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Scientists have developed an "intelligent fabric" with its own sensors that can be used to design bras for women more accurately in the hope of putting an end to the discomfort and even long-term injury that can result from poor bra design.
Researchers have established that even when the bra is the correct size and properly fitted, women can suffer pain and even nerve damage from bra straps.
The vertical movement of the chest can exceed 70mm (almost three inches) during vigorous effort and they say the stresses and strains can affect nerves around the shoulders so seriously that it causes numbness in fingers.
Better support is needed because the female breast contains no supportive muscle or bone.
"A consequence of current brassiere design is that the brassiere straps bear much of the load generated by breast momentum during physical activity," say the researchers in the Journal of Biomechanics this week.
"As breast mass increases, breast bounce momentum also increases, placing large loads on the straps and, in turn, excessive pressure on the wearer's shoulders."
They add: "Apart from strap-related pain, many females, particularly large-breasted women, are restricted from participating in physical activity due to exercise-induced breast pain associated with excessive vertical breast displacement."
In the research at the University of Wollongong, in Australia, scientists designed a special fabric with sensors to detect movement as women walked and jogged on a treadmill.
Two women aged 30 and 39 with a 36D and a 38DD brassiere took part in the research where they walked at 7 kilometres an hour (4.3 miles an hour) and jogged at 10 kilometres an hour.
The greatest vertical movement was monitored in the larger woman at a maximum of 68mm during jogging.
That compared to a maximum of 53mm in the smaller woman.
Movement during walking ranged from 11 to 25mm.
The researchers say future bra designs must limit excessive breast movement without causing discomfort.
"It is imperative that brassiere designers have access to methods that can accurately and reliably quantify the effects of various brassiere design features on breast motion while not altering the material properties of the brassiere," they say.
"However, most commercially available technologies have traditionally been comprised of rigid parts, such as strain gauges or buckle transducers, which can interfere with performance."
They say recent advances in polymer science allow sensors to be built into fabrics to monitor human motion.
"Our results show that the fabric sensors are suitable to monitor breast motion and brassiere function," they say.
"Brassiere designers will have the ability directly to assess the effects of changes to each brassiere component on vertical breast and brassiere motion using fabric sensors."
- INDEPENDENT
