Clinical Research Directory

Caffeine and Wrestling Performance in Male Wrestlers of Different Weight Classes: A Randomized Crossover Trial

Caffeine is commonly used by athletes to improve performance, but not everyone responds to it in the same way. In weight-class sports like wrestling, athletes are grouped by body weight. When caffeine is dosed based on body weight (4 mg per kg), heavier athletes receive a larger total amount of caffeine than lighter athletes. This study asked whether the effects of caffeine on wrestling performance and side effects differ across wrestling weight classes. Ninety-five male wrestlers (30 lightweight, 36 middleweight, and 29 heavyweight) completed two testing sessions: one after taking caffeine (4 mg/kg) and one after taking a placebo (an inactive capsule). Neither the wrestlers nor the researchers knew which capsule was given in each session. Each session included a countermovement jump test and a wrestling-specific fitness test that involved throwing a wrestling dummy. Heart rate, perceived exertion, and self-reported symptoms were also recorded. The study found that lightweight and middleweight wrestlers generally performed better after caffeine, while heavyweight wrestlers showed no performance improvement and reported more side effects, such as anxiety, rapid heartbeat, stomach discomfort, and insomnia. These differences occurred even though all wrestlers received the same caffeine dose relative to their body weight. The results suggest that a standard body-weight-based caffeine dose may not work equally well for all wrestlers. Lighter wrestlers may benefit more, while heavier wrestlers may experience more side effects without performance gains. These findings support the need for individualized caffeine dosing strategies in wrestling and similar weight-class sports. However, because body weight, total caffeine dose, and other weight-class-related factors were not separated in this study, the results should be considered exploratory and do not establish weight-specific recommendations.

The Impact of Meaningful vs. Neutral Symbol Visualization on Sport-Related Performance

The study will provide preliminary information for sport psychology and performance research by examining the relationship among symbolic meaning, physiological response, psychological response, and performance-related measures. It may help determine whether a personally meaningful animal symbol is associated with different HRV, trait sport-confidence, rope climbing speed, and grip-strength responses than a neutral wooden-block symbol. Results may help refine future studies of visualization, competitive identity, psychological skills training, and performance. Because this is a pilot study, findings will be interpreted cautiously and used primarily to assess feasibility, estimate preliminary effects, and improve the protocol for future research.