Originally posted by 49ersMyLife:
He is starting from still position...and he is a big guy with long strides - you gotta take both of those things in account, which will slow down his 40 time.
^^^ Yup. Bolt's worst part of his run is his start. Being 6'5, he doesn't get out of the blocks well. That 9.58 run was his best start in a while, and he still came up too fast. Sprinters have to stay low and come up gradually out of the blocks, which he didn't do. Basically, Bolt's first 40 meters are the worst 40 meters of his race.
That said, he'd still probably run around 4.05 or something.