SPEAKER_02 53:56–56:51
And so that also creates a downward force into the ground through the knee. This magnifies that internal rotation into the ground. A tremendous amount of downforce is required to create the wave of internal rotation that goes up into the extremity. We are always superimposing this internal rotation on top of this external rotation position. As the wave of internal rotation goes up through the body, an expansion follows behind it. When landing in this early propulsive position, we've created a delay strategy on the lead foot to allow the throwing side, the throwing arm, to translate ahead of that lead foot. That ER wave is the delay that comes right behind the high force. For a right-handed thrower viewed from the right side during a throw, you should see the right hip start to translate ahead of the left. It's like your left back pocket stays back while your right back pocket goes forward. You'll see this go up into the lower back, showing that delay strategy on that side as the right side translates forward. If you don't see the delay strategy, both sides are trying to move together with no differential, reducing throwing velocity. With no differential, you have a longer distance to travel because the whole pelvis turns as a unit, going around the left lower extremity instead of straight through it. To maximize velocity, you always want the straightest line toward the throwing direction. When planting the left foot and capturing that early propulsive strategy, the sacrum moves backwards on the ilium, creating expansion on the left side while the right side goes through its movement, which is where velocity comes from. I have to slow the left side down to let the right side go forward. If both sides try to go forward simultaneously, it's no longer a straight line but a longer curve. For the right foot to land and translate forward, I must create the delay here. As I step forward with my left foot, my foot isn't on the ground yet. When the foot hits the ground, there must be a quick turn; the sacrum has to turn toward the lead leg. As I step forward with my left foot and the ball is behind me, my hip does the exact same thing. As I reach forward with my left arm to throw, my hip goes forward. Upon landing and pulling the arm back, the sacrum turns toward that side. Both the upper rib cage and the pelvis face the same direction at the same time as they turn. Then, as the ball is pulled through, that side goes forward. This mirrors the shoulder blades doing the same thing.
kinetic chainpropulsion mechanicspelvic differentialdelay strategyinternal/external rotation