On Sunday night, figure skater Mirai Nagasu made history as she became the first American woman to land a triple axel at the Pyeongchang Winter Olympics. Landing the extremely difficult jump after making three-and-a-half revolutions in the air earned her a bronze medal and 137.53 points, a near-perfect score and a personal best for Nagasu. Amid ecstatic celebration both on the ice and the internet, fans could not help but notice a tattoo-like mark on her inner thigh beneath her red dress.

Closer inspection revealed it was a strip of kinesiology tape, as KT Tape, the official tape licensee for the United States and Olympic and Paralympic teams, confirmed on Twitter in response to puzzled queries about Mirai’s strange tattoo. KT Tape’s PRO USA tape is emblazoned with the letters USA in large, bold type, adding to its tattoo-like looks.

But the the tape’s purpose has nothing to do with aesthetics. Kinesiology tape is meant to treat pain caused by muscle strain and provide extra support to overworked muscles. In Nagasu’s case, the tape was likely meant to support muscles in her leg and groin, which are crucial to explosive jumps like the triple axel.

The tape is widely used by Olympic athletes both on and off the ice. In an interview with NBC in 2016, during the Summer Olympics in Rio de Janeiro, Dr. Heather Linden of the U.S. Olympic Committee’s Sports Medicine Division explained that kinesiology tape seems to improve athlete posture, reduce inflammation, and lift the top layer of the skin, which “helps the circulation and lymphatic drainage.”

When a muscle is overworked or injured, it swells up as the body’s immune system floods the area with blood and lymphatic fluids to repair the damage. This inflammation can be painful and interfere with an athlete’s performance, so cutting down the swelling immediately is key. Kinesiology tape is thought to pull up on the skin so it doesn’t weigh down these already-enlarged areas, allowing the fluids to drain more rapidly and freely, like taking your foot off a garden hose.

But, as Linden pointed out in her interview, there isn’t actually much science to back up the use of kinesiology tape. “All of it more is an athlete feedback, athlete preference,” she said. That’s not to say it doesn’t do what it’s purported to do; it could just be that clinicians simply haven’t done the studies or found it unnecessary to do so, seeing as professional athletes from the NBA’s James Harden to David Beckham have already turned taping into a regular practice.

After all, who can argue with low-risk intervention that makes an athlete feel good enough to land a groundbreaking triple axel?