Without having read the primary one, the SBS article seems to indicate that average fitness levels are dropping across the generations, which I would not dispute at all.

What I would challenge though is that the top 1% I reckon would be on par or exceeding previous generations. Advancements in sports science, technology, understanding of the body etc as well as the ramping up of professionalism allowing more people to more fully dedicate themselves to athletic and sporting pursuits. I dunno, I just find it hard to imagine that blokes who have busted their gut since they were 10 under modern training regimes and coaching would fall short of blokes who spent more time surfing and riding bikes.