Standing Knee Crunch
1. Stand tall with your left leg in front of the right, and extend your hands up towards the ceiling, your arms straight.
2. Shift your weight into your left foot, and raise your right knee to the height of your hips. Simultaneously go up on the toes of your left leg, while pulling your elbows down by your sides, your hands making a fist. This creates the crunch.
3. Pause at the top of the movement, and then return to the starting position. Repeat the sequence with your right leg as the standing leg. Repeat.