Assume a plank position on the ground. You should be supporting your bodyweight on your toes and forearms, keeping your torso straight. Your forearms should be shoulder-width apart. This will be your starting position. Pressing your palms firmly into the ground, extend through the elbows to raise your body from the ground. Keep your torso rigid as you perform the movement. Slowly lower your forearms back to the ground by allowing the elbows to flex. Repeat.