“Be not afraid of growing slowly, be afraid only of standing still.”
Chinese proverb
Fire cupping is a technique that uses heat to create a vacuum of suction to draw qi (energy) and oxygenated blood flow up to the surface. The cups release the tension of fascia around the muscles to facilitate tissue healing by improving circulation and removing toxins from the muscle layer. Using the meridians on the back, cupping relaxes the sinew so as to align the structure of the body to move qi into alignment.
Check out this article from Pacific College of Health and Science to learn more about the classical sense of cupping.