Planking is a great body weight exercise to help strengthen your core muscles, which are necessary for supporting your back and abdomen. Depending on which plank variation you choose to do, it also help to make your hips, pelvic floor, shoulders, arms or other upper-body muscles stronger, too. A strong core is needed to provide you with better stability, posture, and to help you perform everyday activities with ease. You don't need any fancy equipment to plank—just a couple minutes and a spot on the floor. How many calories you burn in a plank depends on your speed, weight and gender. To see how many calories you burn in a plank, use the calculator below.