Bored with the usual planks? Take your plank for a sideways walk with this move that'll target the core as well as the upper body. If shapely deltoids are your passion, this move will make them happen.

• Begin in plank position with your hands underneath your shoulders, body in one straight line.
• Simultaneously cross your right hand over your left, as you step your left foot to the left. Then simultaneously step your left hand and right foot to the left, so you're back in plank position. Your hands move together as your feet step apart.
• Repeat this for five steps to the left, and five steps to the right. Be sure to keep the hips low as you move, drawing the navel toward the spine.
• Repeat twice more for a total of three sets.