Tried, tested and loved by you

Tried, tested and loved by you


Finding the right kit with the right fit is crucial for anyone getting active, but can be particularly challenging for women, given the additional requirements for support in the boob department!  

Getting the right sports bra is important, but why? Firstly, a well-fitting bra can make a huge difference to your physical performance by removing any distractions, which is a great way to really accelerate your training for the best results. Secondly a great fitting sports bra can also enhance your body confidence and your mental performance to boot!



Studies at the University of Portsmouth have also found that not having the right support when it comes to finding a supportive sports bra has been proven to be a significant barrier to entry, for women getting active.  


We’ve put together this feature based on some of our frequently asked questions, and popped them all in one place, to help get you up and running quickly.


Why do you need a sports bra?

Boobs are unlike any part of your body - they don’t have any muscles or bone. The only support structure is the Coopers Ligaments, which are very weak, and if left unsupported can become quite damaged, and this is something that cannot be repaired or reversed, so a great fitting sports bra will go a long way to protecting your boobs from unnecessary damage. Your boobs move during a workout considerably more than you might think.  

During a run for example, your boobs (depending on your body shape and size) can move up to 15cms even on a light jog, so reducing movement/bounce is essential to the health of a women's body. Boobs are unique – we're all different, which is why you need a bra that fits your body and is suitable for the level of impact you’re setting out to achieve.



Excessive breast movement can also lead to pain as well as embarrassment during exercise, which can put some women off exercising. As we age, we also experience that natural boob sag, and by working out without the support of a well-fitting sports bra, you could unintentionally speed up the aging process of the breast! 


I don’t have large breasts, do I really need a sports bra?

Even smaller boobs move during a run or workout – your boobs, no matter your size, will move side to side, up and down and back and forth – in fact, technically, your boobs move in a figure of eight as you run, regardless of size.  

No matter your shape and size, every woman should be aiming to support their breasts during exercise, to avoid damaging those irreparable Cooper’s Ligaments, help prevent an accelerated age sag, and avoid any pain, discomfort or embarrassment during exercise.

Every woman needs a sports bra, but depending on your body shape, size and intended level of activity, every woman will need a different level of support to suit.




Can a sports bra improve my workout performance?

Without the right level of breast support during your workout, the University of Portsmouth have found that your upper body muscles could work harder, during your workout, which means you would fatigue more quickly.

The same study also found that when you wear a great fitting and well-supporting sports bra, you benefit from a more efficient running style and improved performance. Although this was only tested in the run category, it’s likely that this would apply across other sports and activities.

Our Power and Energize sports bras have been created with this in mind, and our extensive range of cup sizes really helps to ensure that every woman can have a bra that fits them well, giving their boobs maximum support and comfort with minimal bounce and minimal distraction.


How do you find the right sports bra?

It’s important to remember that just like breasts, no two bra brands are the same when it comes to size and fit, so whether you know your bra size or not, it’s always worth a quick check on your sizing before you order. At runderwear, you can do this over on our Bra Size Finder, as well as an international bra size chart if you just need a quick search. 

When you’re browsing for bras you’ll need to consider the impact level you are intending to use the bra for, the level of support that is likely to work for your body size and shape, and of course, any personal preferences in terms of style and fit.



Why choose a runderwear sports bra?

Here at runderwear we care about making a real difference to your workout, your challenges, your fitness goals and your confidence – in fact, runderwear only exists to solve three problems; chafing, blisters, boob support and distraction-free, confidence-inducing workouts!

As a performance underwear brand, we only deal in the essentials; we are your first layer and second skin, and so with our focus hot in these areas, our bras are designed by runners, for activity, so we won’t let you down!

Focusing purely on underwear means we are dedicated to making bras that fit your cup and band size. When you need serious boob support, it’s usually the case that a small, medium or large simply will not do the job.

We have 3 core bras in our bra range at runderwear. The Power bra is our more structured bra featuring moulded cups with encapsulation, a high elastane content, a wider underband and full breast coverage. According to the University of Portsmouth, these five features are what defines a great high impact bra. Our Power bra provides outstanding support for cup sizes D-H, giving stand-out support for higher impact activities like running, dance and team sports.

