Cupping, ah, the cupping!
Thanks for Michael Phelps and other decorated Olympians at the Rio Olympics, cupping is grabbing the world's attention.
But what is it, how does it work, and does it work?
Cupping, a manual modality that was found in both traditional Oriental and Occidental medicines, entails burning alcohol inside of glass cup (or a jar) to create vacuum and thus suction and then quickly placing the cup's open against the body, which then allows the cup to attach to the body through the suction created by the vacuum. The suction pulls the skin and muscles up, and in the process attempts to relax the muscles by creating space between the tight muscle fibers. Think of it as a reverse massage. In massage, the practitioner applies downward mechanical pressure, through fingers, palms, elbow, etc., to "break" up tight muscles. The strong suction created by the vacuum essentially does the same thing. The difference is that massage pushes while cupping pulls. Modern cupping devices has specially designed valves to allow the practitioners to pump out the air instead of burning off the air to create the suction. And it makes it easier for anyone to apply this modality easily and safely anywhere.
The cups may remain stationery, as seen in Michael Phelps' case, and they stay there for around 20 minutes. The tighter the muscles, the stronger the weld marks will be because tight muscles are less pliable and yielding. As a result, they resist getting pulled up by the suction, and that means there is a lot more of capillary breakage between the skin and tight muscle, which results in the red weld marks. My preferred cupping strategy is the rolling cupping, meaning that I actually move the cup along the muscle fibers to effect additional push/pull actions - I am massaging the muscles with cups!
Cups work best in flat surfaces, for obvious reasons, and areas where the muscles layers are relatively shallow. So, upper and middle back are the most common application areas for cupping.