Rio 2016: What Are The Large Circular Bruises On Michael Phelps’s Back? ‘Cupping’ Explained

If you have been following swimmer Michael Phelps‘s triumphant return to the Olympic pool, you may have noticed a strange collection of circular bruises spread across the 19-medal winning athlete’s back. You might be more surprised to learn that the marks are intentional, even therapeutic. The dozen-or-so circular bruise on Phelps’s back are the result of cupping therapy, an ancient Chinese treatment thousands of year old.

Michael Phelps’s Large Circular Bruises

Designed to alleviate pain and aid the recovery process, the treatment takes five to ten minutes and originally was performed by lighting flammable materials in glass jars. Once the flame was extinguished, placing the jars top down on the skin creates a vacuum, pulling the skin into the jar and causing a slight pinching sensation. Which machine being used now to replace the flame, the aim is to push the skin away from the muscle and bone, allowing blood vessels to expand and increase blood flow to the area.

While Western medicine is critical of the treatments effectiveness, some say the placebo effect of cupping might be enough to aid the athlete. Phelps hasn’t been the only athlete on team USA to use the treatment either. Gymnast Alex Naddour has also been using cupping to alleviate shoulder pain: