Advanced Plank
As with the beginning (bent knee) and intermediate (straight knee) plank exercises, this one is all about maintaining good positioning. You'll start in a straight plank position, holding the position for perhaps 30-60 seconds, then as you roll toward your stomach and onto your other side it is important to maintain the abdominal "brace" and good body alignment. When you get to the other side, don't drop those hips! Keep your body straight as a plank, and hold on the other side. Do not advance to this exercise until you can do the straight plank in good form for at least 60 seconds.