One of the features of TINSTAAPP, the podcast I co-host with Paul Sporer, is what we call “homework,” in which we investigate topics from listener emails through a combination of statistical analysis and video scouting. We also assign homework to one another, and last week's assignment for Paul was of Advanced Placement quality: to study the different “gears” in a pitcher's momentum.

The difficulty factor for evaluating momentum is magnified by the poor viewing angles available on standard television feeds. The center-field camera (or worse, the off-center camera) provides a terrible vantage point for viewing momentum, though it does offer a strategic angle from which to see elements such as dynamic balance and posture at release point. Momentum is best evaluated from a side view, sitting down the first or third baseline, where one can isolate the directional forces that a pitcher puts into his motion.

This optical reality created an obstacle in Paul's homework, and after discussing the issue on the latest episode of TINSTAAPP, we decided to extend the assignment. I had admittedly thrown a gauntlet in Paul's direction, and his questions highlighted a few areas that clearly warranted a more detailed explanation. We can get a better sense of momentum by breaking it down into phases, while directing attention toward the pitcher's center of mass (approximated by the belt buckle) as he travels down the mound.

The key subject under discussion is what I refer to as a “gear shift,” in which a pitcher changes the speed of his momentum at some point in the delivery. Dozens of major league pitchers have a blatant change in their momentum, and the common technique is to invoke the gear-change at the point of maximum leg lift (when the lift knee reaches its apex), though there are other pitchers who get more creative. Let's take a look at some of the methods that big league pitchers employ when shifting gears.

The Stop at the Top
One coaching strategy is to have pitchers “stop at the top” in order to find a balance point in their delivery, a trend that is pervasive among pitchers in Japan. These pitchers might have a strong first gear with momentum directed straight toward the plate, but they suddenly halt their momentum once they hit maximum leg lift. In extreme cases, they will pause and wait before recruiting kinetic energy once again to charge into foot strike. The technique is inefficient from a mechanical standpoint, as any kinetic energy that is generated during the first gear goes to waste, and the secondary charge to the plate is driven from a stork-like position with the pitcher standing on one leg.

The other issue with the “stop at the top” technique boils down to timing, as the slow time pattern and abrupt change in momentum hamper pitch consistency. The problem is exacerbated by any necessary adjustments to a pitcher's timing from the stretch. Brushing the negatives aside for a second, the stop-at-the-top method does allow us to easily isolate the different gears of a pitcher's delivery, as the pause marks the point that these players shift from first gear into second. The Nats' Dan Haren is perhaps the most egregious example of what it looks like to stop at the top, as he transitions from an extremely slow delivery in the first phase to one that ramps up once he shifts into second gear.

The Twister
There are a number of players who have invoked a reverse twist into their lift patterns, rotating the body away from the target as they reach maximum lift. Felix Hernandez is perhaps the most famous twister, but other examples include Zack Greinke, Brandon Morrow, and Tim Lincecum. The twist can serve multiple purposes, and in the case of Hernandez, the strategy is used to keep him closed into foot strike, rather than opening up too early with either the hips or shoulders.

The twist is integrated into the first gear of a pitcher's delivery, from first movement to max lift, and there are pitchers who can parlay the twist into a second-gear advantage by uncoiling with increased fervor. Some pitchers with a twist will actually drift backward with their center of mass during the first phase of momentum before redirecting their energy toward the plate, but Hernandez employs the more efficient strategy of moving forward, toward the plate, while executing the coil.

The Tornado
If King Felix can be described as a twister, then Jonny Cueto must be the tornado of the first-gear coiling strategy. Cueto's reverse rotation spins him away from the plate such that he is essentially facing center field by the time he reaches the top of his delivery. The strategy pays minimal dividends despite the extreme nature of Cueto's twist move, due to his lack of forward momentum throughout the delivery.

Cueto has a first gear that gains little ground toward the plate, instead halting his forward progress into max leg lift, and he uncoils with modest intensity that fails to make up for the early disadvantage. The twist move often creates issues with coordinating the delivery from the stretch, particularly in the case of Cueto's tornado, because the pitcher lacks the time necessary to invoke the same degree of coil with runners on base and therefore must configure a much different timing pattern.

The Reverse-to-First shift
Generally speaking, the best pitchers initiate the delivery with a first gear that directs energy straight toward the target, but some players will drift backwards before the pendulum swings to the plate. Yu Darvish is arguably the top pitcher in the game right now, but he utilizes an inefficient pattern of momentum when pitching with the bases empty, shifting into reverse as he reaches the top of his delivery. Unlike Cueto, Darvish is able to produce solid momentum after he shifts into second gear, helping to extend his release point.

Much has been made of the mechanical adaptation that Darvish has made since last season, in which he has ditched the windup and instead pitches exclusively from the stretch, even without runners on. Despite this seemingly seamless transition, Darvish still alters his delivery when baserunners are in a position to steal, as he abandons the reverse gear in favor of a burst toward the plate that triggers directly from first movement.

