That there is the world record progression for the men's 100 meter sprint, from 1912 to the present day, from Wikipedia. As you can see, humans got faster by nearly a full second over the course of the century. In almost any measurable athletic test, humans perform better now than we did a hundred years ago.
To what can we attribute this? Better diet? Smarter training? Better timepieces? And more importantly, where's the performance ceiling?
According to a French study in the Daily Telegraph, humans will hit their performance limits around 2060. "We are reaching the limit in terms of physiological capacities of the human race," says French researcher Jean-Francois Toussaint. After that it will be goodbye steroids, hell-o cybernetics! But with any luck The Bionic Woman, both the old and the new one, will be forgotten well before then.