The speed at which women's breasts wobble when they run could be key to understanding breast pain and could also have significant implications for new bra designs, according to a leading expert.
Sports scientist Dr Joanna Scurr at the University of Portsmouth said that chest tissue is more likely to be damaged by the speed the breast moves rather than the amount of movement.
"It's not the degree of movement which is important but how fast it moves," The Sun quoted Dr Scurr, as saying.
Dr Scurr studied more than 100 women running on a treadmill with sensors attached to their bosoms.
The distance travelled by the breasts was measured, following which the speed at which they moved up and down, in and out and from side to side was calculated.
"We discovered that the speed at which the breasts move changes during the running cycle," she said.
"And we found that the subjects' experienced the greatest degree of pain and discomfort during the points at which the breast was in the process of accelerating or decelerating.
"Little is understood about the causes of breast pain but studying how and why the breast moves is fundamental and speed could be a huge factor.
"This research could have implications for millions of women who suffer from exercise-related breast pain and could have significant implications for bra design," she added.
The study is being carried out at Britain's first Research Group for Breast Health based at the University of Portsmouth.
Dr Scurr said: "Breast health is an under-researched area and we hope to broaden our understanding."