This is why Michael Phelps has round marks on his back at Rio

Aug 2, 2016; Rio de Janeiro, BRAZIL; Michael Phelps during a training section at the Olympic Aquatics Centre prior to the start of the Rio 2016 Olympic Games.
Rob Schumacher-USA TODAY Sports

Michael Phelps will be on your TV screen a lot over the next week. When he’s on the screen before a race, you’ll probably notice some circular red marks on his back and around his right shoulder. Here’s why he has them.

Phelps, who some call the greatest Olympian of all-time, has adopted a “cupping” strategy that has become popular among swimmers and other athletes.

“Cupping” is used to help blood flow in problematic areas for swimmers. It uses suction cups to help improve blood flow for muscles that have become sore.

Here’s how NBC describes it:

Basically, cupping involves a cup attached to a pump. Athletes put the cup on their skin and create suction with the pump. Some say the technique increases blood flow and helps a person’s sore muscles heal.

According to WebMD, cupping therapy “dates back to ancient Egyptian, Chinese, and Middle Eastern cultures.”

Phelps apparently uses a version of the therapy that involves heat to create suction (it was even featured in his Under Armor ad announcing his return to competitive swimming).

The cupping form of therapy for sore muscles typically gives athletes visible bruises, as shown better here:

Here’s what Phelps’ looked like before his race this evening.

Here’s Phelps’ Olympic schedule:

Sunday, Aug. 7: 4x100m freestyle relay final (10:52 p.m.)

Monday, Aug. 8: 200m butterfly prelims (12:34 p.m.), semifinals (10:10 p.m.)

Tuesday, Aug. 9: 200m butterfly final (9:28 p.m.), 4x200m freestyle relay final (10:38 p.m.)

Wednesday, Aug. 10: 200m individual medley prelims (1:09 p.m.), semifinals (10:29 p.m.)

Thursday, Aug. 11: 100m butterfly prelims (1:16 p.m.), semifinals (10:34 p.m.), 200m IM final (10:01 p.m.)

Friday, Aug. 12: 100m butterfly final (9:12 p.m.)

Saturday, Aug. 13: 4×100 medley relay final (9:49 p.m.)

Phelps has won 22 Olympic medals – 18 gold medals, two silver medals and two bronze medals.

More from College Spun: