It's also important to remember that when you lift your knees your abdominal muscles engage. This means that the higher you lift them the more you work your muscles. The exercises that incorporate knee lifting help to slim the waist by burning belly fat and creating abdominal muscle.
In order to really get on a plan that will shrink your tummy and help you look slim and trim you have to be ready to dedicate yourself to it. Write on a calendar. In fact, write it in pen. Tell your family that you're unavailable between the time that your workout starts and when it ends. Walk more. Losing weight naturally through good nutrition and commonsense is really the only way to lose those extra pounds and to keep it off permanently.