Cupping: The ancient Chinese therapy that Rio Olympics athletes are loving now

This is why you have seen the purple dots on Olympian, Micheal Phelps.

Everyone’s talking about cupping, a therapy that some Olympic athletes competing in Rio have been joined in. It caught people’s attention this week because the therapy often leaves round marks that look like bruises on the skin, but it’s certainly not new. The ancient practice has been used in Chinese medicine for thousands of years as a way to treat pain, muscle stiffness and even respiratory issues.

One of the most notable athletes to sport the signature cupping marks is Michael Phelps. Other athletes, including swimmer Natalie Coughlin have also embraced the practice.

So how does cupping work? Either heat or air is used to create a suction in special cups that are placed on the body. The vacuum created then pulls the skin and blood vessels in toward the cup, which is why they can leave marks on the skin.

Cupping is thought to pull blood to a certain area, and improve circulation and loosen up muscles and joints. There’s also some suggestion that it has anti-inflammatory effects. In the U.S. it is sometimes used in addition to acupuncture or massage. A specialist can apply the cups, though some athletes say they are doing it themselves, USA Today reports,

There is a difference between how cupping is practiced in traditional Chinese medicine and how it is used in Western medicine

In traditional Chinese medicine, the theory is that cupping can influence the flow of energy or “qi” through the body.. If someone’s flow is blocked or stagnant, a practitioner might use cupping to impact the flow. Western practitioners may focus more on what the therapy might be doing to muscles or blood flow.

Some question whether there’s enough clinical evidence to say cupping is definitely effective—though it has been studied.

A 2010 review of 550 clinical studies, including 73 randomized controlled trials—which are considered the gold-standard study in the science community— concluded that the “majority of studies show potential benefit on pain conditions, herpes zoster and other diseases.” None of the studies reported serious bad health outcomes from the practice. Another 2014 review of 16 studies with 921 people reported short-term pain reduction from cupping.