Many women feel pain in their breasts while running due to an excessively large degree of breast movement. Therefore, most sports bras pursue a reduction in breast movement. The purpose of this study is to investigate the breast movement reduction effect of a selection of sports bra designs according to the intensity of the sport and the breast size of the wearer. The study measured differences in the vertical movement of the nipple with 4 types of sports bras and 3 exercise speeds(4km/h, 7km/h, and 10km/h). Subjects included women in their 20s with bra sizes of either B cup(n=3) or C cup(n=3). The results of the study are as follows. Breast movement differed according to running speed and breast size; breast movement significantly increased starting with jogging speed(7km/h), and the C-cup group had a larger degree of vertical movement than the B-cup group. A superior effect on breast movement during jogging(7km/h) and sprinting(10km/h) was observed differently by bra cup sizes. To C-cup group, encapsulation-style sports bra, which provides horizontal support across the upper breast and padding inside the shoulder strap and bra cup to ease impact was most effective and next effective style was the compression-style bra with a princess line to cover the breasts solidly. Most style sports bra were effective in the B-cup group. Besides aforementioned encapsulation-style sports bra, the compression-style bra with a band, which presses the breasts against the chest wall, reduced breast movement effectively.