Lunge to Overhead Press
This may not look like an ab move, but Montenegro says it will really feel like one—the abdominals will be working overtime to stabilize the body, especially as you press the weights overhead.
1. Hold the dumbbells at shoulder height.
2. Start in a lunge position, with your right knee bent 90 degrees in front of you (be careful not to let the knee bend over your toes) and the left knee slightly bent behind you. Imagine a string pulling up from the top of your head, keeping the neck and back long.
3. As you straighten both legs to come to standing, engage the abs and press the dumbbells up over your head.
4. Bend the knees to come back to the lunge and lower the weights to shoulder level.
5. Do 6 reps, then switch legs. (To make this move harder, Montenegro suggests walking forward while doing the lunges.)