But, is that correlation also causation? By which I mean, are they that strong because of that volume (personally I think it has a lot to do with it, but it could hypothetically be a coincidence, is all I'm getting at)? Perhaps they use that much volume because they love lifting weights, and they love lifting weights because they're strong. Perhaps their love of lifting is what keeps them coming back for more year after year, getting stronger along the way, and the volume is an irrelevant fact. Just throwing out some hypothetical possibilities.