As I've done on a few occasions over the last year, I'm going to take a look at the mechanics of Astros Triple-A pitcher Nick Tropeano. A quick review of some of the fundamentals of pitching mechanics as well as examples of some of the verbiage used when looking at them (especially through kinematics) can be found here.
Video for this analysis was filmed by me in Nashville, TN against the Nashville Sounds in May of 2014.
Tropeano has a maximum knee height of 52 inches or 68.4% of his height. Elite pitchers are at 60-70% of their height. This has a relationships with timing and stride length.
Here is where NiTro gets into a lot of trouble. His stride is 59 inches long or 77.6% of his height. Elite pitchers stride 75-90% of their height. He's in the green here but is on the short end which does reduce his perceived velocity. His lead knee is at 138 degrees. Elite pitchers are in the 125-140 range. He's in the green but is also at the upper range. These are all tied to momentum. By having a relatively straight knee, he provides a block to his momentum toward the plate. He gets a little more flexion in his delivery, but very minimal.
As you can see, Trope has a very high shoulder abduction angle, around 140 degrees. Elite pitchers are in the 80-100 range. Well above where he needs to be. While his shoulder isn't internally rotated like the famous "Inverted W" pitchers. It is similar. Because his shoulder is neutrally rotated, he's in a "horizontal W" position with extra abduction. Or he's in the inverted W position with less internal rotation. Whatever you want to call it, that much shoulder abduction is not good. You are putting your shoulder at risk due to the rotator cuff tendons being brought close to the acromion process and setting yourself up for possible rotator cuff injuries. It also increases the distance the elbow has to travel to reach max external rotation and potentially increasing the force placed on the elbow. This is also a timing concern.
Max External Rotation
Tropeano has 170 degrees of external rotation whereas elite pitchers have 170-190 degrees. He's on the low end and this is tied to velocity. There are obviously several other factors included as well.
Tropeano has about 105 degrees of hip flexion at release. Elite pitchers have 92-115 degrees. He well in the range. This is a big one for the deceleration path the arm takes after release as it needs to be in this range to allow the trunk to flex and rotate to allow for a long enough pattern for the arm to slow down. Too long of a stride can inhibit this and also prevent knee extension to help with energy flowing up the chain. Tropeano doesn't have an issue here.
That shoulder abduction angle is a train wreck. He uses his arm for a lot of force production and that arm action he carries is a way to accomplish that. His momentum is produced through backing up in his delivery before leg lift but he can't do that from the stretch. That carries over into his stride and his early hip rotation is what allows for him to create his back extension and allow his shoulder to get to that position.
He can surprisingly repeat it fairly well, however, with all of the moving parts, that is not a guarantee to last forever. They already manifest at times when his velocity drops down to 89 for some pitches. His body segments do not properly line up at times resulting in his arm carrying a lot of the load.
The good side is that he leads with his hip quite well. The downside is that he doesn't get much out of due to his stride.