Athletic PerformanceCAF-GUMNCT07240506
Effect of Caffeinated Chewing Gum on Vertical Jump Performance in Female Volleyball Players
A study testing Caffeinated chewing gum in people with Athletic Performance, run by Muttalip Ayar at 1 site in Turkey (Türkiye).
Trial summary
This study aimed to examine the acute effects of caffeine intake through caffeinated chewing gum on the vertical jump performance of professional female volleyball players. Ten athletes from the Turkish Women's Volleyball First League voluntarily participated in this single-blind, placebo-controlled, randomized… Read more about this study
- Who is it for?
- Ages 18 to 33 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Athletic Performance
- What is being tested?
- Caffeinated chewing gum
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 10 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 10 Feb 2025to 1 May 2025
- 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 33 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Self-identified female athletes aged 18-33 years Professional volleyball players actively competing in the Turkish Women's Volleyball First League Minimum of 3 years of competitive volleyball experience Healthy individuals without any diagnosed medical conditions Willing to abstain from caffeine-containing products for at least 24 hours before each testing session Voluntarily agreed to participate and provided written informed consent
Who cannot join
- Known cardiovascular, metabolic, or neurological disorders Current use of medications or supplements affecting physical performance or caffeine metabolism Pregnancy or breastfeeding History of caffeine sensitivity, intolerance, or allergy Failure to comply with pre-test instructions (e.g., caffeine restriction, rest period) Musculoskeletal injuries preventing full jump performance
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Yeşilyurt Sports Club - Women's Volleyball Team Training Facility
Istanbul, Bakırköy, 34149
About this study
Official title: Effect of Acute Caffeine Intake Via Caffeinated Gum on Vertical Jump Performance in Female Volleyball Players: A Single-Blind Placebo-Controlled Trial
This study aimed to examine the acute effects of caffeine intake through caffeinated chewing gum on the vertical jump performance of professional female volleyball players. Ten athletes from the Turkish Women's Volleyball First League voluntarily participated in this single-blind, placebo-controlled, randomized crossover study. Each athlete completed two test sessions: one with caffeinated gum containing 200 mg of caffeine and one with a caffeine-free placebo gum. After chewing the gum for 5 minutes, participants performed three types of vertical jump tests: squat jump, countermovement jump, and block jump. The results showed that caffeinated gum significantly improved countermovement jump height compared with the placebo, while no significant differences were observed for squat or block jumps. The findings suggest that caffeine in gum form may enhance explosive performance in sports requiring rapid power output, such as volleyball.
Read the detailed description
Caffeine is a well-established ergogenic aid known to improve endurance, strength, and cognitive performance. However, limited evidence exists on its acute effects in female team-sport athletes. This study was designed to evaluate the impact of acute caffeine intake via caffeinated chewing gum on vertical jump performance among professional female volleyball players. The research employed a randomized, single-blind, placebo-controlled crossover design.
Ten professional athletes aged 18-33 years from the Yeşilyurt Sports Club Women's A Team, competing in the Turkish Volleyball Federation Women's 1st League, were included. Participants underwent two experimental sessions: one involving caffeinated gum (CAF, 200 mg total caffeine from two 100 mg pieces) and one involving placebo gum (PLA, identical but caffeine-free), separated by a six-day washout period. The gums were chewed for 5 minutes, and jump performance tests were conducted 15 minutes later.
Vertical jump performance was evaluated using a Chronojump jump mat for three jump types: squat jump (SJ), countermovement jump (CMJ), and block jump (BJ). Each test included three attempts, with the highest score recorded for analysis. Data were analyzed with paired-sample t-tests using SPSS 27.0, with significance set at p<0.05.
The results showed that caffeine gum significantly increased CMJ height compared with the placebo (p<0.05), but no significant effects were observed for SJ or BJ performance. The findings indicate that caffeine in gum form may acutely improve explosive performance involving stretch-shortening cycle movements.
The study was approved by the Non-Interventional Clinical Research Ethics Committee of Istanbul Medipol University (Approval No: E-10840098-202.3.02-735). All participants provided informed consent prior to data collection.
