This is one of those try before you buy things - choosing a sports bra is no small matter. It's all very well to bounce to the beat (ouch!) - but there are actually some serious features to look for before you get your sports bra. After all, you want your exercise experience to be a pain free and comfy one.
So what can you look for?
to control the bounce - less vertical stretch than horizontal stretch
for more support - the straps must be wide and made of firm, grippy non stretch fabric
to avoid allergies - the material must be of non allergic and non abrasive fabric
to prevent chafing - hooks must be covered; labels must be covered or hidden
to stop the bra riding up - a wide elastic band to snugly fit your ribs
for free arm movement - T back style if you play tennis, squash, etc.