A back injury can be a major set back but I am glad you are doing all you can to stay in shape. Congrats on the marathon keep us updated!!

One of favorite exercises to do when training core and abs is a plank. This video shows a rep set using your abs to get you into a plank position on a stability ball thats great to throw in between your regular core workouts. Your holds can last as long as you want to maximize your workout but for b...