Exercise usually results in a large displacement of the breasts, often leading to breast pain. Although breast pain is a common concern of exercising females, little research has been conducted in the area of breast pain. It has been suggested that a cause of breast pain is excessive breast motion. As the female breast does not contain strong intrinsic structural support, this breast motion is difficult to reduce. It is suggested that the primary anatomical support for the breast is the Cooper's ligaments; however, their true functional properties are unknown. Because of the lack of internal breast support it has been suggested that the skin covering the breast may also act as a support structure for the breast, but this has not been quantified. In an attempt to reduce breast motion, external breast supports (brassieres) have been developed. This article discusses components of current sports brassieres with implications for future research required to improve brassiere design and performance.