Bodybuilders and other strength athletes can squeeze more reps out of their sets if they consume the amount of caffeine contained in three cups of coffee before doing a workout. It can also reduce the muscle soreness that plagues some athletes after training. Sports scientists from the University of Rhode Island write about the effect in the Journal of Strength and Conditioning Research.
Caffeine is a mild, legal and harmless stimulant that has been shown in dozens of scientific studies to improve sports performance. This is not only because a dose of caffeine gives athletes extra energy, which makes their training easier, but also because caffeine makes muscle contraction easier. This means for example that strength athletes have more strength in their hands, and therefore can grip their weights better.
In some studies caffeine has also been shown to boost maximal strength, and most studies confirm that it boosts the number of reps that strength athletes can complete per set. [Int J Sport Nutr Exerc Metab. 2007 Oct;17(5):468-77.]
On top of this, caffeine can also help reduce muscle soreness. Caffeine interferes with adenosine, and as a result can weaken pain signals that travel through the nervous system to the brain. [Am J Physiol Regul Integr Comp Physiol. 2003 Feb;284(2):R399-404.]
The researchers wanted to know more about the effect of caffeine on the muscle pain that athletes experience during the first few days after an intensive workout. They did an experiment with nine male students who did weight training at least twice a week. The researchers asked the students to stop using caffeine for a week prior to the start of the experiment.
The students had to train their biceps twice: they first did four sets of 10 reps at 75 percent of the weight with which they could just manage 1 rep; then did another set doing as many reps as they could.
On one occasion the students took 5 mg caffeine per kg bodyweight before training. This is the amount of caffeine you’d find in three strong cups of coffee. On the other occasion the students took a placebo.
As a result of the caffeine supplementation the number of reps the students managed during their last set increased, as the figure below shows.
The figure below shows the amount of muscle soreness the students reported after doing the workout. The soreness was significantly less after the workout with caffeine.
"Caffeine consumption can enhance resistance training performance and yet decrease soreness following resistance training despite doing more work", the researchers conclude. "For an athletic population, this may translate to the ability to perform subsequent exercise sessions with less perceived soreness and possibly increase total work. In addition, the findings of this study suggest that caffeine does act as an ergogenic aid during upper-body resistance training exercise."
Journal of Strength & Conditioning Research. Post Acceptance, 3 September 2013. doi: 10.1097/JSC.0000000000000220.