Basic Planks: In a pushup position, keeping your body straight from head to toe, use your abdominal, thigh, back, and arm muscles to keep your torso up while your toes and forearms support your weight. But holding a fixed position will not maximize the muscles being worked. Personal trainer Matt Roberts recommends introducing some movement by switching from the lower board to the raised board and vice versa.
From a “low” plank position with forearms on the ground, progress to a “high” plank by first placing your left hand under your left shoulder and extending your arm, then placing your right hand under your right shoulder, lifting until both arms are extended. “You should always maintain a straight line through your body, with your hips
