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The Anatomy of a Sports Bra

Sports bra’s have revolutionised breast comfort and support for active women.  From the humble beginnings of the first sports bra, created in 1977 from two jockstraps sewn together. To the high tech fabrics and designs of today’s modern sports bras.  But what do the different components of the sports bra actually do?  This post examines the anatomy of the sports bra.

Anatomy of a Sports Bra


The cups of the bra are designed to hold and shape the breast tissue.  Sports bras that have cups tend to provide a more natural and separated breast shape.  Cups can also incorporate other features. Including moulding or padding for modesty and shape enhancement.  Some sports bra’s have more of a ‘crop’ look with internal cups. Which are not always obvious from the outside of the bra.

Cup sizes are defined using a letter.  This letter translates to a measurement from your chest wall to the tip of your breasts.  Changing your band size can also affect the size of the cups.


The band is at the base of the bra and goes around your ribcage.  The band of a sports bra is designed to fit more snugly than the band of your everyday bra. Consequently this is where a lot of the support comes from.  Sports bras need to remain comfortable when you are hot and sweaty. Similarly when you are moving around. Hence the band is an important factor.  A well fitting, soft, seam free band is ideal to prevent any painful chafing.


The underwire provides shape and definition to the breasts.  They can help to maintain the cup shape and distribute the weight of each breast.  Many bras designed for larger bust sizes use underwire in the bra design as they help to maintain the cup shape and distribute the weight of each breast.   There are many stories of wires digging in during a gym class or the dreaded wire poking through the end and stabbing you in the breast during a run.  It doesn’t have to be this way!  Finding a good fit so the underwire is not sitting against your breast tissue is a good start.  Many sports bras use ‘flexi wires’ which adjust to your movement and shape.  The wires are normally sewn into a double wall channel with reinforced ends to increase comfort and prevent any ends poking out.

Centre Panel (Bridge)

The bridge is the centre section of the bra that separates and connects the cups.  It is usually a rigid fabric that stabilises the position of the bra on the body.  It works with the straps and wings as part of the core bra structure providing horizontal and vertical support.  The bridge should lay flat and keep the band and underwire flush against your chest.


The bra straps maintain the bra’s vertical placement on your body.  It is a misconception that the straps are the main source of support, they should not take the full weight of your breasts.  Bra straps can be fully or part elasticated to flex with your body as you exercise.  They are often padded for extra comfort, especially in bras with bigger cups sizes and maternity bras.

Sports bra straps come in a huge variety of styles such a regular straps, convertible and racerback.  A key consideration of straps is their position on the body to prevent them slipping down during activity.  The overall fit of the bra can also affect bra slippage; if your band is too loose and rides up your back as you jump around, this can cause the straps to fall off your shoulders.  This may then cause you to compensate by tightening the straps too much which can cause them to dig into your shoulders, becoming very uncomfortable.

Strap Attachments

Some bra straps are permanently sewn into the cups and back of the bra while others have strap attachments that can be undone and allows you to customise the style.  These are mainly found on ‘convertible’ straps which can be worn in a regular style or crossed over.

Strap Adjusters

Most sports bras have the ability to adjust the length of the straps.  This is an important feature as the length of a woman’s torso is variable and a ‘one size fits all’ approach will not work.  The elastic in the bra straps can also stretch over time due to wear and washing, so it is good to be able to tighten them.  The type of adjusters can vary from a simple sliding ring like most everyday bras, to velcro front adjusters.

Bra Sides/Back (Wings)

This part of the bra supports you around the sides and back of the bra.  It is often wider on sports bras than your everyday bra, especially at the sides, to help you feel more supported and ‘tucked in’ while your torso is moving in different directions.

Hook & Eye

Not all sports bra’s use a hook and eye clasp, but they are the most common fastening.  They vary in the number and width but are often three sets of two or three hooks.  This can increase to four on some bigger band and cups sizes and maternity bras to allow for a greater range of size and customisation.  It is ideal to have a new sports bra on the loosest setting, so as the bra stretches a little over time (with wash and wear) you have the ability to tighten the band and increase the longevity of the bra.  If you are in between bra sizes you can use a band extender which attaches to the hook and eye and increases the band size by about 40mm.

As can be seen the ‘Anatomy of a Sports Bra’ is quite complex with many individual components working together to provide you with the best fit and support. This is essential to ensure your breasts are adequately supported and your upper body does not incorrectly take the load of your breast movement as this is the job of your sports bra. Use the above info as a check list to make sure the sports bra you wear is the best for you.

Now you have been armed with this information check out our range of sports bras and find the perfect one for you.

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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