Our Energize bra fits cup sizes A-E; Energize offers a compression style and is another great support for higher impact activities. The runderwear Balance bra is a less structured crop-style bra, which some smaller breasted women like to run in, but also offers fantastic support for activities like yoga, strength training and hiking. Balance is a great rest day wear too!


How do I know if my bra fits properly? 

There are some key details you are looking for when ensuring your new sports bra is the correct fit. Your bra should feel snug and supportive on the loosest hook and eye – this means that over time, as the bra wears and loses a little elasticity over time, you’ll be able to tighten your bra to the next hook and eye, ensuring you get the most wear. The underband should be a snug fit and should sit flush against the skin, with just enough room to get two fingers underneath the underband.

Your boobs should fill the cups but not create overspill over the top of the cup. You also shouldn’t see any side boob – the cup should fully support your breast. The fabric should sit smoothly with no dimples or wrinkling.

Your bra straps should sit smoothly and comfortably on the skin, and should neither dig in, nor slip off. You should feel comfortable, confident and well supported in a well-supporting sports bra.

If you have any questions on fitting your runderwear bra, you can speak to our bra fit expert Molly, who will be happy to give you a call and talk through both measuring and fit.

To ensure you do find your perfect fit, we also offer a ‘perfect fit guarantee’ with every bra purchase, which means that not only will we work with you to make sure you find your perfect fit, but we will also provide free exchanges and returns until you find the right size and fit for you. 


Sports bras can feel like quite a big investment – should I go for a cheaper sports bra?  

Getting the right bra is crucial for breast success. (Yep we said that!) When you’re looking at sports bras it’s worth considering buying one great bra, rather than working your way through numerous cheaper options that simply don’t have the support or comfort to give you the best results. 

Cheaper bras don’t usually have all the components required for full breast support, so whilst they might hold your boobs in place, it’s highly likely they won't support you properly, or retain the comfort levels over time.  

This is because the elastane often degrades in washing, and sports bras will lose their initial support. A cheaper bra may also rub and make you sore under your boobs or under your arms – typically known as chafing.

It's most likely that a cheaper bra won't have been tested for activity hour after hour, or tested for their ability to keep the bounce at bay! 

Ultimately, within reason, you usually get what you pay for when it comes to sports bras, so it’s worth investing that bit more in a decent, well-supporting, high-quality sports bra that will see you through some serious challenges. Let’s face it - you cannot put a price on protecting your breasts and enhancing your workout performance.  


Do I need a different sports bra for different activities? 

We recommend finding a fully supportive sports bra that’s made and tested for activity - once you have the correct fit for your body, your sports bra should support you for all your sporting and workout challenges.

To ensure we continue to bring you the best in support, we recently carried out independent bra testing at the University of Portsmouth on our Power and Energize sports bras. During testing the team at the University of Portsmouth found that our Power bra reduces bounce during running by 72%, but what does that mean in more relatable terms? It means that the support of the Power bra reduces breast movement from 9.3cms to 2.5cms during a treadmill run.



During recent research, the University of Portsmouth also found that a great high impact sports bra has 5 key components. These are an adjustable underband, moulded cups, encapsulation, a high neckline and a high polyester content. The runderwear Power sports bra ticks all 5 of these features.

Our Energize sports bra was highly rated as soft, comfortable, lightweight, easy to put on, and easy to adjust. The Energize also provided great support in the treadmill tests and was highly rated by participants.

You can read more about our bra testing here. 

Whilst we didn’t test our Balance bra at this time, we’ve had fantastic reviews from our community of runderwearers who rate it for anything from running to yoga, and spin sessions to rest-day chill. The fit and feel of a sports bra is a very personal choice and we’ve found that some of our customers like to switch it up depending on the activity.


To get supported and distraction free in your next run, workout, hike or ride, head over to our bra fit finder to get started on your runderwear journey, or browse our bras.


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