Have you ever seen those round marks on athletes? Rows of dark purple circles on someone’s back, like they’ve been hit.

That’s not from getting hit. That’s from cupping.

What is cupping? You take a glass jar, heat the air inside with a small flame, and place it on the skin. When the air inside cools down, it contracts and creates suction, pulling the skin and the muscle underneath upward. After about fifteen minutes, you remove the jar, and a round mark is left on the skin.

That mark is not a bruise. Bruises come from blunt force breaking blood vessels. Cupping marks come from suction pulling things from deep inside your body up to the surface. The darker the mark, the more “stuck” that area was.

Why do this? Because TCM believes that many kinds of pain and discomfort come from “cold,” “dampness,” and “stagnation” stuck in your muscles. Cupping acts like a vacuum cleaner, sucking those unwanted things to the surface so your body can clear them out.

Someone with stiff shoulders will feel much looser after cupping. It’s not psychological — you’re physically pulling tight muscles open and sucking out stuck things.

The marks usually disappear on their own within three to seven days. No scars. The color fades from dark purple to red to yellow, then gone. Darker marks mean the problem has been there longer.

Cupping isn’t for every illness. It works best for muscle pain, stiff neck and shoulders, and the early stages of a cold when your back feels cold and tight. After cupping, avoid getting the marked areas wet for a few hours. Keep warm. Drink plenty of warm water to help your body flush things out.

If you see someone with round marks on their back at the gym or in the locker room, don’t get the wrong idea. They’re not injured. They just gave their body a deep cleaning.