Effect of Caffeinated Chewing Gum on Vertical Jump Performance in Female Volleyball Players

NCT07240506 | Completed

• 1 other identifier: E-10840098-202.3.02-735
• Study Type: interventional
• Target: 10
• Locations: 1 country
• Sites: 1

Brief 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 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.

Conditions

Athletic Performance

Keywords

Caffeine; Caffeinated Gum; Female Athletes; Jump Performance; Sports Nutrition

Outcome Measures

Primary Outcomes (1)

• Countermovement Jump Height

  Change in countermovement jump (CMJ) height measured using a Chronojump contact mat following caffeine or placebo gum ingestion.

  Within 15 minutes after gum administration.

Secondary Outcomes (2)

• Squat Jump Height

  Within 15 minutes after gum administration.

• Block Jump Height

  Within 15 minutes after gum administration.

Study Arms (2)

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.

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.

Dietary Supplement: Placebo chewing gum

Interventions

Caffeinated chewing gum DIETARY_SUPPLEMENT

Two pieces of caffeinated chewing gum providing 200 mg total caffeine; administered 15 minutes before performance testing.

Caffeinated Gum (CAF)

Placebo chewing gum DIETARY_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.

Placebo Gum (PLA)

Eligibility Criteria

• Age: 18 Years - 33 Years
• Gender Eligibility Details: Only self-identified female athletes were eligible to participate in this study. Participants were professional volleyball players competing in the Turkish Women's Volleyball First League.
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Muttalip Ayar: lead

Study Sites (1)

Yeşilyurt Sports Club - Women's Volleyball Team Training Facility

Istanbul, Bakırköy, 34149, Turkey (Türkiye)

Location

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: November 16, 2025
• First Posted: November 21, 2025
• Study Start: February 10, 2025
• Primary Completion: February 20, 2025
• Study Completion: May 1, 2025
• Last Updated: November 28, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)