Do people run 40 yard dashes to decrease their 40 time or is it simply used as a test/measure of speed?

Question

e.g. do football players like Reggie Bush actually practice running 40 yard dashes or do they do other exercise/weight training that can help their 40 time?

Answer 1

Both

Wearing a "parachute" trainer, pulling a sled, running stairs are also ways to work on your 40 time by building quick muscle against resistance.  

Answer 2

well the 40 yard dash is used to see how fast people are but ya if u do it over and over agian it would work but they do other things like lift weights and go on long runs  

Answer 3

We do run 40's not only to get faster, but to get better at explosion and form. But 40's are just one of the many distances players run at to get faster and better. The reason the 40 is so accepted is because it measures explosion and acceleration, which is important in football.

Answer 4

Thats a good question. I would say they try to improve by running it over and over but thats a good question.