Rio 2016 Olympics: Stars, stripes… and spots? USA’s cupping technique as used by Michael Phelps

Updated 08/08/2016 at 10:00 GMT

Team USA’s Michael Phelps stormed to his 19th Olympic gold in the 4x100m freestyle relay on Sunday, but keen-eyed viewers were left asking why the all-time great was covered in spots on his back and shoulder.

Michael Phelps sporting marks on his shoulder at Rio 2016

Image credit: Reuters

In a nutshell, the blood-coloured spots are a side-effect of cupping, a healing technique which is said to increase blood flow and help sore muscles to recover.

Cupping essentially involves a series of cups and pumps, which are attached to the body before suction is created, as shown by Belarusian swimmer Pavel Sankovich.

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Although it is seen as an ancient form of therapy, it appears Team USA have long adopted this treatment, with swimmer and 12-time Olympic medallist Natalie Coughlin sporting the marks over two years ago.

Current US gymnast Alex Naddour displayed the mark on a recent Instagram post, proving it's not just swimmers who are using this recovery aid.

The bruises can last for up to two weeks according to The State News, who investigated Michigan State University's use of cupping.

Whether it catches on remains to be seen, but expect these spots to be dotted around numerous athletes before the closing ceremony.

Rio 2016