Effects of an Acute Dose of Caffeine on the Performance of CrossFit Athletes

NCT06891469 | Completed

• 1 other identifier: DPTH/EHDE/18605/118
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial was to investigate the effect of an acute dose of caffeine on CrossFit performance in young, healthy male CrossFit athletes. The main questions it aimed to answer were whether an acute dose of caffeine, compared to placebo:

• Can improve performance in a specific CrossFit workout
• Leads to a reduction in the Rating of Perceived Exertion
• Leads to an increase in blood lactate concentration at the end of the workout Participants had to:
• Complete two sessions of a specific CrossFit training program (four rounds of five exercises, 50 seconds of exercise/10 seconds of rest), 60 minutes after consuming either anhydrous caffeine (7.1 ± 0.7 mg/kg of body mass) or an equivalent amount of placebo, aiming to perform as many repetitions as possible.
• Report subjective perception of fatigue using the Borg scale at the end of each round.

Conditions

Healthy, Young Adults; Athletic Performance

Keywords

caffeine; rating of perceived exertion; lactate; performance; high intensity functional training; CrossFit®

Outcome Measures

Primary Outcomes (3)

• Performance During CrossFit® Workout

  Performance was defined as the total number of repetitions completed by the volunteers in the CrossFit program, the repetitions of all exercises per round, and the repetitions of each specific exercise per round.

  After 5, 10, 15 and 20 minutes of exercise

• Rating of Perceived Exertion during the CrossFit program

  Each partictipant had to record the subjective perception of fatigue, using the Borg scale (6 to 20, with higher score meaning feeling of higher exertion), at the end of each round of CrossFit program

  during the last 10 s of the 5th, 10th, 15th and 20th minute of exercise

• Blood lactate concentration

  Blood lactate concentration was measured using the Lactate Scout 4 automatic lactate analyzer (EKF Diagnostics) in two time points: before the warm-up for CrossFit program and one minute after the end of the workout

  1st measurement before the warm up and 2nd measurement one minute after the end of workout (i.e. after 20 min of exercise)

Secondary Outcomes (3)

• Heart Rate

  Heart rate was measured every 1 second of exercise. For analysis, heart rate was averaged over the following time ranges: 1-5 , 6-10 , 11-15 and 16-20 minutes of exercise

• Aerobic fitness assessment

  baseline (during the 2nd visit)

• Maximum heart rate measurement

  Heart rate was continuously recorded during the test (every 1 s), until exhaustion. The highest heart rate at the time of exhaustion was recorded.

Study Arms (2)

Caffeine

ACTIVE COMPARATOR

Consumption of 7.1 ±0.7 mg/kg of body mass of anhydrous caffeine (Pure Caffeine tablets by Myprotein), 60 minutes before the start of the specific CrossFit training program (four rounds of five exercises, 50 seconds exercise/10 seconds rest)

Dietary Supplement: Caffeine administration according to body mass (moderate intake- 7 mg/kg)

Placebo

PLACEBO COMPARATOR

Consumption of biotin (BIOTIN tablets by Myprotein) as placebo, 60 minutes before the start of the specific CrossFit training program (four rounds of five exercises, 50 seconds exercise/10 seconds rest). The volunteers received the same number of capsules that they received in caffeine condition

Dietary Supplement: Placebo (Biotin Capsules)

Interventions

Caffeine administration according to body mass (moderate intake- 7 mg/kg) DIETARY_SUPPLEMENT

This randomized, double-blind, crossover study aimed to investigate the acute effects of caffeine consumption on physiological responses and performance during a strength-focused CrossFit workout. Participants will consume either anhydrous caffeine (7.1 ± 0.7 mg/kg of body mass) or placebo, 60 minutes before a CrossFit workout aiming to perform as many repetitions as possible.

Caffeine

Placebo (Biotin Capsules) DIETARY_SUPPLEMENT

Consumption of biotin (BIOTIN tablets by Myprotein) at the same time as caffeine.

Placebo

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Men
• Aged 18-40
• At least 2 years of experience with CrossFit programs
• Free of any medical condition that prevents the participant from performing the exercises of the training program at maximum capacity

You may not qualify if:

• Consumption of caffeine and guarana supplements, unless were discontinued for at least two weeks before participating in the study

Sponsors & Collaborators

• Democritus University of Thrace: lead

Study Sites (1)

Stefanos Karalis Indoors Facilities

Athens, Byron, 16231, Greece

Location

Related Publications (3)

• Pickering C, Grgic J. Caffeine and Exercise: What Next? Sports Med. 2019 Jul;49(7):1007-1030. doi: 10.1007/s40279-019-01101-0.

  PMID: 30977054 BACKGROUND

• Guest NS, VanDusseldorp TA, Nelson MT, Grgic J, Schoenfeld BJ, Jenkins NDM, Arent SM, Antonio J, Stout JR, Trexler ET, Smith-Ryan AE, Goldstein ER, Kalman DS, Campbell BI. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021 Jan 2;18(1):1. doi: 10.1186/s12970-020-00383-4.

  PMID: 33388079 BACKGROUND

• Claudino JG, Gabbett TJ, Bourgeois F, Souza HS, Miranda RC, Mezencio B, Soncin R, Cardoso Filho CA, Bottaro M, Hernandez AJ, Amadio AC, Serrao JC. CrossFit Overview: Systematic Review and Meta-analysis. Sports Med Open. 2018 Feb 26;4(1):11. doi: 10.1186/s40798-018-0124-5.

  PMID: 29484512 BACKGROUND

Related Links

• Full data set of measurement performed in the study

MeSH Terms

Interventions

Biotin

Intervention Hierarchy (Ancestors)

Imidazoles; Azoles; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Coenzymes; Enzymes and Coenzymes

Study Officials

• ILIAS SMILIOS, Professor

  Democritus University of Thrace

  STUDY DIRECTOR

• VASSILIS MOUGIOS, Professor

  Aristotle University Of Thessaloniki

  STUDY DIRECTOR

• GREGORY C. BOGDANIS, Professor

  Gregory C. Bogdanis National and Kapodistrian University of Athens, School of Physical Education and Sport Science

  STUDY CHAIR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: DIETICIAN-NUTRITIONIST

Study Record Dates

• First Submitted: March 4, 2025
• First Posted: March 24, 2025
• Study Start: January 22, 2022
• Primary Completion: May 29, 2022
• Study Completion: May 29, 2022
• Last Updated: March 26, 2025

Record last verified: 2025-03

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Access Criteria: The study diresctors, the study chair and those who will evaluate the article for publication

Locations

GR (1)