If you're looking for colorful language, there's no better place to start than the wide world of sports. Recently I heard casters for a League of Legends game saying that one team was definitely "on the back foot."
Since it was clear that the team in question was losing, I could surmise that "on the back foot" was not a good position to be in. But more to the point, what exactly did that mean?
As with many English idioms, no one has a definitive answer. However, the most likely explanation comes from boxing, where being "on the back foot" means that the fighter is in a defensive position, rather than the more aggressive offensive stance. It's also possible that the phrase comes from cricket, where "on the back foot" suggests that a player is protecting his territory.
Of course, a more familiar idiom is "backpedaling," which clearly implies a hasty retreat.
I love looking up the origins of phrases. Sometimes there are shades of meaning that only become apparent when you know the background behind the saying. In this case, "on the back foot" seems much more clear to me now that I know where it came from.
Have you ever heard this term? What did you think it meant?
Here's a link with more information: http://www.wisegeek.com/what-does-back-foot-mean.htm