They might not look like much, but a lot goes into the design and manufacturing of a sports bra. It starts off with research, development and testing, and that’s all before they start getting manufactured. Some bras take years to develop, especially since they are designed with performance in mind across a huge range of sizes (compared to clothing and shoes).

Not only do they have to feel good, they also need to stretch, bend and work with your body. From technical moisture-wicking fabrics that stay dry and feel soft, to elastics, padding and zippers that can stand up to time, every detail is considered to make sure your bra is comfortable, durable, fits perfectly and supports your breasts in motion.

They might look daunting at first, but once you get the hang of size guides they should help you find your starting point. But it’s important to remember — the best way to get the best bra fit is to try it on.

For Nike bras, our sizes start small and increase in band size, cup size and strap height as you get into larger sizes. Depending on the style of bra, this could be done in a few different ways. Some of our scales include cup sizes, so you can use these to help you figure out which one is right for you. Other styles (often those without separate cup moulding) use a staggered approach ranging from XS to XL.

It’s important to remember that your breasts change size all the time. They’ll shrink and grow based on your weight, during pregnancy, and during your periods, so it’s a good idea to bear that in mind when looking for your perfect fit. A bra that fits on the first day of your cycle, might feel completely different a few weeks later, so it’s worth having a few different styles and sizes so you’re always covered.

Check out our other NAQs to learn more about the common questions you've had about bras, breasts and exercise.