Caffeinated Gum Use and Volleyball Performance

NCT07597265 | Completed

• 1 other identifier: EGE-25-9.1T-28
• Study Type: interventional
• Target: 11
• Locations: 1 country
• Sites: 1

Brief Summary

This study examined the acute effects of caffeinated chewing gum on volleyball performance in trained female volleyball players. Caffeine is commonly used by athletes to improve performance, but less is known about whether caffeinated gum is useful during volleyball-specific activity. Participants completed three testing sessions in a randomized crossover design. In one session, they chewed placebo gum. In another session, they chewed caffeinated gum containing a single 300 mg dose of caffeine. In the third session, they received the same total amount of caffeine as three separate 100 mg doses given at 30-minute intervals. The study assessed volleyball-specific skill performance, including attack, block, and defense efficiency, during a volleyball-specific skill game. Vertical jump height, heart rate, perceived exertion, side effects, and condition guessing were also recorded.

Conditions

Volleyball Players; Performance

Keywords

Caffeine; Caffeinated gum; Volleyball; Athletic performance; Vertical jump

Outcome Measures

Primary Outcomes (3)

• Attack efficiency

  Attack efficiency was assessed during a 30-minute volleyball-specific skill game using video recordings and Data Volley software. Values were expressed as percentages.

  During the 30-minute volleyball-specific skill game in each experimental trial

• Block efficiency

  Block efficiency was assessed during a 30-minute volleyball-specific skill game using video recordings and Data Volley software. Values were expressed as percentages.

  During the 30-minute volleyball-specific skill game in each experimental trial

• Defense efficiency

  Defense efficiency was assessed during a 30-minute volleyball-specific skill game using video recordings and Data Volley software. Values were expressed as percentages.

  During the 30-minute volleyball-specific skill game in each experimental trial

Secondary Outcomes (3)

• Change in vertical jump height

  From immediately before to immediately after each experimental trial

• Heart rate

  Continuously during each experimental trial

• Change in rating of perceived exertion

  From immediately before to immediately after each experimental trial

Other Outcomes (1)

• Side effects

  Immediately after each experimental trial

Study Arms (6)

Placebo, Single-Dose Caffeine, Partial-Dose Caffeine Arm Type: Experimental

EXPERIMENTAL

Participants received placebo gum in the first session, single-dose caffeinated gum in the second session, and partial-dose caffeinated gum in the third session. Sessions were separated by one week.

Dietary Supplement: Single-dose caffeinated gum; Dietary Supplement: Partial-dose caffeinated gum; Dietary Supplement: Placebo gum

Placebo, Partial-Dose Caffeine, Single-Dose Caffeine

EXPERIMENTAL

Participants received placebo gum in the first session, partial-dose caffeinated gum in the second session, and single-dose caffeinated gum in the third session. Sessions were separated by one week.

Dietary Supplement: Single-dose caffeinated gum; Dietary Supplement: Partial-dose caffeinated gum; Dietary Supplement: Placebo gum

Single-Dose Caffeine, Placebo, Partial-Dose Caffeine

EXPERIMENTAL

Participants received single-dose caffeinated gum in the first session, placebo gum in the second session, and partial-dose caffeinated gum in the third session. Sessions were separated by one week.

Dietary Supplement: Single-dose caffeinated gum; Dietary Supplement: Partial-dose caffeinated gum; Dietary Supplement: Placebo gum

Single-Dose Caffeine, Partial-Dose Caffeine, Placebo

EXPERIMENTAL

Participants received single-dose caffeinated gum in the first session, partial-dose caffeinated gum in the second session, and placebo gum in the third session. Sessions were separated by one week.

Dietary Supplement: Single-dose caffeinated gum; Dietary Supplement: Partial-dose caffeinated gum; Dietary Supplement: Placebo gum

Partial-Dose Caffeine, Placebo, Single-Dose Caffeine

EXPERIMENTAL

Participants received partial-dose caffeinated gum in the first session, placebo gum in the second session, and single-dose caffeinated gum in the third session. Sessions were separated by one week.

