Skip to main content
OpenTrials
Completed

NCT Number: NCT07458594

Combined Caffeine and Rhodiola Rosea on Aerial Duel Performance in Soccer

This study will examine whether caffeine (CAF) and Rhodiola rosea (RHO) supplementation, taken alone or in combination, can improve explosive performance and soccer-specific aerial duel performance in trained male soccer players. In a randomized, double-blind, placebo-controlled, parallel design, participants will be assigned to placebo, RHO, CAF, or RHO+CAF for 4 weeks. Performance outcomes will be assessed before and after the intervention using countermovement jump measures (including early take-off impulse) and standardized heading tests (heading reach height, ball exit velocity, and heading duel success rate), with additional measures of neck isometric strength and perceived exertion.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Aerial Duel Performance in Soccer Players

Age range

18 year–30 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

China Football Institute, Beijing Sport University, Beijing, Beijing Municipality, China

Loading trial locations.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy male soccer players from the Beijing Sport University team.

Systematic soccer-specific training background and stable competitive level.

Suitable for high-intensity physical testing based on the Physical Activity Readiness Questionnaire (PAR-Q).

Exclusion criteria

  • History of neuromuscular or musculoskeletal system diseases.

Intake of caffeine (coffee/tea), other supplements, ergogenic aids, or alcohol within the last 3 months.

Current use of antidepressants or central nervous system stimulants.

Smokers.

Treatment and study plan

Caffeine

Dietary Supplement

Anhydrous caffeine capsules administered at a dose of 3 mg/kg body weight. Taken as a single dose 30 minutes prior to the physical performance tests.

Rhodiola rosea extract

Dietary Supplement

Standardized Rhodiola rosea extract capsules. Daily total dosage of 2.4 g (containing approx. 12 mg salidroside), taken twice daily (before breakfast and lunch) for 30 days.

Placebo

Dietary Supplement

Appearance-matched capsules containing inert ingredients (starch or rice flour).

Primary outcomes

  1. Early takeoff impulse (Impulse₀-₂₀₀)

    Time frame: Baseline (Day 0) and Post-intervention (Day 30), measured under both non-fatigued and fatigued conditions.

    Calculated as the integration of vertical force over the first 200 ms of the countermovement jump (CMJ) takeoff phase, relative to body mass (N·s·kg-¹). This measures the capacity for rapid force production.

Secondary outcomes

  1. Heading contact height

    Time frame: Baseline (Pre-test) and 4 weeks (Post-test), including measurements under both non-fatigued and fatigued conditions at each time point.

    Participants perform a header and touch a football suspended on a vertical jump tester with their forehead. The highest touch height from three trials is recorded to reflect aerial reach capacity.

  2. Heading Ball Velocity

    Time frame: Baseline (Pre-test) and 4 weeks (Post-test), including measurements under both non-fatigued and fatigued conditions at each time point.

    The maximum velocity of the ball after heading is measured using a speed device. A ball machine is used to ensure consistent delivery direction and speed. This measures momentum transfer efficiency and technical execution.

  3. Aerial Duel Success Rate

    Time frame: Baseline (Pre-test) and 4 weeks (Post-test), including measurements under both non-fatigued and fatigued conditions at each time point.

    Calculated as the percentage of successful duels out of a fixed number of trials in a standardized head-to-head setting. Success is defined as effectively contacting the ball first and directing it toward a target area.

  4. Neck Isometric Strength

    Time frame: Baseline (Pre-test) and 4 weeks (Post-test).

    Maximum isometric force measured in neck flexion and extension using a handheld dynamometer. Values are normalized to body mass ($N \\cdot kg^{-1}$) to assess the stability of the head-trunk system.

  5. Rate of Perceived Exertion (RPE)

    Time frame: Immediately after the fatigue-induction protocol and post-fatigue testing at Baseline and 4 weeks.

    Subjective effort level reported by participants on a scale of 1 to 10 (1 = nearly no effort, 10 = extreme effort) immediately following the fatigue protocol and post-fatigue tests.

Sponsors and collaborators

Lead sponsor

Beijing Sport University

Other

Registry information

Official study title

Effects of Combined Caffeine and Rhodiola Rosea Supplementation on Aerial Duel Performance Under Fatigue in Soccer Players

Acronym: CCRP-AD

Important dates

Study start
2025
Primary completion
2025
Study completion
2026
First posted
Mar 9, 2026
Registry last updated
Mar 9, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.