As if running weren’t challenging enough, large breasts can make it a full-on contact sport.

Thumping against your chest, weighing you down, and threatening to give you black eyes, graphic breast bouncing is more than embarrassing. It’s painful – and can prove detrimental to running performance, says sports physiotherapist Deirdre McGhee, a researcher with Breast Research Australia at the University of Wollongong.

Here, we explore the top three complaints of large-breasted runners everywhere – as well as how to ease the pain with some simple tricks and bra-fit guidelines.

1. Baby Got Back Pain

A pair of D-cup boobs weigh in at 6-10 kilograms. That’s more than enough to pull your body forward, force you into a hunched-over running posture, decrease your stride’s efficiency, and up your risk of injury, McGhee says.

If you haven’t noticed, pretty much the only thing keeping your breasts up during a run is your bra’s shoulder straps, which take a lot of weight. When straps are thin, the pressure can be so great they not only leave dents in your shoulders but hit the brachial plexus nerve group, causing numbness in the pinky fingers.

While you can’t reduce your breasts’ weight without a breast reduction, you can improve your body’s ability to remain erect, says Janet Hamilton, an exercise physiologist at Running Strong in Atlanta.

Upper and lower back exercises (think: pull-down and row variations) can help prevent the back fatigue and poor posture that can set in with longer running durations, Hamilton says. Exercising your core, which includes your lower and middle back, can help stabilise your spine, says Victoria Barnaby, an athlete with the Greater Boston Track Club and a CoachUp running coach. Focus on functional core strengthening exercises that work multiple muscles through several planes of motion, she says. Examples include the forearm plank with alternating leg raises, prone plank on a stability ball, Superman, bird-dog, side plank, and abdominal twists.

2. The Bounce Factor

How far your boobs bounce depends almost entirely on breast size and elasticity of the skin covering your breasts, says McGhee. However, skin tends to lose its elasticity with age and “excessive breast bouncing.” So, the more your breasts bounce, the more they will bounce during future runs.

How much do breasts bounce? Measuring the bounce of both bare and bra-covered breasts during treadmill workouts, McGhee found the average 38D moves about 13 centimetres from top to bottom during running. Small breasts bounce about seven centimetres, which can still be uncomfortable.

While they can’t completely eliminate bouncing, high-support bras can cut the range of motion in about half, McGhee says. (Check out tips on buying your best bra below.) The goal is for the breasts to move in unison with your torso and not bounce independently of one another.

3. Rubbed Raw

“Finding a sports bra that fits properly to your bust is the first step to prevent chafing,” says Barnaby. The less your bra moves during your run, the less it will rub. (Again, we’ve got tips for buying your best bra below.) However, the larger your breasts, the more difficult it can become to prevent any movement. She suggests using anti-chafing balms and creams on sensitive areas such as under your armpits.

If your running bra still rubs you raw, apply a thin strip of first-aid tape across the areas where you tend to chafe before starting your run, Hamilton says. Since tape can be an irritant, it’s best to try it during a short run before heading out on a 8-15km run, she says.

Wearing a sports bra that’s built with sweat-wicking materials can prevent skin irritations, which can develop into full-blown chafing, McGhee says. Bonus: You’ll have less breast sweat pooling under your nose.

How to Find Your Best Running Bra

“When first purchasing a sports bra, resist the urge to purchase online; go to a retailer to try on styles,” Barnaby says.

Look for bras with high-support elements such as molded cups, underwires, padded straps, and multiple hooks. McGhee recommends trying on as many bras as possible to find which ones keep the girls in place – without sacrificing too much comfort. “If a bra is not comfortable to wear walking and stretching, then don’t even think about hitting the road with it,” Barnaby says.

When trying on sports bras, though, don’t just go by the feel. McGhee recommends looking for these markers:

The Band: It should be made of wide elastic material so it can support your breasts without causing back bulges or riding up when you lift your arms. You should fasten the bra on the loosest hook so, as it ages and becomes looser, you can tighten the fit.

The Shoulder Straps: They should be wide and padded so they don’t dig into your shoulders.

The Cups: To limit movement, the cups must completely cover your breasts (without leaving any creases or gaps). Keep in mind your running bra cup size may be different from what you wear under your little black dress. That’s OK.

The Underwire: It should sit on your ribs so it doesn’t dig into your breasts or the tissue under your armpits.

The Front Band: The centre of the bra should sit on your breastbone, squarely between your breasts.

Meanwhile, if you’ve long since outgrown DD bras, you may need to look for a “crop top” compression bra for some double-bra layering, McGhee says.

She recommends first putting on a high-support bra with structured cups and an underwire and then layering it with a compression bra that will help hold everything in place. Again, with the compression bra, you’ll need to find a middle ground between “my breasts are all over the place” and “I feel like an encased sausage.”

After a few runs, chances are you’ll figure out the brands and styles that work best for your unique shape, Barnaby says. Once you find your can’t-run-without bra, write down its silhouette and style number. It’s the key to being able to buy online – or finding a similar bra should the brand discontinue the style. Either way, it’ll simplify the contain-the-girls process for future runs.

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