Healthy, Young AdultsNCT06891469
Effects of an Acute Dose of Caffeine on the Performance of CrossFit Athletes
A study testing Caffeine administration according to body mass (moderate intake- 7 mg/kg) in people with Healthy, Young Adults and Athletic Performance, run by Democritus University of Thrace at 1 site in Greece.
Trial 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… Read more about this study
- Who is it for?
- Ages 18 to 40 years, men only
- Conditions the study is for
- Healthy, Young Adults, Athletic Performance
- What is being tested?
- Caffeine administration according to body mass (moderate intake- 7 mg/kg)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 12 participants
- Where
- 1 siteGreece
- Study dates
- 22 Jan 2022to 29 May 2022
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- Men only
- No healthy volunteers
- Adult
Who may be able to join
- 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
Who cannot join
- Consumption of caffeine and guarana supplements, unless were discontinued for at least two weeks before participating in the study
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effects of an Acute High Dose of Caffeine on Physiological Responses and Performance During a Strength-Focused CrossFit® Workout: a Randomized, Double - Blinded, Crossover Study
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
Read more
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.
Read the 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
- Being tested
- Caffeine administration according to body mass (moderate intake- 7 mg/kg), Placebo (Biotin Capsules)
- Keywords
- caffeine, rating of perceived exertion, lactate, performance, high intensity functional training, CrossFit®
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
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.
Placebo (Biotin Capsules)Dietary supplement
Consumption of biotin (BIOTIN tablets by Myprotein) at the same time as caffeine.
| Study group | Role | What they receive |
|---|---|---|
| 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) Receives: 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 Receives: Dietary Supplement: Placebo (Biotin Capsules) |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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
Measured: 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
Measured: 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
Throughout the workout, heart rate was monitored using a heart rate monitor (Polar H10)
Measured: 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
Maximum oxygen consumption was estimated using the 20-meter shuttle run test from the number of shuttles completed at exhaustion.
Measured: baseline (during the 2nd visit)
Maximum heart rate measurement
Maximum Heart rate was determined during the 20-meter shuttle run test. Heart rate was continuously recorded using a heart rate monitor (Polar H10).
Measured: Heart rate was continuously recorded during the test (every 1 s), until exhaustion. The highest heart rate at the time of exhaustion was recorded.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Mar 2025
- Study start22 Jan 2022
- Primary completion29 May 2022
- Study completion29 May 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Healthy, Young AdultsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 12 participants (actual)
Sponsor and investigators
- Lead sponsor
- Democritus University of Thrace
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, ZOI KONIDARI, Democritus University of Thrace
- Investigators
- ILIAS SMILIOS, Professor, Study director, Democritus University of ThraceVASSILIS MOUGIOS, Professor, Study director, Aristotle University Of ThessalonikiGREGORY C. BOGDANIS, Professor, Study chair, Gregory C. Bogdanis National and Kapodistrian University of Athens, School of Physical Education and Sport Science
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06891469
- Sponsor's protocol ID
- DPTH/EHDE/18605/118
- Status last verified
- Mar 2025
- First submitted
- 4 Mar 2025
- Last updated
- 26 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All IPD that underlie results in a publication
Publications
Pickering C, Grgic J. Caffeine and Exercise: What Next? Sports Med. 2019 Jul;49(7):1007-1030. doi: 10.1007/s40279-019-01101-0.
PubMed 30977054Guest 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.
PubMed 33388079Claudino 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.
PubMed 29484512
Study at a glance
From the registry record, last updated by the sponsor on 26 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of an Acute High Dose of Caffeine on Physiological Responses and Performance During a Strength-Focused CrossFit® Workout: a Randomized, Double - Blinded, Crossover Study
- ClinicalTrials.gov ID
- NCT06891469
- Acronym / sponsor ID
- DPTH/EHDE/18605/118
- Conditions
- Healthy, Young Adults, Athletic Performance
- Keywords
- caffeine, rating of perceived exertion, lactate, performance, high intensity functional training, CrossFit®
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 12 participants (actual)
- Lead sponsor
- Democritus University of ThraceUniversity, hospital or other
- Study start
- 22 Jan 2022 (actual)
- Primary completion
- 29 May 2022 (actual)
- Study completion
- 29 May 2022 (actual)
- First posted
- 24 Mar 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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).
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Caffeine | Active comparator | Dietary Supplement: Caffeine administration according to body mass (moderate intake- 7 mg/kg)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) |
| Placebo | Placebo comparator | Dietary Supplement: Placebo (Biotin Capsules)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 |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- 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
Key exclusion criteria (1 listed)
- Consumption of caffeine and guarana supplements, unless were discontinued for at least two weeks before participating in the study
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 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. | Dietary supplement | Caffeine |
| Placebo (Biotin Capsules)Consumption of biotin (BIOTIN tablets by Myprotein) at the same time as caffeine. | Dietary supplement | Placebo |
Primary outcome
Performance During CrossFit® Workout
Time frame: After 5, 10, 15 and 20 minutes of exercise
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.
Rating of Perceived Exertion during the CrossFit program
Time frame: during the last 10 s of the 5th, 10th, 15th and 20th minute of exercise
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
Blood lactate concentration
Time frame: 1st measurement before the warm up and 2nd measurement one minute after the end of workout (i.e. after 20 min of exercise)
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
3 secondary outcomes
Heart Rate
Time frame: 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
Time frame: baseline (during the 2nd visit)
Maximum heart rate measurement
Time frame: Heart rate was continuously recorded during the test (every 1 s), until exhaustion. The highest heart rate at the time of exhaustion was recorded.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Mar 2025.
- Background: PubMed 30977054Pickering C, Grgic J. Caffeine and Exercise: What Next? Sports Med. 2019 Jul;49(7):1007-1030. doi: 10.1007/s40279-019-01101-0.
- Background: PubMed 33388079Guest 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.
- Background: PubMed 29484512Claudino 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.
- Full data set of measurement performed in the studyLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. All IPD that underlie results in a publication
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
ILIAS SMILIOS, Professor study director
Democritus University of Thrace
VASSILIS MOUGIOS, Professor study director
Aristotle University Of Thessaloniki
GREGORY C. BOGDANIS, Professor study chair
Gregory C. Bogdanis National and Kapodistrian University of Athens, School of Physical Education and Sport Science
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Caffeine administration according to body mass (moderate intake- 7 mg/kg) in people with Healthy, Young Adults and Athletic Performance, run by Democritus University of Thrace at 1 site in Greece.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 26 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Greece. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Performance During CrossFit® Workout (time frame: After 5, 10, 15 and 20 minutes of exercise). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06891469, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Mar 2025.