the more flexible you are the less chance you have of being injured, and yoga gives you flexibility and strength, not to mention a really clear head. go to a class or two to get the basics, and then just do the poses and sequences you enjoy and the ones that feel good. dont bother with the stuff thats too hard or doesn't feel right. i really like sun salutations, there are about a million versions of those but the sequence feels really good and its a nice stretch.