This is a nice article that I have come across before. Thanks for sharing it.
In
another discussion related to comparisons of Cook to Fournette, the point is made that running a higher speed at a greater weight causes that player to generate more momentum, thus making it more difficult to slow that player down when tackling them, which could lead to more yards after contact.
On a related note Jerrick McKinnon has reportedly added 10 lbs during this offseason, I presume with the goal of enabling him to improve in this area (yards after contact) that Mike Zimmer wants from him.
However as we can see from the charting data in the link above, Cook has consistently gained more yards after contact per attempt than Fournette has. So clearly there is more to gaining yards after contact than weight or a speed score than combines 40 time with height and weight.
What Cook does that I really like about him is that he never provides a very good target for tacklers to bring him down, and this leads to more yards after contact, sometimes a lot more yards after contact due to his speed to gain large chunks of yards after making a defender miss. I also think he is better at breaking tackles than people give him credit for. It is more subtle than how Fournette does this, but as we see from the charting data, actually more effective on a per touch basis.