My hubby is fond of saying, "If you do what you've always done, you will get what you've always got." I think this applies to exercise. I've been working out like a mad woman, but I fell into a routine of doing the same sprints, the same exercies, etc. each week.
I've been taking a cycle class that mixes things up. We've had a different instructor and he is a MACHINE! I've finally lost a few pounds. I guess the saying is right - if you keep exercising the way you always have you will get the same results.