The forward rotation of the spine refers to the direction and movement that takes place in the upper body during the launching phase, which is forward, toward the pitcher. See Figure 4-22.
If you recall during the loading phase back on page 11, we talked about the backward rotation of the spine, and this was where the chest, abdomen and entire upper body were all turned back toward the catcher as seen from behind home plate in Figure 4-23.
In that section, we identified the muscles responsible for this movement as the lateral rotators of the spine on the left side of the player’s body. Specifically, their names are the External Abdominal Oblique, Multifidus and the Rotatores Spinea muscles. See Figure 4-24.
Now the contraction of these muscles on the players left side during the loading phase caused the lateral rotators of the spine on the players right side to stretch. And it is now, during the launching phase, where we can see the effect of these stretched lateral rotators of the spine on the right side of the player’s body.
Notice how at the beginning of the launching phase shown in Figure 4-25a, we cannot see the player’s number, but as he begins to swing, his entire upper body is turning so that at contact, his number is completely visible as seen in Figure 4-25c.
This turning of the spine and upper body is a direct result of the contraction taking place in these lateral rotators of the spine on the player’s right side and again, their names are External Abdominal Oblique, Multifidus and Rotatores Spinea muscles. See Figure 4-26.
So now, if we look across home plate, as the hips begin their explosive rotation toward the pitcher and torque is building across the pelvis (Figure 4-27a), this ever increasing rotational hitting power source (Figure 4-27b) is also being combined with the contraction of the lateral rotators of the spine on the player’s right side (Figure 4-27c).
This intense buildup of speed and power in the lower body and upper body helps pull the arms around to deliver a quicker, stronger and more dynamic rotational bat swing.
In the next section we will talk about the fourth noticeable movement during the launching phase, which is the pushing and pulling action of the arms and shoulders, and identify the muscles involved with it.
