LOL, so if a fighter wants to hit hard he just needs to invest in a heavier heavy bag? Why not just put a mattress against a solid wall? Would that be the ultimate in making a fighter hit hard? Most gyms used to have a variety of heavy bags, some smaller so the fighter would have to move and punch, some bigger so a fighter could just practice punching without having to move much. All fighters of all sizes used all of them and it was not viewed as a feat of power or strength to use the bigger bags. Today, many gyms have those heavy bag racks where the bags are close together, are attached at about 8' and have little movement. I still prefer bags that hang from a high ceiling and have a long chain. They'll move some whether they are 100 pounds or 300 pounds and the fighter has to move to hit them. But the building has to have a high ceiling. The size of heavy bags is just a preference and is often times dictated by how high the ceiling in the gym is, how much room there is for heavy bags, etc. Until I read some posts on this board I never realized that some people think using a heavy, heavy bag is a feat of power and strength.