"Obviously, players in pads can’t run the same speed as a world class sprinter coming out of blocks but their acceleration curves have the same shape. They get up to around 80% of their top speed relatively quickly, but the last 20% is stretched out further (it takes the Olympic guys around 60 meters to hit 100% of their top speed). Once I had the curves created, I tuned them around combine 40 times and 100 meter times of players who ran track in college. I then passed that info on to Ratings Czar Donny Moore so he could set speed and acceleration accurately for our rosters. In total, we have 24 different curves that we can tune to control everything from how a player's speed increases over time (based on acceleration and speed ratings), to how much he can turn based on his current speed (driven by the agility rating). That level of control really lets us differentiate players on the field.
It is now possible for our ratings guys to make players that are quick over 10 to 20 yards, but get smoked at longer distances. A 90 speed player can now run the same 40 time as a 99 speed player, but lose over longer distances. I have a video here to highlight this. I created two players. The first is 99 speed, 90 acceleration (#99, on the top in the video). The second is 90 speed ,99 acceleration (#90 on the bottom in the video). The players race for 90 yards in the video. As you can see, the player with higher acceleration jumps out to an early lead, but gets passed at around 40 yards by the higher speed player. The animations aren't final (particularly the initial move that plays), and I still have some fine tuning to do on how we map the acceleration and speed ratings into our set of curves, but you can see how powerful acceleration is going to be in Madden NFL 11."
