Boobs, bust, knockers, bazookas, melons, bosom, mammary glands…whatever you like to call them, breasts need our support when exercising. Loved by some but hated by many, sports bras should be friends with our breasts. Unfortunately, some women find sports bras a hindrance, but with increasing research into how our breasts move when we exercise and the causes of breast pain, the science behind finding a perfect fitting sports bra is now more supportive than ever.
It is known that around 70% of women will experience some form of breast pain (mastalgia) in their lifetime(1). If you are noticing pain that is unusual or cannot be explained, please seek help from your GP. However, the most common cause of mastalgia is due to normal hormonal changes during the menstrual cycle. Mastalgia may be accompanied by fullness or heaviness of the breasts and can vary between women. Commonly, mastalgia will increase progressively from around ovulation, and ease off during menstruation. Breast pain may also be exercise-induced or caused by an ill-fitting bra(1). Understandably, many women report that mastalgia is a reason that they refrain from exercise. However, the good news is that with a great fitting (and on-trend) sports bra, mastalgia has been shown to significantly reduce(1,2).
Before we talk about finding a good fit, let's discuss how our breasts move – the biomechanics of breasts.
When jumping, breasts have been shown to move up to 17cm vertically (this is the ‘bounce’)(2,3)
When running, breasts may move up to 10cm vertically(2,3)
Breasts can also move sideways, and forward-backwards between 1-4cm, depending on how your torso is rotating(1,3).
Bra slap: when breasts hit the chest wall and make a ‘slap’ sound
Higher running cadence is associated with a greater amount of bounce(1)
Friction from a bra is more commonly reported in endurance athletes(1)
Research is still unclear whether there is a link between how much our breasts move and whether this is a source of pain. However, when suffering from mastalgia, sports bras have been shown to greatly decrease pain associated with movement(1,2,3). It’s also understood that women with a larger bust are at an increased risk of suffering from more severe mastalgia. So how do you know which sports bra to choose?
Thanks to a recent 2020 study(1), there is now a checklist of tips for choosing a great sports bra (figure 1 below). One of the biggest mistakes we make is choosing a bra that’s over supportive (clingy much?) – this is associated with greater discomfort and an increase of friction type pain/injury. It appears that the perfect balance between comfort and support is around 60% reduction in bounce. Other tips to follow include:
Try lifting your arms above your head in the changeroom – the band under bust should NOT ride up
Underwire must follow your natural breast shape. Make sure it follows your entire cup size, including underneath your armpit
Choose a bra based on the loosest hook. This leaves room for it to stretch
Ensure no crinkles in the cup, and breasts do not bulge over the cup
What about style? Which sports bras should you even bother trying on?
There are 4 basic styles of sports bras(2):
Encapsulation: each cup is separated individually by wire, with a wide under bust support band. Cup shape is generally mesh. Bounce reduction percentage is generally between 55-65%. These are my personal favourite!
Crop: The most stylish of them all, but least supportive. Crop bra’s are wire-free with a wide elastic band under bust
Hybrid: A combination of encapsulation + crop. Hybrid sports bras are relatively new on the market and usually provide a bounce reduction of >70%. They are often wire-free and divide your breasts by a soft moulded cup and use a wide elastic under the bust.
Compression: generally recommended post-surgery. Compression sports bras work by pushing your breasts against your chest wall, and dividing your breasts by a soft mould. They are essentially a crop type bra with much greater support
What about those pesky bra straps? Bra straps are really just personal preference. Wider straps are generally more comfortable and better for distributing weight over your shoulders (better for bigger busts). Razorback styles are good for those who frequently complain of bra straps sliding off their shoulders. Razorbacks may not be advised for bigger busts as they place a lot of breast weight through the upper shoulder region(4).
There you go ladies, I hope that provides you with some more clarity the next time you head for the bra fitting change rooms. If you’re losing the motivation to exercise because of mastalgia, please remember you’re not alone. It’s probably a great time to treat yourself to a fresh new sports bra!
For those wanting further guidance on selecting the perfect sports bra for them, we can highly recommend the crew at She Science. They offer in-house customized fitting at their Camberwell facility, but also have instructions for online fittings, plus some great tips on their blog! Check them out here
If you have any questions or concerns, please don’t hesitate to reach out to us
References
McGhee, Deirdre E.; Steele, Julie R. Biomechanics of Breast Support for Active Women, Exercise and Sport Sciences Reviews: July 2020 - Volume 48 - Issue 3 - p 99-109 doi: 10.1249/JES.0000000000000221
Brown N, White J, Brasher A, Scurr J. An investigation into breast support and sports bra use in female runners of the 2012 London Marathon. Journal of Sports Sciences. 2014;32(9):801-809.
Jie Zhou, Winnie Yu, Ng S. Methods of studying breast motion in sports bras: a review. Textile Research Journal. 2011;81(12):1234-1248.
Coltman C, McGhee D, Steele J. Bra strap orientations and designs to minimise bra strap discomfort and pressure during sport and exercise in women with large breasts. Sports Medicine - Open. 2015;1(1)