I occasionally hear reporters and commentators (usually in politics) in the US speak of someone being “on the back foot” by which they mean on the defensive. This always takes me by surprise since, although it is an idiom that I am familiar with, it comes from cricket, a game that few Americans have even the faintest idea about.
Its origins lie in the fact that a cricket batter who steps forward to meet the oncoming ball (i.e., plays it “on the front foot”) is seen as being aggressive, advancing to meet the attacker (the bowler) and taking greater risks since they are reducing the time available to decide how to play the shot. Here is Joe Root, the cricket captain for England, demonstrating one front foot shot.
Those who draw back after the ball is delivered (i.e., play it “on the back foot”) are seen as being on the defensive, as demonstrated below.
It is not a perfect metaphor since after moving forward, the batter might decide to play a defensive stroke and just stop the ball. Conversely, after drawing back, a batter might hit the ball aggressively and hard in an attempt to score runs. Here is an example of the latter.
There is a bit of linguistic subtlety here to distinguish between a defensive back foot shot and an aggressive one. If the player hits an aggressive shot while drawing back, he is said to have hit it “off the back foot” and not “on the back foot”.
If you thought the game of cricket was complicated, the vocabulary and language used to describe it it is even more bizarre.
I looked up the idiom to see if there is something in American life that might have generated it but it appears not. It has been imported from cricket, though I am not sure how many of the people who use it are aware of its origins. Somehow, it got unmoored from its source and sailed freely across the ocean to take up a new home in American English.