From Mic:

Does cupping work? The therapy practice used by Michael Phelps and more has a major following

Cupping therapy has been westernized for use in the physical therapy setting. Celebrity physical therapist Dr. Karena Wu utilizes this modality with her clients to promote increased range of motion, fluid mobility, and reduced perception of pain. This modality is the only decompressive therapy that lifts up on the soft tissues to help loosen you up. The western application has the tissues move under the cups. To read more about this therapy, click here.

Full article link: https://www.mic.com/p/does-cupping-work-the-therapy-practice-used-by-michael-phelps-more-has-a-major-following-17948213