Effects of caffeine on CrossFit performance

The Effect of Caffeine and Paraxantine Kinetics on Exercise Performance and Psychophysical State in Athletes After Ingestion of Mono- or Multi-ingredient Caffeine-containing Supplements

Phase2; Phase3 Interventional Poznan University of Physical Education · NCT05516212

This study tests how caffeine affects CrossFit athletes' performance by comparing different caffeine supplements to a placebo to see which helps them perform better.

Quick facts

PhasePhase2; Phase3
Study typeInterventional
Enrollment25 (estimated)
Ages18 Years to 40 Years
SexMale
SponsorPoznan University of Physical Education Academic / other
Locations1 site (Poznan)
Trial IDNCT05516212 on ClinicalTrials.gov

What this trial studies

This study investigates how caffeine affects performance in CrossFit athletes by measuring the kinetics of caffeine and its metabolite paraxanthine after ingestion. Participants will consume either a mono-ingredient caffeine supplement, two different multi-ingredient pre-workout supplements, or a placebo, followed by performance assessments through a specific test. Blood and saliva samples will be collected to evaluate muscle damage, recovery indicators, and psychophysiological states. The study employs a double-blind, randomized, placebo-controlled, cross-over design to ensure robust results.

Who should consider this trial

Good fit: Ideal candidates are experienced CrossFit athletes with at least 5 years of training in any sport and 2 years in high-intensity functional training.

Not a fit: Patients with current injuries, serious diseases, or health-related contraindications may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could enhance athletic performance and recovery for CrossFit athletes through optimized caffeine supplementation.

How similar studies have performed: Previous studies have shown positive effects of caffeine on athletic performance, suggesting this approach is supported by existing evidence.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* written informed consent from all participants before the study,
* a current medical clearance to practice sports,
* training experience any sport discipline ≥ 5 years and training experience in HIFT ≥ 2 years,
* performing ≥3 training units per week,
* participating in CrossFit® competitions at least once a year.

Exclusion Criteria:

* current injury,
* any health-related contraindication,
* declared general feeling of being unwell,
* unwilling to follow the study protocol,
* serious disease or metabolic problems,
* smoking and tobacco use,
* presence of infectious disease in the previous 4 weeks of the study.

Where this trial is running

Poznan

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions SupplementationSports NutritionErgogenic SupportDiscipline-specific PerformancePre-workout supplementationcaffeinehigh-intensity interval traininghigh-intensity functional training
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.