Hm. Well first of all you have to get the concept of "tone" out of your vocabulary. Crunches and leg lifts aren't going to get you the look you want.
Don't get me wrong - crunches and leg lifts and other core-type exercises are GREAT for you. You need those strong core muscles. But they're not going to firm up the "flab".
First thing is that the only thing that will remove the flab is losing weight. That's the unfortunate truth. You can't spot lose or "spot tone" ... you can only lose and realize that most of the time belly fat is going to be the last bit of fat to go (especially for women).
Next thing is that if you want to build muscle definition, resistance work and weights is the best way to go. It'll help firm you up all over, which will help you lose those last pounds, which will ... ultimately reveal those muscles and give you that healthy, fit look you want.
One DVD that comes highly recommended is the Calanetics series - which is mostly about body resistance work. I've done it before and while I personally can't get into it, I will say it's a good solid workout and I know a lot of people who swear by it.
But even w/out using a DVD or tape, some things you can do to help build muscle are lunges, squats, stepups, pushups, and tricep dips. Just doing a combination of those (along with crunches of course) will really give you a great all over body workout!
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