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The Real Story Behind Why Breasts Bounce, Banner Image

The Real Story Behind Why Breasts Bounce

Updated 6 April 2022.

It is a fact that every woman knows; our breasts bounce when we move around. The more we move the more our boobs bounce! Anyone who’s run after a train or up and down some stairs knows this all too well. Especially if you are only wearing an ordinary everyday bra. But why do they bounce so much and why aren’t they given better natural support to hold their place?

Breasts are the body part most affected by gravity, given there is little natural support to hold them in place. They are primarily made of mammary glands and soft tissue with the only support offered by the Cooper’s ligaments. These can be easily damaged by excessive breast movement, leading to breast pain.

There are no muscles within the breast to help keep them in place. With the chest muscles underneath offering little to no natural support to hold your breasts and keep them from moving around. See our ‘Why Wear a Sports Bra?’ page for a bit more info.

So why aren’t they given better natural support?

So why aren’t they given better natural support to hold them in place? In a nutshell, simply because they don’t need it. Evolution generally only does things for a benefit and there is no benefit in supporting the breasts (apart from looking good!)

I joke on this point, but some scientists believe that larger breasts and butts are our evolutionary way of attracting a mate. Which is why our breasts continue to get bigger, and unfortunately our butts! Women generally weren’t required to run (they were gatherers after all) so expending energy supporting our breasts wasn’t an evolutionary necessity.

So, evolution put us here. With an average breast weight of approximately 1.5kgs (depending on size of course) and growing, the amount of boob bounce is getting greater. On average, a woman’s breasts move 9cm with every step taken. This isn’t just up and down but also side to side.

Break into a run and this breast movement can increase to 15cm with every stride! Wow. I don’t know about you, but this fact makes me want to wear every sports bra I own before going for my next run. To put this into perspective, if a D-cup size woman runs for one kilometre, taking 1000 steps, her boobs will have also traveled as much as 150m. Ouch!

Unfortunately, as breasts are getting bigger, it also opens us up to a multitude of problems. From chronic breast pain due to movement to lower back pain as our bodies strain to support the weight of our breasts. This is why more and more women are opting to wear sports bras because of the added support and comfort they offer.

The Real Story Behind Why Breasts Bounce

How do Our Breasts Move?

But aside from the evolutionary background of boob bounces, another oddity of the breast movement world is that each boob has its own movement pattern. Often moving independently in a ‘figure of eight’ pattern. Unfortunately, the older we get, the further our boobs bounce and travel.

A study carried out by Portsmouth University’s Research Group in Breast Health – which used hi-tech sensors and 3D scanning to analyse the motion of breasts – monitored the boobs of two sets of women, aged 18 to 25 and 45 to 65, during brisk walks. Researchers discovered that while the younger women’s breasts mainly moved up and down, the older group’s bosoms moved more in all directions.

Professor Joanna Scurr, an expert in biomechanics of breasts, said “In all women, their right and left boobs move differently, depending on mass and how elastic they are. However, in older women, there is more movement in both breasts, probably because the supporting structures are not as strong. You will tend to see a more U-shaped swing.”

Our relatively recent obsession with running and exercise (our only gathering is getting the washing in and picking up toys!) combined with ever-increasing breast size has caused the bounce problem and in relation, breast pain and back pain. So, what is the solution?

Finding a good bra that offers impressive support, regardless of your breast or cup size. However, we all know that women come in all shapes and sizes. And with that, breasts also come in various cup sizes. Which may make choosing the appropriate bra fit much more challenging.

To ensure the perfect bra fit the best option for you is to find a great sports bra that can effectively keep your breasts from moving from side to side. Find the perfect sports bra for you and you’ll go a long way to eliminating the dreaded breast bounce for good.

With new technologies and new complementary products like the PINKCLOVER Breastband the days of having to wear two or more sports bras are well and truly behind us all.

Yours in support.

Amy x

Amy Jaffers

Amy is the face behind Sports Bras Direct, Australia’s largest sports bra website. She's a mother of two, outdoors lover and sports bra expert. Her life mission is to help active women get the support they need as well as assisting women in need through her charitable donations.

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