Let me take you on a journey through the biomechanics of pitching. Most people understand that power comes from the lower half when throwing a baseball. So what workouts do you do for the lower half? Squatting, deadlift, leg press, etc? I would argue that these exercises are unnecessary if you are trying to gain velocity when throwing a baseball. With this being said, these exercises are very important for overall function and hormonal response, just not going to make you throw harder.
Let’s start with the leg kick. The point of a leg kick is to allow time to pass as forward momentum is being built. Arm separation has had time to occur while the leg has come down. As the front leg extends toward home, THE MOST IMPORTANT thing in a pitching motion happens. Most of your power comes from how quickly you can rotate your pelvis toward the home plate. As your front leg comes down you create an external rotation of both legs. Just before the front foot hits the ground, relative internal rotation occurs in both legs. The front leg uses internal rotation to rotate the pelvis toward the home plate while the back leg maintains internal rotation to translate centripetal force toward home plate.
Let’s move up the chain… This quick and powerful rotation of the pelvis induces a stretch on the anterior oblique muscular sling. This is comprised of internal obliques on the glove side and external obliques on the throwing arm side. Pectoralis major, biceps long head, and flexor digitorum superficialis on the throwing arm side has induced stretch through the centripetal force as well. Picture a slingshot being cocked back. The rest is firing of the muscles that have now been stretched.
The point of all the biomechanics is to understand that simple leg workouts will not help your athlete gain velocity. The questions you need to be asking are: How do I train power and speed behind hip internal rotation? How do I train comfortability in internal rotation on the stance leg? How do I train my core to be able to transfer load from my lower extremity to my upper extremity?
The dissonance between training and games needs to be closed. I take a special interest in the biomechanics of athletes because I understand how devastating injuries can be, especially unnecessary injuries. I tore my UCL while pitching because I had certain biomechanical flaws that were not addressed. The Rehab Docs understand how important it is to build strength, power, and speed off of foundational movements of each sport. Don’t waste your time and energy training inefficiently. Different sports require different types of training to make sure you are maximizing your potential and limiting your risk of injury.