Posted by Victoria S Dennis on March 04, 2006
In Reply to: "flat out" posted by Gary Martin on March 04, 2006
: : strange that the writer of the page would use the term "flat out" when discribing "balls to the wall" yet leave us with no explanation for "flat out".
: I've removed that page now, as I can't substantiate that origin. Flat out just means, "as fast as (or with as much effort as) you can go".
I think it is a metaphor from a horse going at full gallop. The legs stretch out in front and behind at each pace, and the animal as a whole looks flatter and closer to the ground than when it is going at a gentle speed.