As most people here know, I’m building a DIY biomechanics lab in my training facility located in Seattle, WA. We finished our control object a few weeks ago and filmed the first few test subjects just last week. I’m happy to report that my biomechanics intern and I have digitized the first two pitchers in our lab, and I’d like to share with you some preliminary kinematic data from one of them.
(Sorry if the image is a bit large.)
This still from our kinematic software shows a pitcher (video redacted for privacy) and his 3d model as digitized in our software. To smooth data collection, we used Butterworth filters of varying cutoff frequencies depending on residual analysis; this may not be the best way to do this, as a standard cutoff frequency tends to be more prevalent in research literature.
The graph shows the resultant velocities for the pitching arm hip/shoulder/wrist. (The vertical black line marker is the approximate time of shoulder maximum external rotation - or MER. The motion digitized represents foot strike to ball release.) You can see the velocity curves move in tandem with each other as expected with the modern concept of the kinetic chain - force is transferred from proximal to distal, and from the largest to smallest body part. In this case, the hip rotates quickly first, then the shoulders, and then the wrist.
This is only the preliminary data and results from the software. We plan on measuring far more variables with a report that is similar to what you might see from ASMI. (See also: Biomechanical Analysis of Dr. Mike Marshall’s Pitching Technique
- PDF file)
Hope it was as exciting for you as it was for me! Three years in the making and we’re finally getting some real work done. Now, all we need are four more high-speed cameras and a lot better lighting…