This is killer on the abs, and it's the only exercise I know that trains upper-body pushing in a smooth manner that begins like a horizontal press (the bottom of each rep) and finishes like a vertical press (the top of each rep). Since you can't do much for adding load to this move outside of wearing a weight-vest, I prefer to do this exercise as a burnout for max reps toward the end of a workout. – Nick Tumminello
