Real reason why some Olympic athletes have dark circles on their backs

The 2024 Paris Games commenced last Friday and, since then, we've been treated to a load of impressive sporting performances, a heap of teary interviews and - of course - a whole bunch of Olympic Village drama.

And it seems the sport which seems to be getting the most attention right now is swimming.

We've already seen Matt Richards convinced he’d been wrongly denied gold before realising an 'excruciating' reality, Ana Carolina Vieira sent home after breaking a major rule with her boyfriend and Arno Kamminga's trunks leaving viewers in disbelief over an unfortunate optical illusion but the latest Olympics hype is all about the dark circles we've seen time and time again on swimmers' backs.

Why do so many Olympians sport these perfectly round bruises? (OLI SCARFF / Contributor / Getty Images)

What are the dark circles on athletes' backs?

Now, you may have seen such athletes covered in perfectly round bruises across their back and shoulders.

Well, the official television network covering the Olympics, Eurosport, has explained that these 'purple, pepperoni-sized circle' are not due to athletes falling asleep on their medals but actually the result of an ancient massage therapy.

Now, the method is believed to have its roots in the Middle East and Asian cultures and reportedly dates back to a whopping 3,000 years ago.

However, it was only in 2016 at the Rio Games when Michael Phelps - AKA the most decorated Olympian of all time with a total of 28 medals - brought this age-old practice into the mainstream.

Michael Phelps helped popularise the technique. (Amin Mohammad Jamali / Contributor / Getty Images)

The ancient technique, known as cupping, is actually a form of acupuncture therapy done by placing warm, round cups on the skin for several minutes to create suction.

It's actually a fairly common massage therapy for athletes across all levels as well as celebrities.

In short, cupping is used for pain relief and is believed to relieve muscle tension, increase blood circulation, enhance the immune system and eliminate toxins.

Phelps explained at the time why he opted for the treatment on his shoulder.

"That’s where I usually hurt the most [and] I’ve done it before meets, pretty much every meet I go to," he said.

"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."

The ancient massage therapy is used as pain relief. (Al Bello / Staff / Getty Images)

How effective is cupping?

According to Harvard Health, a 2023 review found the practice 'might provide some relief for a number of musculoskeletal and sports-related conditions', however, 'quality of the evidence was limited'.

While a review the year prior found that 'wet (but not dry) cupping was effective for low back pain'.

Harvard Health states: "Most experts agree that cupping is safe. As long as those treated don't mind the circular discolorations (which fade over a number of days or weeks), side effects tend to be limited to the pinch experienced during skin suction.

"It's quite unusual that cupping causes any serious problems (though, rarely, skin infections have been reported)."