New research could take the pain out of searching for a sports bra
If you’re a female athlete, you’ll probably know the struggle. Finding the right sports bra can be every bit as taxing as a tough triathlon training session. In collaboration with the Swiss materials research institute Empa, a start-up named Swijin has now developed sports bras with special properties.
Swijin founder Claudia Glass was out jogging in Mallorca when the idea came to her. That day, the sea looked so temptingly blue that she felt like rounding off her run with a swim. But there was a problem: her bra. The thought of walking back to the hotel with wet fabric clinging to her chest put her off the idea of taking a dip.
The trouble with sports bras
After doing a little research, she soon realised she’d found a gap in the market. Just as bikini tops are unsuitable for running, sports bras are unsuitable for swimming. With this in mind, she decided to develop her own sports bra. «To be honest, I completely underestimated what it’d take to get something like this off the ground,» she recalls.
Sports bras, after all, have their pitfalls. Some don’t offer enough support, causing 44 per cent of women to experience pain while exercising. Meanwhile, other bras pinch, chafe or constrict. In the process of raising funds for her idea, Claudia did market research that revealed an inverse relationship between comfort and support. If a bra offers good support, comfort suffers. Comfy bras, on the other hand, offer poor support.
Elite sportswomen aren’t the only ones affected by the issue. In fact, another study cited that 17 per cent of women who do recreational sport are put off exercise as a result of ill-fitting sports bras and breast pain. That makes breast issues the fourth-biggest motivation killer when it comes to physical activity.
Research: breast size and support impact athletic performance
It quickly dawned on Claudia that she didn’t just want to develop a swimming/running bra. It had to be a well-fitting, comfortable, quick-drying bra for all sportswomen. A sports bra that fits well isn’t just a matter of comfort – it also affects athletic performance.
Source: Siri Schubert
As part of a small-scale study conducted by the University of Memphis, researchers found that greater breast support is associated with lower oxygen consumption and better running economy. In other words, bras with good support can improve performance.
An earlier study carried out on 168 participants after the 2012 London Marathon showed that breast size impacted women’s finishing times – regardless of their body mass index. There was a 34.4-minute time difference between runners who wore an 80A bra size (36A UK) and runners who wore an 80DD (36DD UK).
Even if you prefer a leisurely jog, your bra still factors into your performance. Another study demonstrated that pain caused by breast movement in all directions can also flare up during slow runs.
Collaboration with Empa
Switzerland’s innovation agency (Innosuisse) saw potential in a bra that could address these problems and supported Claudia’s project with more than 300,000 francs in funding. Swinjin’s collaboration with Empa’s Biomimetic Membranes and Textiles Department also came about as part of this funding. «We would never have got this far without Empa,» Claudia says when we meet at Empa’s St. Gallen premises.
We’re joined by Simon Annaheim, Empa’s Scientific Group Leader. He’s especially interested in the biomechanical side of things; the up and down movement of the breasts affects body movement as a whole. Scientists are now looking into a connection between breast movement and knee injuries.
Source: Siri Schubert
The project that Simon’s running saw the development of a special manikin with near-natural breasts. It’s kitted out with sensors and motors to examine the forces that act on the breasts during exercise. At the same time, the setup measures how much different bras restrict breast movement.
Empa researchers are also looking into how quickly the material of the new bra dries. The goal? To make sure athletes don’t cool down when they sweat or after switching from swimming to cycling during a triathlon. Since wet clothing also rubs more, it’s important for a bra to dry quickly to prevent painful chafing.
Empa has now published its initial research findings on the Swijin project. According to the report, the sports bra achieved very good results in terms of support, temperature regulation and fit. The goal of the research is to create a scientifically sound approach to developing better sports bras with specific properties for different types of sport.
The fabric comes from castor beans
Finding a suitable yarn that was light, durable and quick-drying presented Claudia with yet another obstacle. «Our first synthetic prototype felt like a scouring pad,» she says. «Definitely not a material you’d want anywhere near your breasts.» She then got a crucial phone call from Empa. The researchers had come across a material that both ticked all the boxes on functionality and came from a renewable raw material: castor beans.
The fibres made from the material are water-repellent, so they dry very quickly. They’re also just as stretchy and tear-resistant as petroleum-based high-performance fibres.
There seems to be potential here
The demand for well-fitting sports bras is increasing. According to market research agency Grey Views, the sports bra market is set to grow to a value of 103.5 billion US dollars (92.9 billion francs, 98.6 billion euros) by 2029. It’s calculated that sports bras worth a total of roughly 9.7 billion euros (9.1 billion francs) will be sold in Germany alone in 2029.
Swijin now offers two different sports bras: the Freeli and the Schnuggi, both with high support. A third bra for larger bust sizes is set to launch soon. They don’t need clasps or adjustable straps, so the risk of chafing is reduced. Galaxus doesn’t currently stock Swijin bras.
Professional athlete Anna Zehnder wears the bra for competitions
Professional sportswomen have started wearing the new Swijin sports bra. One of them is the Swiss pro triathlete Anna Zehnder, whose greatest successes include being named runner-up in the 2023 World Cross Duathlon Championships and runner-up in the 2024 European Cross Triathlon Championships.
Source: Xterra/Carel du Plessis
Although Anna has a relatively small cup size, her back has grown muscular through swimming. For a long time, this made it challenging to find a sports bra that fit. She was also bothered by chafing seams and friction from the thick underbust straps that many sports bras have. In triathlons, sports bras that soaked up water were especially problematic. They slowed her down when swimming, and the wet, cold fabric was uncomfortable during the cycling and running sections.
Source: Xterra/Carel du Plessis
Anna doesn’t have these difficulties with the Swijin bra: «I hardly feel it, and it gives me good support and hold,» she tells me in a telephone interview. She goes on to explain that it doesn’t get waterlogged and that it dries extremely quickly. It’s the bra she chooses to wear to training sessions and competitions. But she sees yet another plus point in the Swijin bra: «I like the classically elegant look.»
Header image: Siri Schubert
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Siri Schubert
Senior Editor
Siri.Schubert@digitecgalaxus.chResearch diver, outdoor guide and SUP instructor – I love being in, on and around water. Lakes, rivers and the ocean are my playgrounds. For a change of perspective, I look at the world from above while trail running or flying drones.