- Conditions
- Athletic Performance
- Being tested
- Caffeinated chewing gum, Placebo chewing gum
- Keywords
- Caffeine, Caffeinated Gum, Female Athletes, Jump Performance, Sports Nutrition
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Caffeinated chewing gumDietary supplement
Two pieces of caffeinated chewing gum providing 200 mg total caffeine; administered 15 minutes before performance testing.
Placebo chewing gumDietary supplement
Two pieces of placebo chewing gum identical in appearance and flavor to the caffeinated gum but containing no caffeine; administered 15 minutes before performance testing.
| Study group | Role | What they receive |
|---|---|---|
| Caffeinated Gum (CAF) | Experimental | Participants chewed two pieces of caffeinated chewing gum containing a total of 200 mg caffeine (2 × 100 mg). After chewing for 5 minutes, they performed squat jump, countermovement jump, and block jump tests. Receives: Dietary Supplement: Caffeinated chewing gum |
| Placebo Gum (PLA) | Placebo comparator | Participants chewed two pieces of placebo chewing gum identical in appearance and flavor but containing no caffeine. After chewing for 5 minutes, they performed the same vertical jump tests as in the caffeinated condition. Receives: Dietary Supplement: Placebo chewing gum |
What is being measured
The primary outcome is the main question the study is designed to answer.
Countermovement Jump Height
Change in countermovement jump (CMJ) height measured using a Chronojump contact mat following caffeine or placebo gum ingestion.
Measured: Within 15 minutes after gum administration.
Secondary outcomes (2)
Squat Jump Height
Change in squat jump (SJ) height measured using a Chronojump contact mat after caffeine or placebo gum ingestion.
Measured: Within 15 minutes after gum administration.
Block Jump Height
Change in block jump (BJ) height measured using a Chronojump contact mat after caffeine or placebo gum ingestion.
Measured: Within 15 minutes after gum administration.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Nov 2025
- Study start10 Feb 2025
- Primary completion20 Feb 2025
- Study completion1 May 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Athletic PerformanceStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 10 participants (actual)
Sponsor and investigators
- Lead sponsor
- Muttalip Ayar
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Muttalip Ayar, University of Beykent
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07240506
- Sponsor's protocol ID
- E-10840098-202.3.02-735
- Acronym
- CAF-GUM
- Status last verified
- Nov 2025
- First submitted
- 16 Nov 2025
- Last updated
- 28 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data (IPD) will not be shared because the dataset contains identifiable information related to a small group of professional athletes. Only summarized results are available within the published manuscript and supplementary materials upon reasonable request.
Study at a glance
From the registry record, last updated by the sponsor on 28 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Acute Caffeine Intake Via Caffeinated Gum on Vertical Jump Performance in Female Volleyball Players: A Single-Blind Placebo-Controlled Trial
- ClinicalTrials.gov ID
- NCT07240506
- Acronym / sponsor ID
- CAF-GUM / E-10840098-202.3.02-735
- Conditions
- Athletic Performance
- Keywords
- Caffeine, Caffeinated Gum, Female Athletes, Jump Performance, Sports Nutrition
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 10 participants (actual)
- Lead sponsor
- Muttalip AyarUniversity, hospital or other
- Study start
- 10 Feb 2025 (actual)
- Primary completion
- 20 Feb 2025 (actual)
- Study completion
- 1 May 2025 (actual)
- First posted
- 21 Nov 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.
This study aimed to examine the acute effects of caffeine intake through caffeinated chewing gum on the vertical jump performance of professional female volleyball players. Ten athletes from the Turkish Women's Volleyball First League voluntarily participated in this single-blind, placebo-controlled, randomized crossover study. Each athlete completed two test sessions: one with caffeinated gum containing 200 mg of caffeine and one with a caffeine-free placebo gum. After chewing the gum for 5 minutes, participants performed three types of vertical jump tests: squat jump, countermovement jump, and block jump. The results showed that caffeinated gum significantly improved countermovement jump height compared with the placebo, while no significant differences were observed for squat or block jumps. The findings suggest that caffeine in gum form may enhance explosive performance in sports requiring rapid power output, such as volleyball.
