As most women would attest, it is almost impossible to take the jiggling out of jogging.
Even the most expensive sports bras can fail to stop the painful bouncing which leads to long-term damage.
But now scientists claim to have found a way to make the perfect scaffolding for every woman's set.
They have developed an "intelligent fabric" to use when testing bra designs in the lab.
Fitted with tiny sensors, the fabric will monitor and measure even the smallest movement in the breast.
This means that manufacturers can better stop the wobble - and also prevent their designs from adding to the problem.
The fabric has already been used to pinpoint faults with current bra design.
The creators, at the University of Wollongong in Australia, gave two women the sensor bras.
The volunteers, aged 30 and 39, one wearing a 36D bra and the other a 38DD, were instructed to walk on a treadmill at 4.3mph and then speed up to a jog of 6.2mph.
Even the most expensive sportswear can fail to take the jiggling out of jogging
From the sensors, the team was able to glean that all the strain and stress from the breast movement was being borne by the straps.
This was causing the shoulder pain and tingling in the arms that many women suffer - and could cause long-term nerve damage.
Reporting their findings in the latest issue of the Journal of Biomechanics, they say: "A consequence of current brassiere design is that the brassiere straps bear much of the load generated by breast momentum during physical activity.
"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."
The experts add: "Apart from strap-related pain, many females, particularly largebreasted women, are restricted from participating in physical activity due to exerciseinduced breast pain associated with excessive vertical breast displacement."
According to the sensors, the greatest vertical movement was monitored in the larger woman at a maximum of 2.7in during jogging.
That compared to a maximum of two inches in the smaller woman. Movement during walking ranged from 0.4in to one inch.
The scientists believe the findings can be used to design bras that limit excessive breast movement without causing discomfort.
They said: "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."
Until now, they said, most of the technology used was comprised of rigid parts, such as strain gauges or buckle transducers, which could interfere with performance and did not give an accurate picture.
They said recent advances in polymer science had allowed 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.
"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."
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