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Understanding the kinematic sequence is massively important to players and coaches as it’s the cornerstone for effective pitching. To learn more about the kinematic sequence, start with this episode of the More Than Velocity Podcast, where we break down the details.
Now, to look at rotation in more detail, biomechanists evaluate the kinematic sequence. Essentially, the kinematic sequence is the order of peak speeds between segments. When it comes to the pelvis and trunk, which are the highest storage units of elastic and kinetic energy, we often think of an ideal sequence between these segments as having the pelvis hit its peak speed first followed by the torso hitting its peak speed second. We also want to see that the speed ratio between these segments to be 1.5x or more for the torso in relation to the pelvis.
In other words, if the pelvis is rotating at 600 degrees per second, the torso should rotate at least 900 degrees per second. If not, velocity may be less than optimal, and the arm may have to work harder to make up energy differences to increase arm speed.
The Art of Slowing Down
The main training emphasis among baseball players tends to be the speed of torso and pelvis rotation. While this is important, the ability to decelerate is the major determinant between elite and sub-elite pitchers.
In order to achieve the 1.5x or better speed ratio, the pelvis must decelerate well, and when it comes to the throwing arm, the torso must decelerate to transfer energy to the throwing arm.
Think of one segment pulling off the other. I liken this to synchronize skating. My sister was a synchronized skater and was positioned in the center of the formation. She was responsible for putting on the brakes to accelerate the outside skaters at a higher speed.
Consider the pelvis to initiate the chain of events that allows the trunk to be pulled at a higher speed when it can abruptly stop. When you look at the kinematic sequence below, you can identify the athlete’s ability to coordinate deceleration by looking at the line’s slope after peak speeds have been reached, which is signified by the dot. The downward slope can be measured, and training programs can be used to improve and cross-referenced for changes in the kinematic sequence.
In looking at the deceleration parts of the curve, you should see that the torso (blue line) has a much sharper descent. That allows a greater pull on the throwing arm to achieve higher peak speeds, and higher throwing arm peak speeds will most definitely increase throwing velocity.
Now, check out this ArmCare IQ, where we dive into evaluating the kinematic sequence and appreciate the deceleration component that gives rise to greater energy transfer in the delivery.
Then start assessing and structuring your training to build on the kinetic chain by using the Arm Care App as a measurement tool. By using the app after bullpens and games, you will determine arm fatigue for that outing. As the kinematic sequence improves, we should see less strength loss in the throwing arm. If fatigue is higher than 10%, meaning more than 10% strength lost from your fresh test, you may want to investigate your training, workload demands, and mechanics.