Caffeine Supplementation or Carbohydrate Mouth Rinse Improves Performance.

Area of Science:

• Exercise Physiology
• Sports Nutrition

Background:

• Training volume is crucial for resistance training adaptations like hypertrophy and strength.
• Strategies to optimize training volume are essential for performance enhancement.

Purpose of the Study:

• To investigate the effects of caffeine supplementation, carbohydrate mouth rinse, and their combination on resistance training performance and perceived exertion.
• To test the hypothesis of synergistic effects between caffeine and carbohydrate interventions.

Main Methods:

• A double-blind, randomized, placebo-controlled, crossover study involving 29 physically active women.
• Interventions included caffeine (6.5 mg·kg⁻¹), carbohydrate (6g maltodextrin rinse), combined caffeine and carbohydrate, or placebo.
• Performance was measured by total repetitions; perceived exertion was also recorded.

Main Results:

• Significant improvements in total repetitions for upper and lower body exercises were observed across all intervention conditions compared to placebo (P<0.01).
• No significant differences in total repetitions were found among the caffeine, carbohydrate, or combined interventions.
• The rate of perceived exertion did not significantly differ between conditions, although Bayes factor analysis suggested a trend towards lower RPE with caffeine.

Conclusions:

• Both caffeine supplementation and carbohydrate mouth rinse independently enhance resistance training performance.
• Combining caffeine and carbohydrate does not provide additional performance benefits compared to individual interventions.
• Neither intervention significantly altered the rate of perceived exertion during resistance training.