A batter is said to swing for the fences when he makes a very forceful attempt at a pitch, often featuring a start of his swing from an extreme cocked position and finishing in an exaggerated turn. Batters usually swing for the fences when they sense that their team needs a home run in a given situation.
Batters who swing for the fences either do so according to the situation or due to habit. Some hitters seem to swing for the fences during every at bat, disdaining any idea of a short swing and whirling around with all of their might, often called swinging from their heels, referring to the starting and ending point of the swing. Obviously, some hitters have earned the right to swing for the fences in given situations. They make contact, are proven home run hitters and know when their team needs a lift. The worst case scenario for a swing for the fences hitter is a low-contact singles hitter who thinks that he is a home run hitter. This results in many more strikeouts and lower production. Such hitters are often encouraged to shorten their swings and use the entire field to have hits fall in.