Dietary Supplement: Single-dose caffeinated gum; Dietary Supplement: Partial-dose caffeinated gum; Dietary Supplement: Placebo gum

Partial-Dose Caffeine, Single-Dose Caffeine, Placebo

EXPERIMENTAL

Participants received partial-dose caffeinated gum in the first session, single-dose caffeinated gum in the second session, and placebo gum in the third session. Sessions were separated by one week.

Dietary Supplement: Single-dose caffeinated gum; Dietary Supplement: Partial-dose caffeinated gum; Dietary Supplement: Placebo gum

Interventions

Single-dose caffeinated gum DIETARY_SUPPLEMENT

Participants chewed three pieces of caffeinated gum containing 100 mg caffeine per piece, providing a total dose of 300 mg caffeine. The gum was chewed for 5 minutes and then discarded.

Also known as: Caffeine gum, Caffeinated chewing gum

Partial-Dose Caffeine, Placebo, Single-Dose Caffeine; Partial-Dose Caffeine, Single-Dose Caffeine, Placebo; Placebo, Partial-Dose Caffeine, Single-Dose Caffeine; Placebo, Single-Dose Caffeine, Partial-Dose Caffeine Arm Type: Experimental; Single-Dose Caffeine, Partial-Dose Caffeine, Placebo; Single-Dose Caffeine, Placebo, Partial-Dose Caffeine

Partial-dose caffeinated gum DIETARY_SUPPLEMENT

Participants received three separate pieces of caffeinated gum containing 100 mg caffeine per piece. One piece was chewed for 5 minutes at each administration time point, with doses given at 30-minute intervals, providing a total dose of 300 mg caffeine.

Also known as: Caffeine gum, Caffeinated chewing gum

Partial-Dose Caffeine, Placebo, Single-Dose Caffeine; Partial-Dose Caffeine, Single-Dose Caffeine, Placebo; Placebo, Partial-Dose Caffeine, Single-Dose Caffeine; Placebo, Single-Dose Caffeine, Partial-Dose Caffeine Arm Type: Experimental; Single-Dose Caffeine, Partial-Dose Caffeine, Placebo; Single-Dose Caffeine, Placebo, Partial-Dose Caffeine

Placebo gum DIETARY_SUPPLEMENT

Participants chewed caffeine-free placebo gum for 5 minutes. The placebo gum was selected to be similar in shape and color to the caffeinated gum.

Also known as: Caffeine-free gum, Placebo chewing gum

Partial-Dose Caffeine, Placebo, Single-Dose Caffeine; Partial-Dose Caffeine, Single-Dose Caffeine, Placebo; Placebo, Partial-Dose Caffeine, Single-Dose Caffeine; Placebo, Single-Dose Caffeine, Partial-Dose Caffeine Arm Type: Experimental; Single-Dose Caffeine, Partial-Dose Caffeine, Placebo; Single-Dose Caffeine, Placebo, Partial-Dose Caffeine

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Female volleyball players aged 18 to 35 years.
• Apparently healthy.
• Daily caffeine intake ≤300 mg.
• Minimum of 5 years of regular volleyball training experience.
• Training for at least 120 minutes at least 3 days per week.
• Competing in national or international volleyball matches.
• Provided written informed consent before participation.

You may not qualify if:

• Serious injury or trauma within the past 6 months that could affect volleyball performance.
• Illness or inability to continue the study protocol during the research period.
• Development of side effects during caffeinated gum administration that prevented continuation.
• Regular alcohol or drug use that could affect the study outcomes.

Sponsors & Collaborators

• Ege University: lead

Study Sites (1)

Ege University, Faculty of Sport Sciences

Izmir, Bornova, 35040, Turkey (Türkiye)

Location

Study Design

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

Study Record Dates

• First Submitted: May 11, 2026
• First Posted: May 19, 2026
• Study Start: August 5, 2025
• Primary Completion: April 23, 2026
• Study Completion: April 23, 2026
• Last Updated: May 19, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)