duckhunter returning fire:
The empirical data would support the generalization; however, empirical data doesn't always tell the whole story. Relativism would suggest factors both supporting and opposing the general supposition. I provided one anomaly, Reggie White, that inferred the supposition is in doubt based off a purely empirical data point-timed speed. Also, provided a factor concerning track surfaces and running times might suggest the measuring instruments as inaccurate or more correct inconsistent on a relative basis. The changing nature of the game from run first to predominantly a passing league would require the need for and supply growth of different types of athletes to meet the changes. Nutrition, training-particularly strength and more quick twitch needs as opposed to longer speed and immediate demand strength versus lessening endurance priorities as seen by the use of more rotational and specialist players. The list goes on and on.
After all is said and done, I think many times we are comparing apples to oranges in the final analysis. So much for a simple game.