How Did Michael Phelps Get Those Scary Bruises on His Skin?

NBC Olympics

Some Olympic athletes, including 19-time gold medalist Michael Phelps, have taken to a traditional Chinese-medicine treatment called cupping — a method of applying suction to targeted spots for health benefits — that often leaves athletes with dark red circles on their skin.

Phelps' treatment can be seen clearly in footage from the 4x100m freestyle relay, which saw the swimmer win his 19th career Olympic gold medal in Rio de Janeiro. Other cupping devotees include Team USA gymnast Alex Naddour, Belarusian Olympic swimmer Pavel Sankovich and former U.S. Olympic swimmer Natalie Coughlin.

NBC Olympics

What Is Cupping and How Does It Work?

One common method of cupping uses small glass cups or bamboo jars that are swabbed with rubbing alcohol and then set on fire, according to the Pacific College of Oriental Medicine, which has locations in New York, San Diego and Chicago. The flaming cup is then placed against the skin to create a suction (ouch).

'Why?' do you ask would athletes inflict themselves with such pain? Well, that suction is said to help treat a variety of ailments, including the muscle pain that athletes experience. But one of the side effects isn't so pretty — the noticeable marks left behind from the burns and bruising.

Thanks @arschmitty for my cupping today!!! #mpswim #mp 📷 @chasekalisz

A photo posted by Michael Phelps (@m_phelps00) on

So the question now becomes: Are the health benefits of this traditional Chinese practice are worth the tracking marks? Some experts seem to think so.

"The suction and negative pressure provided by cupping can loosen muscles, encourage blood flow, and sedate the nervous system (which makes it an excellent treatment for high blood pressure)," according to PCOM.

PCOM reports that cupping is used to relieve back and neck pains, stiff muscles, anxiety, fatigue, migraines, rheumatism and cellulite.

"For weight loss and cellulite treatments, oil is first applied to the skin, and then the cups are moved up and down the surrounding area," PCOM notes.

Gee, I hope my #GoldenGoggles dress is open-backed.

A photo posted by Natalie Coughlin (@nataliecoughlin) on

Cupping Isn't Just for Olympians

The practice isn't limited to Olympic stars, though: Academy Award-winning actress Gwyneth Paltrow caused a stir in 2004 with her own cupping marks. She had turned to the treatment reportedly to help with back pain. Actress Jennifer Aniston is also a fan, and singer Justin Bieber has also tried the therapy.

A common reason people turn to cupping is to release toxins from the muscles, allowing the muscles to relax, which may alleviate pain.

This kinda Saturday morning. Cupping is a great recovery tool #cannotwalk#everydayislegday

A photo posted by Pavel Sankovich (@pavelsankovich) on

What Do YOU Think?

Have you tried cupping? What about acupuncture or another form of traditional Chinese medicine? If so, what was your experience like? Let us know in the comments!