Compression down to a science

AP Photo/David J. Phillip

Compression sleeves, like those worn by Allyson Felix above, are designed to help reduce muscle stress.

Athletes from NBA players to Olympians are squeezing themselves into compression clothing these days, and not just for performance -- they're wearing it for recovery, too.

"It really helps with endurance and muscle fatigue," said paddleboarder Jenny Kalmbach, who is sponsored by Australian compression-wear company 2XU. "I wear it during all my races and training, but more often for recovery. The added benefit, for me, is it also works as sun protection."

Seven-time Ironman finisher Marni Sumbal has been wearing graduated compression socks, calf sleeves and tri shorts for five years. "I recover more quickly post-workout when I wear compression," she said.

FABRICE COFFRINI/AFP/Getty Images

Alpine skier Larisa Yurkiw started wearing compression clothing after a 2009 knee injury.

So just how does it work?

"Compression is a mechanical feature of the garment. It's the amount of Lycra or spandex that's woven into the garment and how the garment is constructed that functions this way," said Dr. William Kraemer, professor of kinesiology at the Neag School of Education at the University of Connecticut.

Kicking up venous blood flow -- or encouraging blood to return back to the heart after circu-lating through the body (also known as oxygenation of the blood) -- is the main reason people wear compression clothing. Muscle containment is another purpose cited by manufacturers. Compression is measured in millimeters of mercury (mmHg), just the way a blood pressure cuff measures it at the doctor's office.

"If given enough compression, depending on the garment's construction and purpose, anywhere from 15 to 25mmHg, you can reduce oscillatory stress of the muscles as they hit the ground, say when jumping or running," said Kraemer, who performs his research at the Human Performance Laboratory at UConn.

"Compression assists in proprioception," or the body's ability to determine what its parts are doing at a given time, Kraemer said, "by interacting with the pressure receptors in the skin which receive sensory information that reports back to the brain.

"You need to have a certain percentage of Lycra in the fabric, about 24 to 28 percent, in order to get the desired effect on proprioception, encouraging oxygenation of the blood or mechanical support of the body."

Compression garments, generally speaking, are gradient, which means they are tightest at points farthest from the heart. For example, compression socks are closest fitting around the foot and ankle and become gradually looser going up the leg.

The benefits of compression aren't universally accepted. Robert Otto, a professor and director of the Human Performance Laboratory at Adelphi University, said that absent circulatory medical conditions, compression gear isn't necessary, that people who exercise are already enhancing the mechanisms that return blood to the heart.

"The body works so much better during exercise than at rest so the need for compression garments is really difficult to determine, and athletes generally have better circulation than the average person."

And experts do not always agree on what kind of compression is adequate, or even too much. Otto suggests that gradient compression greater than 20 mmHg in compression socks, commonly used for endurance activity, could be too much. "It could restrict blood flow," he said.

So for the everyday athlete, it's a good idea to check with a doctor before investing in compression wear to see if it's right for you and your activities. Many swear by it.

Neal Pire, a sports conditioning expert and fellow of the American College of Sports Medicine, said the runners he knows "won't run without it. If they say it works, it has a value, even if this is a placebo effect."

Alpine skier and Sochi Olympic athlete Larisa Yurkiw says she started wearing compression clothing after a 2009 knee injury: "Then I carried it over to everyday use. My physical trainer and my surgeon suggested the use of compression. I feel swollen and restricted in my knee joints when I forget to wear it for long periods of time; I always feel much more mobile when I wear it."

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