By Lara Rosenbaum

Thoracic outlet syndrome (TOS) is the constriction of the nerves and blood supply to your arms and hands. When it strikes, it can take weeks and even months to reverse. Here are some tips on how to keep it from sidelining your workouts from Rick Mehaffy, DC, director of Peninsula RSI (repetitive strain injuries), in Redwood City, California.

Q. What causes TOS?

A. “The neck and chest muscles shorten in response to static muscle contraction,” says Mehaffy. “It happens whenever your focus is forward and your arms are in front of you for hours at a time, like when you’re using a computer, or if your muscles are imbalanced, consistently pulling your shoulders forward. The constant contraction can restrict the thoracic outlet, through which all the nerves and blood to your arms and hands pass.”

Q. What are the most common signs?

A. “Most often, dull pain in arms, and possibly numbness and tingling in hands and fingers. Sometimes arms also feel heavy and weak – like they’re not attached,” Mehaffy says. “A way to differentiate TOS from Carpal Tunnel Syndrome (CTS) is to note the numbness: CTS causes numbness in the thumb, index and/or middle fingers, and sometimes part of the ring finger. But the whole hand? Pinky? Above the wrist? Then it’s likely TOS or another RSI.”

Q. How can active women prevent it?

A. “Balance strength training to work rhomboids and lats, and be sure to stretch your neck and pecs,” Mehaffy says. “Yoga is also great to add to a fitness routine for people diagnosed with TOS because lengthening of the muscles is the ultimate solution to most cases of this.”

Photography: Cory Sorenson, Model: Jamie Ford
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