weights are pretty light I'm all for constant tension and stuff but in order to look strong you have to be strong. I am by no means advocating super heavy training but imo you have to use fairly heavy loads or build up to them in a few compound movements incline,barbell rows,dips,squat,deads,chins,dumbell presses what ever ones you favor or most just don't get far. Groink made the comment in the arnold thread he can only bench 380 or something well that being able to rep 300 for 10 still very strong. It doesnt have to be bench but a few basic movements have you generally have to be strong in to be at peak.
Most that train light would be capable of using heavy poundage on there favorite movements if they wanted