Much like our everyday bras, research shows that around 85% of women are wearing the wrong size sports bra when they work out.
According to research by the University of Plymouth, unsupported boobs can move over 15cm in each direction when running (ouch) – and your performance suffers too.
Another study from the same researchers found that wearing the wrong bra shortens running stride by four centimeters, which is the equivalent of adding an extra mile to a marathon distance.
Meanwhile, a 2024 paper from Medicine & Science in Sports & Exercise reported that self-selected sports bras can even restrict your breathing.
So, if you want to be comfortable – and you know, breathe – finding their right sports bra is pretty crucial
But with each brand having their own sizing chart and lots of jargon around fit and support, finding the right one can beconfusing.
So, how do you find the right one? We asked some bra pros for their tips on finding the perfect size sports bra for you, and your activity.
1.
It’s worth experimenting with sizing, according to bra fitter, Suzi, from Bravissimo.
‘Sports bras can fit quite snug compared to your everyday bras, so you may find you might need to adjust the size slightly to get the right level of comfort and support,’ she says.
‘You can find your ‘sister size’ by either going up in the cup and down in the band, or up in the band and down in the cup to keep the volume in the cups the same as your everyday size, but with an adjusted fit for the best possible support.’
Even for brands that offer bras in S, M and L sizes, knowing your measurements is important for size guides tools.
Ria, another fitter from Bravissimo, adds: ‘A great way to check if your sports bra fits you well is to make sure you can pull the band from under your arm by one to two inches.
‘This will make sure this is firm enough to really support you, but still fits really comfortably.’
2. Find your impact
The type of exercise you do will have an influence on what typeof sports bra you need.
‘Generally, the level of support needed depends on the activity you are doing, not on your breast size’, says Stephanie Dear, bra expert at M&S. ‘The type of sports bra you wear for Pilates and low-intensity movement should differ from the one you wear for running and high-intensity exercise.’
However, if you have a larger bust, you might want to choose a higher level of support even when doing medium-impact activities, she says, as your bust will naturally move more.
And consider fabrics, cuts and other elements of the bra too, advises Bravissimo fitter Liz.
‘If you’re going a low impact activity like yoga, you might want to go for a non-wired sports bra for extra comfort and flex,’ she suggests.
3. Strap in
‘The straps of a sports bra are key for offering the right support – keep this in mind when choosing a sports bra,’ says Stephanie.
She advises choosing a sports bra with adjustable, wide straps for an optimised fit. Ideally, the under band will be adjustable too – though this is more important for high-impact activities than medium- or low-impact.
‘Adjustable, thick straps provide greater support, help to distribute the weight evenly and prevent the straps from digging into your shoulders. A sports bra with a cross strap is a great idea too, as it offers extra support and hold, minimising breast movement.’
4.
Stephanie recommends you ‘always test out your sports bra before buying. Do this by mimicking the activity you intend to do – like jogging on the spot in the changing room – to test out how it feels. You should feel firmly supported and comfortable with a free range of movement.’
If you are still unsure, consider a professional bra fit to ensure you’re wearing the correct size sports bra. You can do this in stores or virtually at M&S, Bravissimo and other bra stores.
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