Athletes and sports massage therapists know that delayed onset muscle soreness, or exercise-induced muscle damage, is one of the most common sports injuries.

Until now, there hasn’t been a reliable method of quantifying muscle soreness, which has made assessing treatments difficult, the new study’s investigators say.

“Traditionally, muscle soreness has been measured using the visual analogue scale,” states a press release from Journal of Visualized Experiments, which will publish the study. “Participants mark their level of agreement to a statement along a continuous line.”

With the new technique, rather than measuring soreness subjectively, investigators from Loma Linda and Asuza Pacific Universities used thermal imaging to detect subtle changes in the temperature of the skin above exercised muscles.

“The main advantage of this technique,” said paper author Jerrold Petrofsky, Ph.D., “is that unlike visual scales, which are kind of a subjective measure of whether someone is sore or not, this technique gives you quantifiable, absolute data.” This allows for earlier diagnosis and quicker treatment of soreness, the press release noted.