At the 2016 Summer Olympics, Michael Phelps added to the collection of medals that make him "the most decorated Olympian of all time." But the medallions hanging around his neck weren't the only "decorations" that generated attention. The media and public also became fascinated by the tennis ball-sized red circles on his upper back and shoulders.

These welts are the result of cupping, a technique dating back to ancient Greece (making it an appropriate topic during the Olympics) that is common practice in traditional Chinese medicine.¹ 

Dry cupping involves the use of negative pressure to create a suctioning effect without any skin perforation.² Wet cupping also uses skin suctioning, but with added superficial skin incisions to induce bleeding.³ Cups typically are left on the skin for 5-20 minutes, creating a circular-shaped ecchymosis, which may last for days or weeks. Increasing the time and/or pressure exacerbates the ecchymosis.²

Thanks to Phelps, an ancient technique seemed new again. And, in a cycle that's all too familiar, viewers became intrigued by some "sanctioned," never-before-seen performance enhancer that gets worldwide exposure on the Olympic stage.