The research group previously learned that aspirin, while commonly used to treat muscle pain, did not reduce pain produced by vigorous exercise.

"Muscle contractions produce a host of biochemicals that can stimulate pain. Aspirin blocks only one of those chemicals," Patrick O'Connor, professor of exercise science at UGA's College of Education, said.

"Apparently the biochemical blocked by aspirin has little role in exercise-induced muscle pain."

But the researcher's newest study, published in the latest issue of the Journal of Pain, found that caffeine reduced thigh-muscle pain during cycling exercise.

Participants in the study cycled for 30 minutes on two separate days. The exercise intensity was the same on both days and set to make the riders' thigh muscles hurt. Participants took either a caffeine pill or a placebo one hour before the exercise.

The riders reported feeling substantially less pain in their thigh muscles after taking caffeine compared to after taking the placebo.