DAYTONA BEACH, Fla. (AP) — The pain was real.

Some 48 hours after being put through Danica Patrick's fitness test by Danica Patrick herself — it's the basis for her upcoming book and the sort of thing that will occupy her time when retirement from racing comes — I wasn't constantly sore. But every time I stood up came a sharp reminder from my legs that Patrick had kicked my butt.

This was the workout: 100 air squats, 100 push-ups (on my knees), 100 butterfly sit-ups and 100 lunges, all timed to see how long it took to complete the set. That's the benchmark for more than 700 participants in the...