Caffeine increases performance during repeated sprints

Caffeine is an effective supplement for increasing strength and energy. It is currently permitted in Olympic sports, but banned in college and high school sports. Most studies show that even moderate doses of caffeine increase performance in high-intensity and endurance sports, reduce fatigue, improve concentration and increase mental alertness. Many bodybuilders use caffeine supplements before training to increase training intensity and provide more energy. However, scientific studies disagree with the effectiveness of caffeine as a performance-enhancing supplement for high-intensity training.
A British study conducted under the direction of Mark Glaister at St. Mary's University College showed that caffeine (at an average dosage of 385 milligrams of caffeine) increased performance during repeated short sprints (12 x 30 meter sprints at 35 second intervals). Compared to a placebo, caffeine increased the maximum sprint performance by 0.06 seconds, which corresponds to an improvement of 1.4 percent. In addition, caffeine delayed fatigue during exercise by 1.2 percent.
Caffeine did not make sprinting seem easier (perceived exertion), but it increased heart rate more than the placebo. Caffeine had only a minor effect on repeated sprint performance. However, this difference could make the difference between winning and losing.
(Medicine Science Sports Exercise, 40: 1835-1840, 2008)