Bras need a design overhaul if women are to be encouraged to do more sport, researchers have concluded after analysing how breasts move under stress.

Scientists found that during exercise a woman’s breasts move in three dimensions, including forward and back, whereas bras are designed only to stop up and down movement.

An estimated 60 per cent of women suffer breast pain during exercise — even during gentle activity — and others are embarrassed by their breasts bouncing when they run.

Pain caused by breast movement affected women of all cup sizes, whether they were an A-cup or a JJ, Joanna Scurr, of the University of Portsmouth, found. Just as significant, she said, was the finding that breasts move as much during a slow jog as when women are sprinting at top speed.

Dr Scurr said that the design of bras, including sports bras, was unable to cope with the three-dimenional movement which stretched the tissue and caused discomfort. “Bras are designed to support up and down movement,” she said. “We found they move up and down, from side to side, and back and forward. Previous research has only looked at vertical movement, which we found contributes only 50 per cent of the overall movement.

“Breasts move in three dimensions. Current bra design is inadequate and I think it is putting women off exercising. There really are women who want to do exercise but who don’t have the bras to cope. It is only recently that bra design has turned to science. There was no research. It’s like designing a car without first thinking, ‘What is the purpose of this?’ We need to think, why do we need bras? What do we need them to do?”

The sports scientist cited the example of a 16-year-old who gave up basketball — despite being selected to play for her county — because she was unable to find a suitable bra.

Dr Scurr carried out a two-year study into the effects of exercise on breasts, in which 70 women were monitored during a variety of activities. Among the volunteers was a woman with a cup size bigger than the F-cup of Katie Price, the glamour model known as Jordan.

The researchers found that breast movement was determined by muscle levels, mass and the body mass index.

A woman’s breasts moved the same amount in and out, up and down and from side to side when she was walking, they concluded. But when a woman started to jog or run, movement changed to resemble a figure of eight pattern, with 51 per cent of the movement being up and down, 22 per cent side to side and 27 per cent in and out.

They concluded that the best form of support available at present was an encapsulation bra, which had separate moulded cups, rather than a compression bra which flattened the breasts to the chest wall.

Encapsulation bras, said the researchers, allowed each breast to move independently and they provided more sideways support.

In A-cup women, sports bras reduced breast movement by 53 per cent, and in G-cup women by 55 per cent.

Dr Scurr, who is working with bra manufacturers to devise more supportive bras, hopes that the development of “intelligent” fabrics will resolve some of the design problems. She said: “If women wore the correct form of support, the use of pain medication will be reduced and women can be active and lead healthy lives.”

The findings will be presented on Friday at the annual conference of the British Association of Sport and Exercise Sciences in Bath.

Times Recommends

• Milk: do we need a dairy godmother?
• DIY: the women doing it for themselves
• First double portrait of Princes unveiled