To help you see these three actions in effect more clearly, let’s take a look back to the beginning of the launching phase, but this time from behind home plate.
Here we are at the beginning of the launching phase and we see that the starting position for the right hip is flexion, the starting position for the right knee is also flexion and the starting position for the right ankle is dorsi-flexion. See Figure 4-15.
Now let’s compare this figure (Figure 4-15) showing the start of the launching phase with the previous one (Figure 4-14) at the point of contact with the ball. See Figure 4-16.
At contact we now see that the right hip has extended from its starting position and you can see this just by comparing the angles at the hip in Figure 4-16. The right knee has also extended a little from its starting position and the right ankle has plantar-flexed from its starting position.
Now keep in mind that the right hip is not in complete extension, the right knee is also not in complete extension and the right ankle is not in complete plantar-flexion however, these are the actions, or motions, that are taking place in these three joints all the while the hips are opening toward the pitcher and they contribute incredible lower body strength and power to the swing.
Now, the muscles involved with hip extension are the Gluteus Maximus and the hamstrings muscles which are the Semimembranosus, Semitendinosus and the long head of the Biceps Femoris. For the record, the hort head of the Biceps Femoris does not cross the hip joint and is therefore not considered an extensor of the hip. These muscles can bee seen in more detail in Figure 4-17.
The muscles involved with knee extension are the Quadriceps muscles, or more specifically, the Vastus Medialis, Vastus Lateralis, Vastus Intermedius and Rectus Femoris. These muscles can be seen in greater detail in Figure 4-18.
And The muscles involved with ankle plantar-flexion are the calf muscles which include the Gastrocneumius and Soleus. These muscles can be seen in greater detail in Figure 4-19.
Now as the player’s back right hip is rotating and opening toward the pitcher and this same right leg is further driving or pushing, the players front left leg is stiffening and the knee starts to extend or straighten out. See Figure 4-20a. This stiffening and straightening of the left knee and leg produces a force in the left hip acting in the opposite direction as the right hip. See Figure 4-20b. As a result, a short, compact and explosive pivoting action across the player’s pelvis is created that carries up the spine. See Figure 4-20c.
Here’s another look at the straightening of the left knee and leg from down third base line. Figure 4-21a shows the swing just past the point of contact and we can again see how the straightening of the left knee and leg forces the left hip backward, in the opposite direction as the right hip as seen in Figure 4-21b. Again, this creates a short, compact and explosive pivoting action across the player’s pelvis that carries up the spine. See Figure 4-21c.
The combination of the hips exploding open toward the pitcher, along with the massive torque created across the pelvis by the pushing of both legs in opposite directions through contact, is the primary source of power in the player’s swing.
In the next section we will talk about the third noticeable movement during the launching phase, which is the forward rotation of the spine, and identify the muscles involved with it.
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