I went to the gym last night and was working on legs. I worked into a set with a guy on the Hack-Sled. That is an inverted leg press. I normally work out with about 230lbs not counting the weight of the machine. Well, we started out with 270lbs, i did my normal set reps with that, then we went to 360lbs, normal set reps with that as well. He then placed 6 pairs of 45lb weights; 1 set =90lbs, totaling 540lbs. I did 10 reps at that weight! i have never tried that weight before and i was very impressed with myself. He proceeded to go to about 620lbs and i said that 540lbs was enough. In actuality, it was 585lbs due to the weight of the sled. I only count the weight that i place on the machine.