Bo Jackson had a hand timed 40 yard dash time of 4.12 second in 1986.
It is average.
The average 40 yard dash speed for an CB in the NFL is 4.25 to 4.45
Because they dash for 40 yards.
40 yard dash/10 yard dash= 4 What ever the time you got for the ten yard, you multiple it by 4. It could be an average of your running time per 10 yard dash. Sometimes for several runners, they would feel worn out by the time when reaching the 40 yard mark.
Based on combine results from 2000-2017, the average speed of a Strong Safety in the 40 yard dash is 4.55 seconds.
4.75 40 yard dash.