hit the ground running: get a head start on an activity or or start it without advance preparation
The first uses of this phrase were literal, as in this quotation from the Sandusky Register (Ohio ) for April 30, 1895: "The bullet went under me. I knew he had five more cartridges so I hit the ground running . . ." The expression was also used figuratively from the beginning of the twentieth century. In The History of Alabama and Her People, published in 1927, the author writes of a local candidate who "hit the ground running" in the 1918 election.
Several explanations have been put forward for this phrase's origins, but most come too late in time. For instance, some people claim that the expression originated with World War II paratroopers who were dropped behind enemy lines. Others have proposed marines who hit the beach from troopships or soldiers who jumped into combat zones from hovering helicopters. None of these explanations takes into account that hit the ground running is found in print from the late nineteenth century.
A better idea is that hit the ground running was inspired by stories of the Pony Express. During 1860 and 1861 the Pony Express carried mail between St. Joseph, Missouri and Sacramento, California. The company boasted a 10-day delivery, about twice as fast as other overland services. Riders changed horses every 10 miles and most could switch over in a matter of seconds. To accomplish this feat, they really had to hit the ground running. The phrase might have been in general use in the West, where cattle herders, soldiers, and others often needed to dismount fast. The high profile of the Pony Express could then have popularized the expression with folks back East.