30 Day Plank Challenge -  Benefits of Plank Exercise: *It strengthens your lower back.  *It develops your core muscles – which include the abs, back, hips and the butt.  *Helps you to avoid injuries and encourage good posture. *Can be done anywhere.  *Develops your abdominals by targeting the rectus abdominis.  *This is the BEST for toning and strengthening the core.