Some strange circular bruises appearing on the back of Olympic medalist Michael Phelps had everyone asking what was causing his injuries—in reality, they're signs that he's been trying an ancient practice known as "cupping" to get some relief from neck and back pain. What is this strange practice? More importantly, is it any good? Here is what you should know:

What is cupping?

Cupping has its roots in Egypt, Greece, and China and it's a relatively simple procedure that takes heated cups and applies them directly to the skin of the patient above the area where his neck or back hurts. The heat helps create a firm suction between the cups and the patient's skin. As the heat dissipates, the skin gets sucked up into the cup ever so slightly. The cups are left in place for 5-10 minutes at a time before being removed.

It's believed that cupping lifts the skin, opening the pores, stimulating blood flow, and bringing healing doses of oxygen to the sections of the body that most badly need it. A lot of people believe that it's effective at reducing their back and neck pain, aside from Michael Phelps and a host of other Olympic athletes. Major League Baseball players, like Danny Duffy and Ian Kennedy, have used it for years. Dr. Ara Suppiah, the doctor for the European Ryder Cup golf team has also recommended cupping. 

Does it work?

According to those who swear by it, it works great. However, nobody seems to know exactly how it effects its cure. Explanations of its method of action include not only the idea that it allows increased blood circulation, but also that it trips the body's natural pain inhibitors. Another theory is that it works similar to acupuncture or acupressure, by stimulating some of the same points.

Despite the fact that nobody seems to know why it works, several studies indicate that the practice is generally safe and may have some actual benefit for the control of back pain and other conditions, especially if combined with other treatments, like acupuncture and conventional Western medications.

Should you try it?

If you suffer from back or neck pain due to a chronic condition and you've had trouble finding an effective treatment, cupping may be something that you want to try, as long as you talk the procedure over with your regular treating physician. Since it's non-invasive and doesn't require the use of narcotics or other drugs, it's generally pretty safe for most people. However, your physician may have some concerns about the practice if you've ever suffered from a DVT (blood clot) or you have any sort of skin condition that could cause breaks or tears in your epidermal layer that could let in infection.

Speak with a doctor about other alternative methods for neck pain relief if they interest you.