I am looking at exrx.net and trying to figure out what the difference b/w the two movements is. Is it the positioning of the elbows? Pointed out for chest dips, pointed in for tricep dips? In chest dips, do you lean forward as opposed to leaning backwards for tricep dips? I have never really done these movements because I am pretty week and can't really do many. I am thinking of doing this machine for chest dips to build up strength: http://www.exrx.net/WeightExercises/PectoralSternal/LVChestDip.html Is that advisable? I have read such positive things about this chest exercise. I really don't want to exclude it from my routine.