Hey, it's Sarah.  I'm going post on Thursdays.  This is Dawn practicing a plank...30 second hold, way to go!  A good plank involves your total body.  You get shoulder stabilizing, deep abdominal activation, and core muscle endurance.  Practice your plank every day, imagine your body is floating,  and don't forget to breath!  Come to Urbancore and we'll help you get more out of your plank...and then some!