For the second year in a row I was able to attend the Saberseminar at Boston University. Here is a summary of of the conference, grouped loosely by category:
There were several presentations discussing pitcher health. First, the technology for pitch and biomechanical tracking continues to march forward. Between cameras and sensors, there are some pretty good, lightweight and fairly inexpensive methods for calculating and monitoring arm stresses. It is rather impressive. Armed with this new data, researchers are starting to draw some conclusions:
- Arm stress is correlated (obviously) with velocity, but only on a per-pitcher basis. So a 95mph pitch does not cause the same amount of stress for every single pitcher. Instead, there are two independent factors for each pitcher.
- First, it depends on the velocity range for the pitcher. A pitcher that usually sits 91-92 is (often) going to experience a larger arm stress increase from a 95mph pitch than a pitcher that usually sits 93-94.
- Second, every pitcher’s stress slope is different. So two pitchers who both sit 91-92 will both experience more arm stress when unleashing a 95mph pitch, but the magnitude of the increase may be different.
- “Throws matter, not pitches; recovery matters, not rest.” All throws (warmup, long toss, pitches) cause stress on the arm. Not all equally, but they all need to be accounted for. Similarly, the body’s recovery depends not just on time but a myriad of other factors including sleep, nutrition, therapy, etc.
Tracking all of this, and creating individual throwing and recovery plans, seems to be the frontier that is rapidly being explored.
There was a pretty damning study presented on weighted ball training. I might have the details slightly off, but from my notes and memory of the study:
- ~70 young HS pitchers were split into two group.
- Test group did an 8 week weighted ball throwing program
- Control group did the exact same program but with normal balls throughout
- After the program, the test group did have increased velocity (average 2.3 MPH increase), but:
- Test group had significantly more injuries, including a UCL sprain and a UCL tear.
- The overall shoulder/arm strength changes were the same for both groups
- The only physiological change was that the test group increased their layback - or how far their arm can bend backward.
The conclusion that was tentatively drawn here is that weighted ball programs don’t increase velocity via increased strength, but rather by stretching the shoulder/arm muscles/tendons to allow more layback, which in turn has potential negative health consequences.
There was a medical talk about Thoracic Outlet Syndrome. Lots of good info for a medical novice like myself. It is incredibly difficult to diagnose, because it has a multitude of symptoms (numbness, soreness in the fingers/arm/shoulder) that often only show up while pitching, not necessarily on the trainer’s table. And it has a multitude of potential sources (muscle, joint, tendon, artery) that may be compressing/inhibiting the nerves.
Moving to another topic area, there were several talks from former players and current executives. Many touched on the challenge of getting players to buy into analytics. Ben Cherington talked about how critical it is to have team leaders who can bridge that divide. From a Twins-specific perspective, one of the names he mentioned as a very good ambassador and teammate was Craig Breslow.
Another very good presentation was by Fernando Perez. He is an ex-player from the Tampa Bay system. He really challenged the conventional wisdom about the current player development process. A sampling of his observations included:
- Players are told throughout the low minors to “hunt fastballs”. Because of that philosophy and the middling quality of minor league stuff, he said that he could go days, even weeks, without ever swinging at a breaking ball except by accident. Then he gets to AAA and is told that he can’t get to the majors until he can hit a curve.
- A lot of hitting skill is developing muscle memory. Does hitting off a tee, BP, soft toss, etc help or hinder the formation of that memory? He has talked with people in other disciplines that involve forming muscle memory (including other sports and athletic activities like dance), and many of them are skeptical that the non-game work is that helpful.
- Most hitters want to be comfortable with their swings, and resist any changes or challenges during practice that will throw them off. But the entire job of a pitcher is to make a hitter uncomfortable! He talked about the need to develop improvisational hitting skills.
- A lot of coaching is figuring out how to get players to listen to and apply changes/suggestions. Some players are willing to try anything. Others need to be “tricked” into trying new things.
- For many (most) minor league players, affiliate assignments are made during spring training. And players are often told they can force promotions through their spring training performance. That, naturally, creates the incentive to come into spring training at peak condition. Is that best for the player/organization, particularly from a health perspective?
Moving onto the more sabermetric side…
Dr. Alan Nathan did another presentation discussing how baseball changes have contributed to the home run surge. By his estimation (and building on the work of several others), he calculated that the physical changes to the ball have increased home run rate by 15%, which explains most but not all of the recent home run surge.
Glenn Healey presented some work on measuring pitcher similarity. The basic idea is to use PitchFX data (pitch velocity and movement) to find pitchers who share similar “stuff”. Looking at a pitcher’s overall repertoire, he could improve next season strikeout projections by looking at pitchers with similar stuff rather than similar results.
Bill Petti looked at the factors that go into double-plays. His most interesting finding was that the likelihood of a double-play occurring is 80% dependent on the batter rather than the pitcher.
Brian Mills presented research that looked at the winners and losers from the changes to the strike zone in recent years. As has been shown over the past several seasons, the strike zone has extended down a couple inches. In response, pitchers are throwing lower than they did in past seasons. He looked at how batters fared on pitches in that lower zone, and how they have been helped/harmed by the increase in pitches to the bottom of the zone.
Julia Prusaczyk of MLBAM introduced a new metric for sacrifice flies. Using StatCast data, she created a model that will combine a fielder’s arm strength and a runner’s speed to define a cutoff line for trying to advance on a sacrifice fly. As a hypothetical example, she explored how Bartolo Colon the base-runner would fair against Bartolo Colon the outfielder.
There were a lot of other good presentations. Some were more on the fun side (ex. Under what conditions is it faster to bounce a throw to first); some were just high-level (ex. Using [machine learning technique, financial model, etc] to analyze baseball). This post is already getting pretty long, so I’m going to skip the rest. If you are interested, however, the list of presentations (with abstracts) can be found http://www.brooksbas...7/saturday.html and http://www.brooksbas...17/sunday.html. If you have any questions about a specific talk, I can answer questions in the comments.
Finally, there were at least two members of the Twins front office in attendance. I briefly chatted with both, and since I didn’t declare up front that I was going to share my conversation, I’ll keep this as general as possible.
One guy works at the Fort Myers complex. I was a recent hire, so I didn’t ask anything about the front office. But he did have a ton of great things to say (unsolicited) about Royce Lewis. According to him, Lewis is not only super fun to watch play everyday, but he is great with his teammates and everyone around the complex.
The other guy works in Minneapolis in the analytics group. I didn’t ask about the Jack Goin situation (I figured it was too soon). I did ask about the overall front office changes since Falvey’s hiring. From my perspective, his response was very, very positive. Also, he reiterated what has been publicly stated by Levine and others that they are looking to expand their analytics staff. He said they are swamped with work. Judging by how much time he spent working on his laptop during the presentations, that seems legit.