Rotation is a common word heard now in baseball and softball. In this post, I want to go over what exactly this means and how it relates to mechanics.
The internal and external obliques are part of the core and connect from the ribs to the pelvis. While the main function of the core is to stabilize, the obliques contract causing the body to rotate. Even though the pelvis and the ribs are connected, they do not need to rotate together. When the ribs and pelvis do rotate together, rotational power is decreased. From the ground up, the pelvis rotates slightly ahead of the ribs, creating an elastic movement increasing rotational power. A common misconception is that opening the front hip early zaps power, but if the ribs stay closed an explosive torque occurs.
Note the difference between when Stanton and Pujols ribs start to move and when the pelvis starts to move. They do not rotate at the same time.
In the top video, before cuing and drills, Joe steps to his right and punches into the resistance of the elastic band. Note how both his pelvis and rib cage rotate at the same time to the right bringing his left hand along for the ride.
In the bottom video after cuing and drills, Joe steps to his right but lets his right knee rotate and open, while his hip, pelvis, and ribs stay closed. Then, his R hip opens followed quickly by his pelvis followed quickly by his R ribs, and finally his fist.
Remember from the description above, we want joints to rotate from the ground up slightly behind the joint below. Therefore, Joe's left fist has less energy once it gets to full reach (top), while having full energy and whip (below). Translating to baseball/softball the ball is thrown faster or the ball is hit harder.
What is also great to see is that both videos finish in the same position. To the naked eye in real time Joe would appear to be doing the same motion. Please look at mechanics with slow motion video.
Here is another short clip of Joe this time to demonstrate how rotation is used in the throw as well. This will create delays in the throwing motion to allow for proper timing and transfer of force up through the body. Stay tuned for upcoming posts.