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[OC]How 40-yard dash result translated to 100 sprint time?
After NFL combine every year there will be some fans arguing how players can perform in 100m sprint race. Also, fans will also argue what is the real 40-yard dash record ran by Bo Jackson when there is electronic timers.
Therefore, I do some researches on how the time split of 100 meter sprint athletes can be related to a short distance run. I am using the result of 100 meter Man 2009 Berlin Championship Sprint where Usain Bolt broke his world record 9.58s here (data can be retrieved
here).
Normally a 100m sprint athlete reach his top speed at around 50m, consider the acceleration of athlete is changing it is hard to compute a very accurate result. Fortunately the 20m time split of athlete is highly linear (
Graph of some athlete's 20m split and their R2 value are often 0.999 or higher). It is due to elite athlete reach their 90% speed near 20m and the acceleration and deceleration is small compare with their speed (Speed of medal winner can be found
here).
As the graph plotted above the slower athlete tends to have a more gentle slope and smaller y-intercept in their 20m split graph. Therefore, by comparing the slope and intercept we can find how their time for short distance change with their 100m time.
By using all available time in 2009 Berlin Championship relationship of their slope and intercept is plotted as below.
Slope
Y-intecept
However, the error will accumulate when the athlete is slower.
Error in 100m time
To tackle the problem I use estimated 100m time to normalize the estimated time to actual 100m time in order to make it more accurate.
This is the excel file which consist all the data and graphs.
It has a calculation tools to calculate 40-yard dash time out of 100m time. Be careful that the data will be extremely inaccurate after 13s 100m [so it cannot use for calculate a 19+ 100 meter time like me and sadly slower than at least half of the girls in my high school
]
A quick convert or tl;dr of the calculation
| 100m time | Estimated 40-yard dash |
|---|
| 9.79 | 4.2 |
| 10.27 | 4.3 |
| 10.64 | 4.4 |
| 10.95 | 4.5 |
| 11.21 | 4.6 |
| 11.45 | 4.7 |
| 11.73 | 4.8 |
Finally it is some comparison of NFL player time and estimated time (Note that NFL combine and 100m sprint is running on two types of floor and 100m sprint time is their best time, so small variation is expected). As players compete much more times for their personal best, feel free to add ~0.05s for more probable calculation.
| NFL player | 100m time | 40-yards dash | Estimated time | Difference |
|---|
| Chris Johnson | 10.38 | 4.24 | 4.327511 | -0.08751 |
| DeMarcus Van Dyke | 10.61 | 4.25 | 4.390455 | -0.14045 |
| Dri Archer | 10.49 | 4.26 | 4.35658 | -0.09658 |
| Jerome Mathis | 10.49 | 4.26 | 4.35658 | -0.09658 |
| Jacoby Ford | 10.32 | 4.26 | 4.312426 | -0.05243 |
| Jeff Demps | 10.01 | 4.26 | 4.242679 | 0.017321 |
| J. J. Nelson | 10.49 | 4.28 | 4.35658 | -0.07658 |
| Brian Witherspoon | 10.22 | 4.29 | 4.288456 | 0.001544 |
| Darrius Heyward-Bey | 10.3 | 4.3 | 4.307516 | -0.00752 |
| Josh Robinson | 10.77 | 4.33 | 4.439304 | -0.1093 |
| Tye Hill | 10.27 | 4.34 | 4.30026 | 0.03974 |
| Michael Huff | 10.13 | 4.34 | 4.268097 | 0.071903 |
| Travis Benjamin | 10.4 | 4.36 | 4.332659 | 0.027341 |
| Devery Henderson | 10.4 | 4.36 | 4.332659 | 0.027341 |
| Roy Williams | 10.3 | 4.36 | 4.307516 | 0.052484 |
| Brandon Banks | 10.42 | 4.37 | 4.337867 | 0.032133 |
| C. J. Spiller | 10.29 | 4.37 | 4.305083 | 0.064917 |
| Reggie Bush | 10.42 | 4.38 | 4.337867 | 0.042133 |
| Jamaal Charles | 10.23 | 4.38 | 4.290788 | 0.089212 |
| Andre Johnson | 10.59 | 4.4 | 4.384648 | 0.015352 |
| Joe McKnight | 10.59 | 4.4 | 4.384648 | 0.015352 |
| Lamar Miller | 10.56 | 4.4 | 4.37606 | 0.02394 |
| T. J. Graham | 10.21 | 4.41 | 4.286138 | 0.123862 |
| Devin Hester | 10.42 | 4.41 | 4.337867 | 0.072133 |
| Cordarrelle Patterson | 10.54 | 4.42 | 4.370415 | 0.049585 |
| Denard Robinson | 10.44 | 4.43 | 4.343137 | 0.086863 |
| Average | 10.39577 | 4.340769 | 4.333608 | 0.007162 |
