Inside the park home run
From BR Bullpen
An inside-the-park home run is a home run that does not leave the park by clearing the outfield fence. It is often hit by a very fast player but not always. Usually the ball needs to be misplayed by an outfielder without committing an error allowing the hitter enough time to circle the bases.
Before the 1920's, however, when fences were much further away from home plate than they are today, inside-the-park home runs were more common than those that left the ballpark. This trend ended with the end of the Deadball Era and today, inside-the-park home runs have become quite rare, occurring on average fewer than 20 times per year in Major League Baseball.
