Caffeine Supplementation Is Beneficial for the Pulling Performance of Indoor Tug-of-War Athletes

This study investigated the effects of caffeine supplementation, carbohydrate mouth rinsing, and combined caffeine supplementation with carbohydrate mouth rinsing on the pulling performance and ratings of perceived exertion in indoor tug-of-war athletes. Eighteen tug-of-war athletes were recruited as participants. They underwent four supplementation protocols in a double-blind, single-factor, repeated-measures design: caffeine supplementation (CAF), carbohydrate solution mouth rinsing (CHO), combined caffeine supplementation with carbohydrate mouth rinsing (CAF-CHO), and a placebo (PLA). Each participant performed a maximal pulling test at 80% of their maximum pulling force, and the duration was recorded. Ratings of perceived exertion were also assessed. Data were analyzed using SPSS version 25.0 for Windows, and effect sizes (ES) were calculated. The main findings were as follows: (1) The CAF-CHO group showed a significantly longer pulling duration than the PLA and CHO groups (165.0 ± 69.2 s vs. 137.4 ± 48.9 s vs. 135.6 ± 66.6 s). (2) The CAF group also demonstrated a significantly longer pulling duration than the CHO group (162.0 ± 14.1 s vs. 135.6 ± 66.6 s). (3) Both the CAF-CHO and CAF groups exhibited large effect sizes (ω² > 0.14) compared to the PLA and CHO groups. Both caffeine supplementation combined with carbohydrate mouth rinsing and caffeine supplementation alone can significantly enhance the duration of 80% maximal pulling performance in indoor tug-of-war athletes, with the primary effect attributed to caffeine. These results provide practical strategies for coaches and athletes to suppress fatigue and improve pulling performance during competitions or training sessions for indoor tug-of-war.