It's been a while since I took Physics in college and I have a simple gravity-based question that should be really simple for this forum. Two of my friends are having a disagreement over the difficulty of doing a pushup. One claims it is harder to do a pushup when your hands and toes are on the floor and the other claims it is harder when your hands are on an aerobics step which puts them a 8 inches above the toes. I tend to agree with the latter position but I don't know how to prove (or disprove it). This seems like a work calculation based upon the angle of the person while elevating his plane upward at one end. Any help would be appreciated.