We all know that sports records keep getting broken, but we generally don't appreciate just how dramatic the progress has been, or the reasons for it. For example, the Olympic records of a hundred years ago—representing the best performance of any human being on the planet—today in many cases equal ho-hum performance by high schoolers. The winner of the men's 200-meter race in the 1908 Olympics ran it in 22.6 seconds; today's high school record is faster by more than 2 seconds, a huge margin. Today's best high school time in the marathon beats the 1908 Olympic gold medalist by more than 20 minutes. And if you're thinking it's because kids today are bigger, that's not it. Recent research by Dr. Niels J. Secher of the University of Copenhagen and others shows that size is no advantage in running, since each stride requires you to lift yourself up. “The smaller you are, the better you are,” he says.
In any case, events in which size and power are irrelevant show the same patter of constantly rising standards. In diving, for example, the double somersault was almost prohibited as recently as the 1924 Olympics because it was considered too dangerous. Today, it's boring.
This matters because of why it's happening: Contemporary athletes are superior not because they're somehow different but because they train themselves more effectively.
— Via Talent Is Overrated