http://www.aaa3.net/how-to-scale-agile/

What is the difference between agility and acceleration when it comes to how fast someone runs?
Like for instance in the game Madden NFL 2010, I created a football player. In his statistics column, it asked me on a scale of 0-100, how greatly he can accelerate, then it asked me how agile he could be. What is the difference?
Great question. How agile you are is more like how quickly you can adapt and adjust your direction, like flexibility and reflexes, in relation to your speed and surroundings. If you’re still not sure what I mean, look up a similar word like nimble.
It’s all very well to be able to run 40 metres in 5 seconds, but if you take off and after 3 seconds a cow walks in front of you and you can’t dodge it in 2 seconds, that would suck for you. If a Wide Receiver can be 50 yards down a field in a few seconds, that’s great, but if there is a Cornerback in his way or the ball changes direction slightly because the Quarterback is hit while he releases it or it is tipped slightly and the Wide Receiver cannot change direction and speed as he needs to, his Acceleration alone did not do much good without Agility. I think I’m just about quick enough but even more agile, and I like it that way, but obviously it’s also good to be just about agile enough but even quicker. Either way, don’t think that one without the other will ever make a good player.
Agility is really a mind and body relationship, muscle memory, more Biology and Psychology than it is Physics. It would be easier to compare Speed (how much Distance in how much Time) and Acceleration (how much Time to cover how much Distance in how much Time) in terms of physics, but it would just be the same concept: balance them both according to the player’s position.
Agile Development Teams: Scope and Scale with Mike Cohn