What is the origin of the idiom "on the ball" and when to use it?

The origin of the idiom "on the ball" can be traced back to sports, particularly ball games such as soccer or basketball. In these games, being "on the ball" refers to a player who is actively engaged in the game, attentive to the ball's movements, and ready to react quickly. Over time, the expression began to be used to describe individuals who exhibit a similar level of alertness, attentiveness, and readiness in non-sporting situations.