Detailed description
Caffeine is a well-established ergogenic aid known to improve endurance, strength, and cognitive performance. However, limited evidence exists on its acute effects in female team-sport athletes. This study was designed to evaluate the impact of acute caffeine intake via caffeinated chewing gum on vertical jump performance among professional female volleyball players. The research employed a randomized, single-blind, placebo-controlled crossover design.
Ten professional athletes aged 18-33 years from the Yeşilyurt Sports Club Women's A Team, competing in the Turkish Volleyball Federation Women's 1st League, were included. Participants underwent two experimental sessions: one involving caffeinated gum (CAF, 200 mg total caffeine from two 100 mg pieces) and one involving placebo gum (PLA, identical but caffeine-free), separated by a six-day washout period. The gums were chewed for 5 minutes, and jump performance tests were conducted 15 minutes later.
Vertical jump performance was evaluated using a Chronojump jump mat for three jump types: squat jump (SJ), countermovement jump (CMJ), and block jump (BJ). Each test included three attempts, with the highest score recorded for analysis. Data were analyzed with paired-sample t-tests using SPSS 27.0, with significance set at p<0.05.
The results showed that caffeine gum significantly increased CMJ height compared with the placebo (p<0.05), but no significant effects were observed for SJ or BJ performance. The findings indicate that caffeine in gum form may acutely improve explosive performance involving stretch-shortening cycle movements.
The study was approved by the Non-Interventional Clinical Research Ethics Committee of Istanbul Medipol University (Approval No: E-10840098-202.3.02-735). All participants provided informed consent prior to data collection.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Caffeinated Gum (CAF) | Experimental | Dietary Supplement: Caffeinated chewing gumParticipants chewed two pieces of caffeinated chewing gum containing a total of 200 mg caffeine (2 × 100 mg). After chewing for 5 minutes, they performed squat jump, countermovement jump, and block jump tests. |
| Placebo Gum (PLA) | Placebo comparator | Dietary Supplement: Placebo chewing gumParticipants chewed two pieces of placebo chewing gum identical in appearance and flavor but containing no caffeine. After chewing for 5 minutes, they performed the same vertical jump tests as in the caffeinated condition. |
Who may qualify
- Ages
- 18 to 33 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Self-identified female athletes aged 18-33 years Professional volleyball players actively competing in the Turkish Women's Volleyball First League Minimum of 3 years of competitive volleyball experience Healthy individuals without any diagnosed medical conditions Willing to abstain from caffeine-containing products for at least 24 hours before each testing session Voluntarily agreed to participate and provided written informed consent
Key exclusion criteria (1 listed)
- Known cardiovascular, metabolic, or neurological disorders Current use of medications or supplements affecting physical performance or caffeine metabolism Pregnancy or breastfeeding History of caffeine sensitivity, intolerance, or allergy Failure to comply with pre-test instructions (e.g., caffeine restriction, rest period) Musculoskeletal injuries preventing full jump performance
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 |
|---|---|---|
| Caffeinated chewing gumTwo pieces of caffeinated chewing gum providing 200 mg total caffeine; administered 15 minutes before performance testing. | Dietary supplement | Caffeinated Gum (CAF) |
| Placebo chewing gumTwo pieces of placebo chewing gum identical in appearance and flavor to the caffeinated gum but containing no caffeine; administered 15 minutes before performance testing. | Dietary supplement | Placebo Gum (PLA) |
Primary outcome
Countermovement Jump Height
Time frame: Within 15 minutes after gum administration.
Change in countermovement jump (CMJ) height measured using a Chronojump contact mat following caffeine or placebo gum ingestion.
2 secondary outcomes
Squat Jump Height
Time frame: Within 15 minutes after gum administration.
Block Jump Height
Time frame: Within 15 minutes after gum administration.
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 28 Nov 2025.
- Individual participant dataSharing planned: No. Individual participant data (IPD) will not be shared because the dataset contains identifiable information related to a small group of professional athletes. Only summarized results are available within the published manuscript and supplementary materials upon reasonable request.
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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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Caffeinated chewing gum in people with Athletic Performance, run by Muttalip Ayar at 1 site in Turkey (Türkiye).
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 1 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 28 Nov 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 Turkey (Türkiye). 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?
Countermovement Jump Height (time frame: Within 15 minutes after gum administration.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 28 Nov 2025.