For many of us, bra shopping is roughly as fun as a colonoscopy. But a new study offers one good reason to stick with it: The right sports bra may help make us better runners.
Nearly 3 in 4 women experience breast pain while running, often due to a combination of larger breasts and an ill-fitting or unsupportive sports bra, researchers note in a new study published in Frontiers in Sports and Active Living.
A good sports bra can reduce breast pain, the researchers found, but its benefits go beyond that: A supportive, well-fitting bra can also change how much the knees flex during running, improving performance.
“The human body typically optimizes cyclic movement patterns for walking and running toward metabolic efficiency,” says lead study author Douglas Powell, PhD, director of the Breast Biomechanics Research Center at the University of Memphis in Tennessee. “By removing or reducing the constraint of breast motion, the neuromuscular system can perform in a more metabolically efficient manner.”
The new study complements research published last year in the same journal that found that supportive, well-fitting sports bras can improve running performance by 7 percent by helping runners use oxygen more efficiently.
Study Subjects Ran With Low-Support Bras, High-Support Bras, and Bare-Chested
For the new research, researchers wanted to see how reducing breast motion with a more supportive bra during running might affect a biomechanical measurement known as knee joint stiffness. While the issue remains under investigation, a body of previous research has suggested that the stiffer the knee joint, the greater a person’s running efficiency.
Researchers had twelve recreational runners ranging in age from 18 to 35 years old who wore bra cups in size B, C, or D get professional bra fittings for two different sports bras: one with high support that allowed less breast movement and one with less support. Each participant then ran on a treadmill three times, once with each of the different bras and once bare-chested.
While women ran, scientists used motion capture cameras and 3D software to calculate knee joint stiffness and the amount of breast movement.
With a low-support bra, the runners had 2 percent more knee joint stiffness than they did when they ran bare-chested, the study found. And with a high-support bra, the runners had 5 percent more knee joint stiffness than when they were bare-chested.
A Good Sports Bra Matters for Many Reasons
One limitation of the study is that it’s too small to be representative of all recreational runners, the study team notes. It’s also unclear whether the results would apply to women who have avoided running due to breast pain but want to try again with a more supportive bra.
Even so, the results should serve as a reminder to female runners to think carefully about how their bra might impact their workout experience, says Nicola Brown, an associate professor of female health and performance at St Mary’s University Twickenham in England.
“If breasts are not appropriately supported they can move independently from the body during exercise,” says Brown, who wasn’t involved in the new study. “This movement can alter running mechanics, muscle activity, breathing frequency, perceptions of effort, and can deter women from exercising due to pain or embarrassment.”
Tips on How to Buy a Sports Bra That Fits Right
To get a good fit on a sports bra, women should look for a firm band under the breasts that sits level around the body without any gaping or puckering of the cups or breasts spilling out of the cups, Brown advises. It’s easier to get a good fit when it’s possible to adjust both the band and the straps, Brown adds.
“It is a good idea to try on your sports bra and have a jump around in the fitting room to check if it is supportive enough and feels comfortable,” Brown says.
And even when you find the perfect fit, it’s important to know the best sports bra won’t keep its shape forever, Brown adds. “If you feel your breasts moving excessively during exercise, or experience any pain or discomfort during activity this suggests that your sports bra may not fit properly or may need replacing.”