The first exercises you would do in a pilates workout is The Hundred. It strengthens your abs and increases your circulation and prepares you for the other mat exercises. It is an excellent exercise for reducing that belly. Done correctly, you should feel the strain in your abdominal muscles, not your back. If your back hurts, then you're not doing it right.
A few points to take note of.
The first time you try this exercise, if your abdominal muscles aren't strong enough, you might not be able to do the classic way. To make it easier, you can rest your feet against the wall until you get the hang of it.
These pilates sample exercises show you how pilates The Hundred and a few other classic pliates exercises are done. You'll find more free workout demos at http://www.home-weight-loss-programs.com/exercisevideos.html
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