Planks are awesome, but if anyone wants to take core work to the next level, try pilates. I shied away from it for a long time because the high cost, but there are excellent and inexpensive monthly subscriptions to Web sites offering great at-home pilates routines. Although pilates focuses on working core muscles, good workouts will include the full body. In the four months I\'ve been doing pilates regularly my DW increased (for the first time in YEARS) and I\'ve gained more upper back and arm strength. I\'ve also noticed far fewer back problems and less fatigue when I carry a weighted pack, which is probably from engaging core muscles instead of using (or mis-using) back muscles. For what it\'s worth...