Young Sport Girl Wearing A Sports Bra

About 50 percent of women report some pain or discomfort in their breasts during exercise. This varies considerably in intensity and may depend on what they are wearing. In an Australian study 3 women (17-21, cup sizes B and C) were photographed exercising bare breasted, again wearing two different bra models, and a fourth time wearing a specific sports bra. As expected, breast motion was reduced by bras, and the sports bra was the most effective. The women reported less discomfort with bras and especially with the sports bra. However not all sports bras are created equally and a woman should be properly fitted.
During 2007, scientist Dr. Joanna Scurr of the University of Portsmouth conducted a motion study of seventy women while running. They represented the widest range of breast sizes ever studied, including women with cup sizes DD, E, F, FF, G, H, HH, J and JJ. Glamour model Jordan, whose bra cup size is F, is six cup sizes smaller than Dr Scurr’s biggest breasted subject. Scurr found that breasts move in three planes of motion during exercise. vertically, horizontally, and laterally, in an overall figure-8 motion. Unrestrained movement of large breasts may contribute to sagging over time. Motion studies have revealed that when a woman runs, more than 50% of the breast's total movement vertical, 22% side-to-side, and 27% in-and-out. The 2007 study found that encapsulation-type sports bras, in which each cup is separately molded, are more effective than compression-type bras, which press the breasts close to the body, at reducing total breast motion during exercise. Encapsulation bras reduce motion in two of the three planes, while compression bras reduce motion in only one plane. Previously, it was commonly believed that a woman with small to medium-size breasts benefited most from a compression-type sports bra, and women with larger breasts need an encapsulation-type sports bra. Scurr's study disproved that belief.
Some female athletes are concerned that a sports bra may interfere with breathing, but even though increased pressure on the rib cage has been demonstrated, no significant effect on breathing can be shown.