I daresay race is irrelevent to what you're talking about.
What you're listing is the attributes of smaller athletes.
What most of the African American players do have in bucketloads is fast twitch fibres that are superior to your white guy.
They have ridiculous explosive power.
And yeah I had Sproles in mind too,which is why I laughed at people saying Carney is too short to play RB.
But yeah he hasn't got nearly enough agility.
i reckon the flexibility that im referring to is as much of an asset to them as their speed. but generally, they can put on the breaks too....watching them get their hips as low as they do, turning and weaving, then flicking the switch from a standing start is quite a sight.....athleticism at its finest.
cant think of many white boys who are currently playing the HB role at any club.........Justin Fargas is mixed race, and Jacob Hester went through college as a HB, but is used mostly as a FB with the Chargers. Nick Goings from Carolina is the last white fella i can think of who got regular snaps as a HB, and that was a few seasons ago.
its quite interesting how most positions are dominated by race in american football. Kicker, Punter, QB, and many on the offensive lines are predominantly white. RB, WR, and defenses are predominantly black. there's probably an even spread at TE and FB.