Michael Phelps’ Back Bruises Explained

It involves a therapist heating small glass cups, then placing them on the skin and pulling them from the body to loosen and relax the muscles.

There’s no way to study if cupping truly offers benefits or if it’s a placebo effect because studies like that include a group who get a fake version of the treatment or procedure and you can’t really fake fishbowl suction cups.

In reality, the mysterious bruises are from “cupping therapy”. Former Olympic swimmer Natalie Coughlin has also previously posted pictures of herself going through a cupping therapy.

In a more modern version of cupping, a rubber pump attached to the jar is used to create the vacuum.

Other Team USA athletes are said to be fans of the technique.

Michael Phelps and the Olympic swimmers arrived in prime time Sunday night and there was something and unmistakable on their bodies: round circles. You’re not totally wrong. That’s a lot of bias.

Another 2012 study concluded that “cupping massage is no more effective than progressive muscle relaxation in reducing chronic non-specific neck pain”, but noted that additional research was still needed on the subject.

The athletes, however, swear by it. Alexander Naddour, a do-it-yourself cupper thanks to a kit he bought for $15 on Amazon, was sporting the purple dots during competition Saturday in Rio.

“That’s been the secret that I have had through this year that keeps me healthy”, the gymnast told USA Today about cupping.

“I feel like every year at the big championship meets, my stroke just feels as good as it ever has”, she said. “It’s been awesome coming back here and just kind of accepting the expectations I have now, and knowing that’s just to do my best”.