The article brings up some interesting points, and I have wondered myself how modern man stacks up against his ancestors.  I can more or less believe the claims that are made, given the lives of physical labor that many of them lived beginning at an early age.  But there were trade-offs – shorter lifespans, lack of literacy and other education, etc.  What's interesting is that the rulers of previous ages may have lived rather sedentary lives, and so generations of this would have produced soft and weaker men.  The physical contrast between them and the hardened warrior-soldiers would have been all the greater.