Hit the Ground Running

There is no disagreement about the meaning of the expression, which is to seize an opportunity by beginning at full speed. However, Dictionary.com says the origin is disputed. “It may come from combat troops dropped into a combat zone, from stowaways jumping off a freight train as it nears the station, or from Pony Express riders avoiding delay when they changed mounts.” All create a vivid mental image, so I don’t have a favorite.