During exercise, women's breasts bounce more than previously estimated, moving a vertical distance of up to around eight inches.

During walking exercise, women's breasts move relatively the same amount in all directions. But when women jog or run, their breasts move proportionally more in some directions than others: More than 50 percent of the total movement is in the up-down direction, 22 percent side-to-side and 27 percent in-and-out.

The overall pattern of the breast movement resembles a figure-8.

For all cup sizes, the encapsulation bras in which each cup is separately molded provided the most support, beating out the compression bras, which limit only the up-and-down motion. The encapsulation bras limit some of the movement in the other directions, too.

A pair of D-cup breasts weighs about 15 to 23 pounds and women with big breasts experience breast pain during exercise because breasts do not have much natural support.

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