My bunghole
The answer depends on which 40-yard line. If you're on your own twenty and run to your own 40, you ran twenty yards. If you start from your own twenty and run to your opponent's 40, you ran forty yards.
to my learnings i think he ran a 4.97 in the 40
he ran 40 yards in 1 second.
he ran a 4.521 40 yard dash
Danny Woodhead ran a 4.31 on his 40
He ran a 4.16 unofficial 40 yard dash at his combine.
He ran a 4.4 40 yard dash
-40
He ran the 40 in 4.38s http://en.wikipedia.org/wiki/Ladanian_tomlinson
4.40
Chris Johnson
4.38 is the best 40 he ran