re: What would Usain Bolt's 40 yard dash time be?

quote:

---

Bolt reached 40m in 4.64. The timing for NFL 40y starts when the athlete makes their first movement (correct?). To adjust Bolt's time toward the NFL time, you would subtract his reaction time, .146, which would bring him to a bit under 4.50 for 40 meters.

You would add .24 to all of the NFL guys' times since they are not using fully-automatic timing. That would put Chris Johnson at 4.48 for 40 yards, which is less (considerably) than 40 meters.

---

...and in your opinion what are the effects of the starting block vs. no starting block and running on a track vs. running on field turf?