Acute Effects of Tribulus Terrestris on Anaerobic Power and Sprint Performance in Combat Sport Athletes

This trial is designed to evaluate the acute ergogenic potential of Tribulus terrestris supplementation in combat sport athletes. Tribulus terrestris has traditionally been marketed as a natural testosterone booster and performance enhancer, yet its acute effects on high-intensity exercise performance remain unclear.

Design and Methods

Participants: 28 trained male athletes (Kickboxing n=12, Muay Thai n=10, Taekwondo n=6), aged 18-30 years, with at least 2 years of competitive training experience.

Design: Randomized, double-blind, placebo-controlled, crossover.

Intervention: A single dose of 625 mg Tribulus terrestris (40% saponins) or matched placebo (cellulose). Supplements will be ingested 60 minutes before testing.

Procedures: After a standardized warm-up, participants will complete a 30-second Wingate test on a Monark cycle ergometer (resistance = 10% body mass) to measure peak power, mean power, and fatigue index. Following 10 minutes of recovery, participants will perform 20 m and 100 m sprint tests using double-beam photocells (Witty timing system). Each participant will perform both supplementation conditions with a ≥72 h wash-out.

Outcomes Primary outcomes: Wingate peak power (W, W/kg), mean power (W, W/kg). Secondary outcomes: 20 m and 100 m sprint times (s).

Ethics: Approved by the Ethics Committee of Atatürk University (Protocol No: E-70400699-000-2500104927). Written informed consent will be obtained from all participants.

• Tribulus terrestris extract (Dietary supplement): 625 mg oral capsule (40% saponins), single dose
• Cellulose capsule (placebo) (Other): Oral cellulose capsule, identical in appearance

Primary outcomes

• Peak Power Output (W, W/kg) - Wingate Test [Measured once, 60 minutes after supplementation, during the Wingate test session (single-day assessment).]: Maximum anaerobic power generated during the 30-second Wingate cycling test performed against a resistance equal to 10% of body mass.

Secondary outcomes

• Mean Power Output (W, W/kg) - Wingate Test [Measured once, 60 minutes after supplementation, during the Wingate test session (single-day assessment).]: verage anaerobic power calculated across the full 30-second Wingate cycling test.

Sex: Male, ages: 18 Years to 30 Years, accepts healthy volunteers

Inclusion Criteria:

* Male athletes aged 18-30 years
* Engaged in combat sports (kickboxing, Muay Thai, or taekwondo)
* Minimum 2 years of continuous training experience
* Training at least 4 sessions per week
* Free from injury or illness at the time of testing
* Provided written informed consent

Exclusion Criteria:

* Use of ergogenic supplements, anabolic steroids, or hormonal treatments within the past 3 months
* Consumption of caffeine, alcohol, or performance-enhancing substances within 24 hours before testing
* Current musculoskeletal injury or medical condition that may limit performance
* Any chronic disease or contraindication to high-intensity exercise