Many women wear the wrong size of bra, often a cup-size or two out. It is important to get the right support for your boobs and back by wearing the right size, especially when it comes to sports bras, as adequate support is essential when exercising. The classic mistake most women make is choosing a bra that is too loose around the back. To check this, stand sideways on to a mirror. Your bra should lie in a straight line across your back rather than riding up. Also ensure your sports bra suits your activity. For example, a high impact routine such as aerobics and running will require more support than cycling, walking or weight lifting. If you are not sure of your correct cup size you can get bra-fitting services in some stores selling bras such as Woolworths.