The leg raise helps strengthen your abdominal muscles and hip flexors, the muscles used to help you move your hips forward when running and walking. You use your abs and hip flexors in practically every activity you do from running and walking to bending and lifting.

Lie on the floor with your hands partway under your buttocks. Raise your legs up so that they become perpendicular to the floor. Lower your legs down until they almost touch the floor. Do 8 to 12 reps.