Work Your Abs in Just 15 Minutes
Lie on your stomach with arms bent, palms and forearms on the ground, fingers pointed forward, legs extended, and toes tucked under (top illustration). Work your back and abs by contracting your core muscles and slowly lifting your entire torso off the floor, keeping palms, forearms, and toes on the ground (bottom illustration). Avoid arching your lower back, hiking your hips upward, or shrugging your shoulders (in other words, cheating). Hold for 10 to 30 seconds, gradually building up to one minute.