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

NCT ID: NCT06891469

Last Updated: 2025-03-26

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 12 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-01-22
• Study Completion Date: 2022-05-29

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.

Detailed Description

Preliminary measurements The preliminary measurements included anthropometry, body composition estimation, dietary and habitual caffeine consumption assessment. To assess habitual caffeine consumption, the volunteers were asked to answer a questionnaire through an interview, which investigated the typical consumption of specific caffeine-containing foods and beverages over the past month. Additionally, medical history information was collected through personal interviews.

Main tests Aerobic fitness and maximum heart rate were assessed using the 20-meter shuttle run at an indoor gymnasium. For each main session, the volunteers arrived at the gym having followed specific preparation instructions. Specifically, they were instructed to avoid intense exercise for 24 hours before the test, be hydrated, eat a carbohydrate-rich meal 3-4 hours earlier, avoid alcohol for 24 hours before the test, and refrain from energy drinks, supplements, or caffeine on the test day.

The two main tests were conducted at the same time of day and under similar environmental conditions for each volunteer. After being weighed, the volunteers took either caffeine or biotin capsules, and, 40 minutes later, they began warming up so that the training session would start 60 minutes after taking the supplement. Before the warm-up, blood lactate concentration was measured using the Lactate Scout 4 automatic lactate analyzer.

The volunteers executed five exercises (50 seconds on, 10 seconds off) for four rounds, aiming to perform as many repetitions as possible with the correct technique. The five exercises were push-ups, power cleans, front squats, sit-ups, and deadlifts. The power clean, front squat, and deadlift were performed with an external load of approximately 40%, 50%, and 60% of body weight, respectively.

Performance was defined as the total number of repetitions per round (i.e. the sum of repetitions in all exercises per round), as well as the number of repetitions performed in each exercise per round.

At the end of each round, the rating of perceived exertion (RPE) was recorded using the 6-to-20 Borg scale, and, one minute after the end of the workout, blood lactate concentration was measured again.

HR was monitored using a HR monitor (Polar H10) throughout the workout and averaged over each round.

Additionally, after completing the training sessions, the volunteers provided information about possible side effects (tachycardia, palpitations, feelings of anxiety/discomfort, headache, dizziness).

Conditions

Healthy, Young Adults; Athletic Performance

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: OTHER
• Blinding Strategy: TRIPLE

Study Groups

Caffeine

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)

Group Type: ACTIVE_COMPARATOR

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

Intervention Type: 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.

Placebo

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

Group Type: PLACEBO_COMPARATOR

Placebo (Biotin Capsules)

Intervention Type: DIETARY_SUPPLEMENT

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

Interventions

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

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.

Intervention Type: DIETARY_SUPPLEMENT

Placebo (Biotin Capsules)

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

Intervention Type: DIETARY_SUPPLEMENT

Eligibility Criteria

Inclusion Criteria

• 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

Exclusion Criteria

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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 40 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: No

Sponsors

Democritus University of Thrace

OTHER

Sponsor Role: lead

Responsible Party

ZOI KONIDARI

DIETICIAN-NUTRITIONIST

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

ILIAS SMILIOS, Professor

Role: STUDY_DIRECTOR

Democritus University of Thrace

VASSILIS MOUGIOS, Professor

Role: STUDY_DIRECTOR

Aristotle University Of Thessaloniki

GREGORY C. BOGDANIS, Professor

Role: STUDY_CHAIR

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

Locations

Stefanos Karalis Indoors Facilities

Athens, Byron, Greece

Countries

Greece

References

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

Reference Type: BACKGROUND

PMID: 30977054 (View on PubMed)

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.

Reference Type: BACKGROUND

PMID: 33388079 (View on PubMed)

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.

Reference Type: BACKGROUND

PMID: 29484512 (View on PubMed)

Study Documents

Document Type: Individual Participant Data Set

figshare

View Document

Related Links

https://doi.org/10.6084/m9.figshare.28426292

Full data set of measurement performed in the study

Other Identifiers

DPTH/EHDE/18605/118

Identifier Type: -

Identifier Source: org_study_id