I wasn't writing about football skills of course, I was writing about measurable physical attributes like strength, footspeed and the like. In another analogy, basketball requires certain physical attributes to "go pro". The sharpest shooter isn't going to make it if they're slow of foot and five foot eight. IQ tests measure the ability to solve certain types of problems, to make correct analogies, and as Isaiah pointed out, IQ scores don't change much from childhood on. As you point out, only certain mental skills are measured, or at present measurable, and there are many others to consider;)