A foot race has always been my get out of jail free card.
In most circumstances, everybody assumes that someone of my size (6 foot 5 and 295lbs) is uncoordinated and slow. So there were numerous times that I would find myself down in action, and I would offer double or nothing in a foot race.
The only restrictions were, you cannot cross paths (blocking), or touch the other person in anyway (including bystanders).
I would always step it off, and the race was between 50 and 60 yards.
I have not clocked it in a long, LONG time, but in college, I ran a 4.6 second 40 yard dash, and since I am now older and fatter, my guess is I would probably run a flat 5.0. This is why I run 50-60 yards instead of 40. It allows me a few extra steps to get up to speed, as being fat makes getting of the line hard LOL.
I tried 100 yards a couple times, but end up slowing down... again because I am fat LOL.
overall I am probably 13ish (plus or minus a couple) to 2 on the footrace bet.