Rematch in Rio: Phelps, Le Clos face off in 200 fly

Chad was a full second behind Michael, and in the Olympic pool, a second is more like a minute for the rest of us. Cupping is an ancient technique alleged to improve circulation and help muscles heal.

They were torn between watching Michael Phelps compete from their seats in the arena, or take their chances to catch a glimpse as he worked his way through the scrum.

Cupping involves placing a vacuum cup over the skin, which is then sucked upwards in a domed shape – leaving the trademark circular bruises. And it’s not just sports stars – you may even remember seeing similar marks on Gwyneth Paltrow’s back in 2004 (on the red carpet, no less), or posted on Instagram by Lena Dunham. I’m not going to lie here – I skipped the “Phelps in Rio cupping” headlines because it sounded vaguely like something his speedo was doing (I know, my mind is always in the gutter). “I just asked for a little cupping yesterday because I was sore”.

Dr Ravalia’s clinic charges around £50 for a session of wet cupping that lasts about an hour.

But Caulfied says you are a lot better off not that spending that money.

“If he feels like he feels better”, Hamilton said, “that’s never a bad thing”. “He said I was his hero, and then he was calling me out”.

Very little evidence has come up in scientific literature to support the practice, but it’s important to note that little has been found to disprove it either. A 2010 review of 550 clinical studies on cupping did find that there is a potential benefit on pain conditions, cough, asthma and other diseases. It also found no serious adverse effects of cupping.

The stirring victory – televised in prime time back home in the United States – put Phelps back on the podium and thrust cupping therapy into the spotlight.

The British Acupuncture Council say cupping is not painful but they warn that the hot cups can cause mild burns on rare occasions. But in the meantime, you can at least get the same haircut as him.

“It’s not like they cover it up – it’s a bit of a personal identity”, Caulfield said.