Generally speaking, the peak of a male athlete's abilities comes at around age 29-30. This is almost never true for NFL players because they get beat down so hard through their twenties. Freddy managed to make it to his peak years without getting worn out.
It's called Old Man Strength, and it's for real. As an avid skier, cyclist, and swimmer I can say that the last few years (age 30-34) I have felt stronger, more balanced, and fitter than ever before with no additional effort. And that's on two rebuilt ACLs!