The whole body is involved in a baseball swing, with legs, forearms, wrists, abdominal muscles, hips and lower back muscles playing the most important roles, according to Bob Alejo for BodyBuilding.com. Hitting coaches concentrate on strengthening these and other muscles with weight training, calisthenics and resistance-based exercises.
Because the key to a good baseball swing is the speed of the bat head through the hitting zone, conditioning coach Bob Alejo recommends resistance-based training. He says that exercises that rely strictly on body weight resistance are inadequate for developing maximum bat speed. For upper abdominal muscles, Alejo suggests adding weights held at arms length while laying on the back and completing three sets of 10 to 20 repetitions. For lower abdominals, the preferred exercise is hanging leg raises with weights attached to the ankles.
The second area to work on is leg strength. The strength of the legs determines the ability of the abdominal muscles to generate bat speed. There are also eight hip muscles involved in the swinging of a bat that, when combined with spine rotators, are the primary source of power when swinging the bat. Finally, the forearms and wrists guide the bat into the proper position in the hitting zone. Alejo recommends concentrating on grip-related exercises like squeezing tennis balls, racket balls and softballs. These exercises strengthen fingers, hands and the overall grip.