Placebo Effect in Field-Based Physical Performance

This study aims to investigate the placebo (PLA) effect on physical performance across different sports disciplines in real-world, field-based settings. The study investigates how participant expectations and beliefs regarding caffeine (CAF) intake influence physical performance and psychomotor function outside the controlled laboratory environment. Healthy, physically active adults (n = 120) from diverse sports backgrounds will be randomly assigned to receive caffeine, placebo, or no intervention. Participants will perform discipline-specific field exercise tests (e.g., running-based protocols or repeated sprint protocols) while physiological responses are monitored using wearable technology. Physical performance outcomes and psychomotor responses will be analyzed to evaluate the real-world impact of the placebo effect and to distinguish the pharmacological effects of caffeine from those driven by psychological expectations across different athletic settings.

Inclusion Criteria: * Age between 20 and 35 years, * Healthy adults, * Regular physical activity, * Normal or corrected-to-normal vision, * Habitual caffeine consumption. Exclusion Criteria: * History of neurological, psychiatric, cardiovascular, or metabolic disorders, * Current use of medication or supplements affecting the central nervous system, * Musculoskeletal injuries that would impair physical performance, * No habitual caffeine consumption or severe negative side effects of caffeine, * Diagnosed sleep disorders or chronic fatigue, * Diagnosed major depressive disorder or other severe psychiatric conditions, * Presence of any menstrual disorders, * Inability to attend all experimental study visits.