A Las Vegas massage therapist demonstrates Michael Phelps’ cupping regimen — VIDEO

After the second day of the Olympics, Michael Phelps waltzed up to the starting blocks and revealed dark purple spots on his shoulders.

Twitter lit up asking what the marks could be and news organzations sought to find the answer.

We found IMR Massage Las Vegas and its owner Elliott Reed, who specializes in cupping therapy. It’s the same treatment Phelps used and resulted in the dark marks along his back.

Reed and his client Erica Vickery showed us step-by-step what cupping therapy is and what it does for the body.