What is the most important drill at the combine?
The 40 yard dash.
There is not a single more intimidating drill in professional football. You can drop rounds and maybe out of the draft with a bad 40. But your stock can rise with a good 40 time.
Some teams put more emphasis on 40 time (cough, cough...Raiders), and some teams don't put as much of an emphasis.
But there is one thing for sure. A player's draft stock can rise to Everest and fall all the way back down in a matter of four to five seconds.
So, I've searched on how players can run a better 40 time.
Decrease the reps; put more emphasis on weight
This is to increase their explosiveness.
Use long strides
Longer strides help a lot better than short quicker ones. For example, look at Ohio State QB Terrell Pryor. Whenever you watch him, you wonder why is he so quick. But then when you slow the video down, you see the long strides he takes.
Improve the hip flexors
This greatly improves agility.
Improve basic mechanics
These are just things like pushing off well and maintaining a good stance through the sprint.
Here are some notables from the past two drafts that have significantly improved their stock with a good 40 time:
WR Darrius Heyward-Bey (4.30)
RB Chris Johnson (4.24)
CB Alphonso Smith (4.41)
WR Johnny Knox (4.34)
Some notables that have had their stocks drop significantly are:
ILB James Laurinaitas (4.84)
WR Austin Collie (4.55)
WR Mohammed Massaquoi(4.57)
RB Shonn Greene (4.63)
For some players, it might mean an NFL career. For others, it's just a major disappointment.
Either way, it should be interesting to see.