As the swimming competitions go on at the 2020 Tokyo Olympic Games, athletes from across the world have shown off their bodies covered in strange-looking dark circles as they throw themselves into the races.
It's certainly not the first time the big dark blotches have appeared on the backs of Olympic athletes, but after being seen on the backs of both Japanese swimmer Akira Namba and Team Australia's Kyle Chalmers, people online have bene wanting to know more.
In 2016, the dots were featured on gold medalist Michael Phelp's back as he raced through the water, while Team USA gymnast Alex Naddour had them on her shoulders.
Well, these marks come from a process known as cupping! It's an ancient therapy with roots in Middle Eastern and Asian cultures and the practice benefits blood circulation, relieves muscle tension, and promotes cell repair... even though scientific evidence is a little lacking.
So, what exactly is it? Cupping creates suction on the skin using glass, ceramic, bamboo, or plastic cups, leading to a negative pressure being created by attaching a suction device to the cup, drawing out any air, decompressing the muscles, and "promoting blood flow."
This in turn is known to speed up the body's healing process.
As per The Independent, the roots of cupping date back to the ancient Greek physician Hippocrates, who practiced in 400 BC, using cups to treat internal disease.
So the marks on the back of the extraordinary athletes are left due to capillaries just below the surface of their skin rupturing, which creates the image of bruising under the skin.
At the time that Phelps had been "cupped", he spoke to Sky Sports and said: "That's [my shoulder] where I usually hurt the most and I've done it before meets, pretty much every meet I go to. I just asked for a little 'cupping' yesterday because I was sore and the trainer hit me pretty hard with one and left a couple of bruises."
However, Gwenyth Paltrow has been using the treatment before athletes at the Olympics.
"Suffice it to say, we at Goop have been into cupping since – well before Michael Phelps won his first gold medal," she writes on the Goop website.
In 2004, she sported similar red blotches on her back while attending a film premiere in New York City.
WXYZ-TV Detroit | Channel 7 asked Dr. Nandi if cupping actually works.
"I would have to say yes and no," the doctor replied. "Most of the benefits of cupping are. a result of the placebo effects but studies have shown that it can be effective."
He also advises that if anyone were to try the process of cupping, it should be carried out by a trained health professional and you should understand the risks.