Seems so easy to do, until you actually do it! Planks strengthen your abdominal muscles, hips, back and pelvic floor.
How to do it:
Lie face down on a mat. Place both of your forearms on the mat, keeping your shoulders in line with your elbows. Your head should be in line with the rest of your body, while you lift and lengthen it. Avoid straining or rounding out your back. Lift up onto your toes, keeping your feet hip wide apart. Breathe in and then slowly breathe out while contracting your abdomen and glutes. Hold for 15 seconds, resting between each set on your hands and knees. Progress into a push-up position and holding for thirty seconds.