Photo: Jenn Zerling/JZ Fitness
1. Grab a rolled towel or a medicine ball and place it between your knees. Make sure your feet are flat on the ground with your knees facing forward. Place your hands on either side of your hips.
2. While engaging the core muscles, lift both knees up about two inches toward your chest.
3. Extend both legs outward and squeeze the thighs inward. Hold the squeeze for 3 counts and then release.
4. Reps: 15 (keeping the towel or ball between your knees at all times).