronic timing gates. Illinois agility test. Timepoint: During each of the four experimental sessions, after caffeine or placebo ingestion and standardized warm-up. Method of measurement: Two maximal trials separated by 4 min passive recovery; best time retained for analysis. Rating of perceived exertion. Timepoint: During each of the four experimental sessions, after caffeine or placebo ingestion and standardized warm-up. Method of measurement: Borg scale. Mood indices. Timepoint: During each of the four experimental sessions, after caffeine or placebo ingestion and standardized warm-up. Method of measurement: Brunel Mood Scale scored according to published procedures. Islamic Azad University Approved 2023-11-11 Institutional Research Ethics Committee of Islamic Azad University, Shahrekord Branch Islamic Azad University Shahrekord Branch, Rahmatieh Shahrekord Chahar-Mahal-va-Bakhtiari Iran (Islamic Republic of)