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Check out our stellar sports bras for running in 2023.

In the population as a whole, 50% of women experience breast pain, either during activity or through hormonal cycles. In a survey conducted in 2012 by the University of Portsmouth of female London Marathon runners, breast pain was experienced by 32% of them and 17% of the ladies said it actually affected their participation in sport. This is almost exclusively down to using a sports bra for running that is simply not up to task, that gives insufficient support or the dreaded chafe.

The good news: this is not something you have to put up with- here at KnockerLocker we have the know-how to guide you towards a sports bra for running that will work for you. Because let’s be honest, running is hard enough.

Sporting performance

Beyond the pain of an excessively bouncing bosom, it has been found that excessive breast movement actually affects performance. Female runners shorten their stride length by around 4cm to try and reduce the bounce. Over the course of a marathon that equates to an extra mile.

“Excessive breast movement causes women to shorten their running stride length by around 4cm”

Brogan Horler, university of portsmouth

What are my breasts made of?

Breasts are made of glandular tissue and fat with some strands of connective tissue (known as Cooper’s ligaments) running through. They are held up by nothing more than skin. WHATTTTT? I originally thought the Cooper’s ligaments were tough old fibrous bands- like the kind of ligaments that hold your joints together, that literally strapped your breasts onto your chest wall. But no, according to the University of Portsmouth Breast Health Research Group, this is not the case. Understanding this key feature of the anatomy helps you immediately realise why your breasts need significant support.

How big is big?

It is now recognised that more than 35% of women have what are deemed large or hypertrophic breasts. Large breasts are defined as breasts where each is over 700ml in volume. Hypertrophic breasts are greater than 1200ml each in volume. Just to put this in context- a rack of 700ml breasts would total up to be the equivalent of two loaves of white bread, 16 satsumas or a pair of 8 week old kittens. A pair of 1200ml breasts equates to 2 pineapples, one standard sized brick or 2 toasters.

It is difficult to equate these volumes exactly to bra sizes. Owing to differing back and cup sizes and breast shapes it is hard to be accurate. But hopefully the examples above give you a good idea. Whatever way you look at it, it’s a lot of weight to be held up by nothing more than skin. Unfortunately, large breasts do have negative health implications– they are associated with postural difficulties and musculoskeletal pain in shoulders, neck and back. Need a bigger bust sports bra?

woman wearing a Pure Lime sports bra for running

80% of women still wear the wrong bra size

Understanding breast anatomy also helps you understand why your breast size changes so readily- whether through hormonal cycles or weight change, the glands and fat content change accordingly and with that, your bra size. Just because you got measured 4 years ago- before you had a child, lost 2 stone and took up powerlifting, doesn’t mean that same fit still applies. Check out our fitting guide and bra size calculator to help you assess how your current bras are fitting or if you need an update.

More than 80% of women have been found to be wearing the wrong bra size and the most common fit error found is wearing a band size that is too big. This is probably owing to the old school ‘add 4 inches’ measuring method (from when bras were made of satin and lace and had no stretch in them). So, make sure you are wearing the correct band size- it should be super snug feeling around your ribs, but still allow breathing (!) If you can pull the band out at the back more than a couple of inches, it is too big. 80% of a bra’s support comes from the band, so it needs to be a firm fit.

Woman stretching wearing runderwear original sports bra in blue

Why is running a challenge for your chest?

Running has always be thought of as a high impact activity in terms of breast motion. Research has found that your breasts actually move in a figure of 8 pattern, about 50 percent of the movement is vertical, 25 percent is side to side, and the other 25 percent is anterior-posterior motion. This 3 dimensional motion is hard for a regular bra or crop top to control effectively. This is why you need a specialist sports bra for running in.

KnockerLocker’s front runners

Keep reading to find our top rated sports bras for running.

Our top recommendations are the running specific designed bras from Runderwear; the whole brand is built around providing non-chafing underwear for running and the bras are no exception. Available from C to GG these bras were designed by runners for runners and have really hit the spot. The Runderwear Power running bra is a perfect example of a non-wired encapsulating bra, and for larger breasted ladies it provides super comfortable, firm support. Its high front helps limit the upward phase of the breast bounce and the moulded cups the other dimensions. If it is a non wired sports bra you are after, have a look at our collection.

The Runderwear Energize running bra is for smaller busted runners, again the same focus on comfort and tailored fit and support. Read more of the Runderwear brand story here. If you are usually 34B or sister size the Energize will do you just fine for running, any larger and I would tend to recommend the Power. Runderwear cup sizes come up SMALL- maintain your usual band size but go up a cup size, so for example a 34DD becomes a 34E. This applies to both styles.

woman wearing anita extreme control bra in python print

Many women naturally opt for a racerback feeling that this strap orientation offers more support. Studies have shown this is not actually the case, so maybe consider something with regular straps, particularly if you find a racerback uncomfortable. I find they exert pressure on the upper portion of my shoulder/ trapezius muscle, which is not great on a long run. Anita Active extreme control bra is a fab sports bra for running. It features three-section cups, supported at the sides with a clever side sling to provide maximum support. The combination of tailored, non-wired cups with a seamless inside means it is top notch for comfort.

We also love the Panache sports bras. This range all offer superb support and come in moulded/ not, wired/ not. There really is something for every women. They can be converted into a racerback with the J hook, giving you the flexibility to adapt to whatever your workout, or wardrobe, demands.

If you love an underwire sports bra and are of more ample bosom- the Elomi Energise is one to look at. Developed specifically for larger breasts, the encapsulating, non-compression technology is what makes it such a winner with many. Its four section cup that offers not only bust separation and shaping, but also all the support you need. It can again be converted into a racerback if that is your preference.

If sustainability is high in your product requirements, you need to look at BXM. Ethically made in UK, from 100% recycled fabrics, these bigger bras for more buxom ladies are well worth the investment. Limitless is the high impact option, with sizes ranging from 32E to 38H, this bra is an absolute winner, so supportive, so comfy and made with the planet in mind.

And lastly, please please please, do not wear a crop top if you are more than a petite C cup. They simply do not provide the support your breasts need and ultimately, skin stretches and they will sag. Crop tops are also the culprits behind much breast chafing that goes on.

All of these bras (except the Runderwear Original) are rated as Power 4 or 5 by KnockerLocker- this means our DD+ cups find these good for all high impact activities such as running. For other high impact sports bra, have a look here.

Ladies, get yourselves into the right sports bra for running- give your breasts the best support they can get, leaving you free to focus on enjoying your favourite scenery and playlist whilst you rack up the miles! Remember that 5% of the price you pay for every bra at KnockerLocker goes straight to Pink Ribbon Foundation, supporting those whose lives are affected by breast cancer.