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.

This randomized, placebo-controlled, crossover study investigated whether the pattern of caffeinated gum administration affects volleyball-specific performance in trained female volleyball players. Participants completed one familiarization session and three experimental sessions separated by one week. The experimental conditions were placebo gum, single-dose caffeinated gum, and partial-dose caffeinated gum.

In the single-dose condition, participants chewed three pieces of caffeinated gum containing a total of 300 mg caffeine for 5 minutes. In the partial-dose condition, participants chewed one piece of caffeinated gum containing 100 mg caffeine at three different time points, with 30-minute intervals between doses. In the placebo condition, participants chewed caffeine-free gum for 5 minutes.

Each testing session included volleyball-specific activities and a 30-minute volleyball-specific skill game. Attack, block, and defense efficiency were assessed using video recordings and Data Volley software. Vertical jump height was measured before and after the volleyball-specific activity. Heart rate was recorded during the session, and rating of perceived exertion was assessed before and after the session. Participants were also asked to report side effects and to guess which condition they had received after each session.

Inclusion Criteria:

• 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.

Exclusion Criteria:

• 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.

Individual participant data will not be shared because the dataset contains participant-level performance and physiological data from a small group of elite female volleyball players, which may increase the risk of participant identification.