At the 2016 Summer Olympics, Michael Phelps added to the collection of medals that make him "the most decorated Olympian of all time." But the medallions hanging around his neck weren't the only "decorations" that generated attention. The media and public also became fascinated by the tennis ball-sized red circles on his upper back and shoulders.
These welts are the result of cupping, a technique dating back to ancient Greece (making it an appropriate topic during the Olympics) that is common practice in traditional Chinese medicine.1 Dry cupping involves the use of negative pressure to create a suctioning effect without any skin perforation.2 Wet cupping also uses skin suctioning, but with added superficial skin incisions to induce bleeding.3 Cups typically are left on the skin for 5-20 minutes, creating a circular-shaped ecchymosis, which may last for days or weeks. Increasing the time and/or pressure exacerbates the ecchymosis.2
Thanks to Phelps, an ancient technique seemed new again. And, in a cycle that's all too familiar, viewers became intrigued by some "sanctioned," never-before-seen performance enhancer that gets worldwide exposure on the Olympic stage. In 2000, it was Australian sprinter Cathy Freeman's hooded bodysuit. In 2008, it was multicolored kinesiology tape, the Rorschach-like patterns adorning the bodies of volleyball, basketball, and track athletes. Now in 2016, it's the dark circles evident of recent cupping treatments.
Such things naturally draw our attention. And since the top athletes in the world are using these treatments, credibility is inherent or implied, right?
Not always so.
Injury preventing and performance enhancing approaches that rapidly gain widespread popularity will always outpace scientific research. It takes years to systematically investigate the physiological effects of various stimuli with strong scientific methodology, data collection, and analysis, and determine if these interventions are appropriate, how they should be dosed, and who is most likely to respond.
Despite the long history of cupping therapy, there is a noted lack of published evidence supporting it as a treatment for musculoskeletal conditions or defining the mechanisms by which it may have therapeutic value. The suction created by the cup produces a tensile stress on the skin and underlying tissue, along with compressive forces underneath the rim of the cup. These tensile stresses are thought to cause dilation and rupture of the superficial capillaries, creating the reddish-colored circles.2 This may reduce discomfort in the target tissues by stimulating inhibitory neural pathways.4 In this way, cupping may create a "counter irritation" effect that temporarily increases pressure pain thresholds.5,6 Additionally, altered local metabolic activity may contribute to this effect.7 However, these potential mechanisms of action are speculative and have not been thoroughly investigated.
Recent research published in journals of complementary and alternative medicine report that cupping may be beneficial for low back and neck pain,6,8-10 carpal tunnel syndrome,11 and knee osteoarthritis.12 At face value, these results appear quite promising, but they should be appropriately tempered due to the studies' methodologies.13 In each of these investigations, the comparison group received either no treatment or minimal intervention such as the single application of a heating pad.11 Without a true control group that mimics the potential psychological stimulus of a unique and impressive intervention such as cupping, we cannot differentiate true physiological alterations from placebo effect.14
When hundredths of a second are the difference between gold and silver (Phelps won the 200m butterfly by 0.04 second), athletes are looking for any potential real or perceived advantage and often explore alternative approaches. However, this is not done in lieu of the proven standards. Indeed, Phelps and his teammates are privy to round-the-clock medical attention from a team of sports medicine experts, including physical therapists. Olympic athletes regularly receive care that is well supported by strong scientific and clinical evidence. Evidence-based physical therapist treatment for musculoskeletal shoulder dysfunction involves therapeutic exercise,15,16 manual therapy,17 and movement and postural education.18
It's easy to understand why the media and public became fixated on Phelps' use of cupping—the welts were impossible to ignore. But while cupping is an adjunctive treatment that may, through currently unclear physiological or psychological means, have a short-term effect, we must be cautious that the general population doesn't see cupping as a silver-bullet treatment for musculoskeletal conditions.
Olympic athletes might include cupping as part of their extensive physical and mental maintenance to train and compete at maximum capacity, but an underlying theme of the Choosing Wisely campaign is the benefit of active therapy over passive treatments: www.choosingwisely.org/societies/american-physical-therapy-association/. As physical therapists, we want to maintain our position as evidence-based experts in the restoration, maintenance, and promotion of optimal physical function. To do so we must continue to uphold the value of well-established and rigorously investigated interventions in the face of the latest fascination in sports medicine.