The science of scouting: A biomechanical look at Gerrit Cole

The Pittsburgh Pirates spurned Rice third baseman Anthony Rendon to take the flame-throwing Gerrit Cole out of UCLA with the first pick in the 2011 major league draft. Cole’s arsenal features a fastball that sits from 94-96 mph (allegedly touching 102 mph once), a sharp slider at 88-90 mph and a hard change-up at 88-90 as well.

Scouting Gerrit Cole using a scientific approach

We’ll be using the same 2-D kinematic analysis method that we talked about in my article about Danny Hultzen’s mechanics. The video I’ll use is this series of clips shot by Texas Leaguers, available on YouTube:

This video is particularly good to use because Trip Somers (owner of Texas Leaguers and current major leagbue scout) has high-speed camera equipment that he used when shooting film of pitchers. His cameras are the same ones we use in the Driveline Baseball biomechanics lab, which have worked well for us. The side-facing view we’ll use isn’t perfectly lined up in the frontal plane, but it’s really close.

Metrics for analysis

These will be the same as the ones used in the Danny Hultzen analysis:

-Maximum knee height (absolute and relative to height)
-Degrees of shoulder abduction at foot contact
-Degrees of lead knee angle at foot contact
-Stride length at foot contact (absolute and relative to height)
-Degrees of maximum external rotation (MER)
-Degrees of lead hip flexion at ball release

Maximum knee height

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Cole’s maximum lead knee height is 48.01 inches, giving him a relative measure of 63.1 percent of his standing height of 76 inches (error unknown). Research indicates that the best pitchers have a maximum knee height between 60 and 70 percent of their standing height.

Stride foot contact metrics

  • Shoulder abduction (height of elbow) is about 120 degrees (error unknown). Research suggests elite pitchers are generally between 80-100 degrees at this phase of the delivery. This is a red flag.
  • Lead knee angle is about 159 degrees (error unknown). Research suggests elite pitchers are generally between 125-140 degrees at this phase of the delivery. This is a red flag.
  • Stride length is about 61.15 inches or 80.2 percent of his standing height. (error unknown). Research suggests elite pitchers generally stride 75-90 percent of their standing height.

image

Maximum external rotation

As I said in the previous article…

Maximum external rotation (MER) is actually a pretty big misnomer; it describes the angle at which the forearm “lays back” during the pitching delivery. This is due to a rapid turn of the shoulders as the inertial mass of the baseball pushes the hand and forearm back. The problem with the term is that “shoulder external rotation” describes the humerus rotating backward, while in reality scapular tilt is providing a significant amount of the “external rotation” during this phase.

It is, therefore, multiple components being measured as a single thing. Scapular tilt is hard to measure without markers on the scapula and a bridge connecting them, and so researchers have just grouped these variables together; it’s stuck ever since. Evidence suggests that scapular tilt varies between overhead throwing athletes, so comparing MER between athletes may introduce a gross error based on anatomical and congenital differences between the two.

Cole’s MER is about 198 degrees (error unknown). Research suggests that elite pitchers tend to range from 170-190 degrees of “MER” throughout the delivery.

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Hip flexion

At ball release, Cole’s lead hip flexion is about 107 degrees (error unknown). Research suggests that elite pitchers tend to be between 92-115 degrees of hip flexion at ball release.

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Wrapping it up

Based on research published by various sources, some of Cole’s kinematic measurements would be classified as “red flags,” namely the elevated position of the humerus and the extended knee at stride foot contact. These red flags are not guarantees or predictors of future injuries or decreased performance; they are only outliers when compared to a population of healthy professional pitchers.

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Comments

  1. Robby Bonfire said...

    Kyle – Any major league teams using this approach to improving pitcher mechanics?  And how does Stephen Strasburg rate on this scale?

  2. Kyle Boddy said...

    Jeff:

    If you can find me good video, I can. But a quick check reveals nothing decent. Ideally it will be 210 FPS or better, like Trip’s videos.

    Steve:

    Unlikely that he’s changed anything. Kinematics tend to stay stable for a person’s career unless they suffer a debilitating injury or consciously change their mechanics.

  3. Kyle Boddy said...

    Robby:

    I know some teams are doing something similar to this, yes. Not sure about Strasburg, I would need good quality video – which I don’t have.

    Jeff:

    Thanks!

  4. Jeffrey Gross said...

    Kyle,

    Can you break down the pirates 2010 pick, Jameson Taillon? I heard he had worrisome mechanics too. Seems odd to risk so much two years in a row on combustible power arms.

  5. Scott J. Tepper said...

    I think your “stride foot contact” measurement—of the actual contact point—is off. Gerrit is sliding the left foot at least 2 inches beyond where you indicate there is contact. I think that value needs to be re-examined and adjusted. If so, what does that do for your red flags?

    I’d really like to see an analysis of Gerrit’s teammate, Trevor Bauer.

  6. Kyle Boddy said...

    Scott:

    I determine SFC when the foot contacts the ground relatively solidly and before the shoulders have turned. I think my measurements are correct, but if we changed them to slightly later, I don’t think it would make a large difference (I actually think it would be less favorable to Cole with a quick eye-check).

    I would love to see an analysis of Bauer as well. However, there is insufficient video out there to do so. Trip Somers has video of Trevor, but not from an appropriate angle.

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