Question

If an athlete were somehow scaled up proportionally to twice the original size, would he be stronger or weaker?

Answer 1

Well for starters every dimension is doubled, so mass and weight increase eightfold. Thus said athlete would become eight times as strong. He would be able to jump twice as high and run twice as fast. One major downside is that with eight times the weight but only four times the cross sectional area, all of his joints and bones are now subjected to twice the amount of stress (lb/in^2) when standing compared to his life-size counterpart. He would likely develop serious health problems before long due to these stresses. So yes, he would be stronger, but not for very long.