Effect of Acute Caffeine Intake Via Caffeinated Gum on Vertical Jump Performance in Female Volleyball Players: A Single-Blind Placebo-Controlled Trial
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 10
- 试验地点
- 1
- 主要终点
- Countermovement Jump Height
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- Single (Participant)
入排标准
- 年龄范围
- 18 Years 至 33 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •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
排除标准
- •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
研究组 & 干预措施
Caffeinated Gum (CAF)
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.
干预措施: Caffeinated chewing gum (Dietary Supplement)
Placebo Gum (PLA)
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.
干预措施: Placebo chewing gum (Dietary Supplement)
结局指标
主要结局
Countermovement Jump Height
时间窗: Within 15 minutes after gum administration.
Change in countermovement jump (CMJ) height measured using a Chronojump contact mat following caffeine or placebo gum ingestion.
次要结局
- Squat Jump Height(Within 15 minutes after gum administration.)
- Block Jump Height(Within 15 minutes after gum administration.)
研究者
Muttalip Ayar
Assistant Professor
University of Beykent