The Down-shift
Occasionally, a pitcher will display a strong initial charge to the plate, only to slow things down from max lift into foot strike. The Brewers' Wily Peralta is just such a player. His first move is excellent, leading with the hip and initiating momentum straight toward the plate, but he looks as if he is pitching into a stiff wind during the secondary phase, slowing his charge into foot strike. The down-shift of momentum effectively mutes Peralta's stride length, and once again the issue of a slow delivery opens up the time-based opportunity for the delivery to fall off track.

The First-to-Third shift
Jordan Zimmermann has excellent momentum, earning a grade of 70 for his overall burst with plus marks throughout his charge. He has a strong first gear into max lift and continues to increase his momentum until he hits foot strike. Zimmermann displays a seamless transition out of max leg lift, with speed that can be described as a gradual acceleration rather than an abrupt gear change. His momentum then picks up speed just before the front foot comes into contact with the ground, as he finds a third gear that gives him an incredible charge into foot strike.

The Hyper-shift
Zimmermann's stride pattern might seem complicated at first glance, but nothing compares to the wayward momentum of Clayton Kershaw, who gets a bit trigger-happy with the clutch. Kershaw's first gear is fine, but he slips into neutral after max lift, essentially stopping his forward progress while the lift leg comes down from its apex. Then, just before the foot is about to hit ground for a potentially miniscule stride, the Dodger southpaw invokes a powerful burst toward the plate. He keeps his foot from making contact as he glides down the slope on the wings of his late thrust to the target, allowing him to make up for the deficiencies caused by his bizarre shift into neutral. The crazy momentum pattern is largely responsible for the left-hander's struggles with pitch command earlier in his career, but he has since mastered the sequence to the point of excellent repetition.

The Non-shift
On the flip side of Kershaw is Jeremy Hellickson, whose pattern of momentum appears to lack any type of shift. Hellickson has a steady pace throughout the delivery, with his center of mass traveling at virtually the same speed from first movement into foot strike. His first phase of momentum has decent forward movement, but he maintains a deliberate pace to the plate after maximum leg lift. Though I appreciate the fluid consistency of his motion, Hellickson has plenty of room for improvement with his sheer speed down the slope. His lack of acceleration produces a below-average aggregate score for momentum, effectively limiting both his stride length and the contribution of his lower half with respect to generating kinetic energy.

The Double-clutch
Owner of perhaps the craziest pattern of momentum in the big leagues, Hisashi Iwakuma takes the “stop at the top” paradigm to new levels. Combined with a bizarre samba prior to executing leg lift, Iwakuma's gear-shifting strategy can best be described as a double-clutch. He utilizes the mid-momentum pause, but just when it looks like he is going to re-initiate forward momentum with a slight lowering of the knee, the leg comes back up again before he actually triggers the next gear of his delivery.

Iwakuma finishes with strong momentum despite the double-clutch move, but his excessive halt in momentum acts as an obstacle to timing as well as an inhibitor of raw speed to the plate. He ditches the double-clutch from the stretch, instead triggering an amazing burst to the plate directly from first movement, with an awesome charge that leaves one wondering if he would be better served by leaving the windup at home when he leaves for the ballpark.

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Great stuff as usual Doug. I was wondering where you think two specific pitchers fit into all of this. I'm wondering about Justin Verlander and Cole Hamels. Verlander's everything seems smooth and he obviously gains serious momentum. Hamels seems to have a slight rock back in his windup, but ditched it with men on base to either have a straight up down balance at the top when holding a runner on first or just a straight explosive push towards the plate.

How do these two fit? Also, curious if lefties or righties exhibit specific patterns when shifting momentum.
They go over both those pitchers on the TINSTAAPP podcast, you should have a listen its very informative and they cover a whole lot of pitchers.
Thanks for the tip of the cap, Psych! I certainly encourage everyone to give TINSTAAPP a listen, but understand if the 3 hour 'cast takes awhile to sift through - luckily, we time-stamp each episode to make it easier to pick out the specifics.
Great question. To answer the last thing first, I have not noticed any specific tendencies with momentum based on handedness, aside from the trend for lefties to direct their momentum off-line on a closed pattern to create angle.

Regarding Hamels, it might appear as if he is rocking back as the leg comes up and he invokes a *slight* reverse twist, but his center-of-mass is actually drifting toward the plate during his first gear. Interestingly, his delivery did not feature a blatant gear change last season, but rather a continuous progression of acceleration. But his lateral movement is slower into max leg lift this year, with a distinct gear change after max lift. Combine that with balance that is weaker than last season, and you have a recipe for poor consistency into release point.

As for Verlander, you're right that he has a very smooth transition after max lift, and though he does shift gears from slow to fast, it is not as abrupt as many of the pitchers in this article. His momentum is excellent overall, despite a somewhat slow lateral move during leg lift.
Fantastic stuff, it really makes me wonder why you haven't been hired as a pitching coach already? haha it seems like most pitchers actually have better momentum from the stretch, how come they still use the wind-up? Are most pitching coaches stuck in their old ways and haven't evolved yet? I would think if that is their job they would be able to notice these things as well.. seeing as how mechanics are pretty essential to being successful on the mound.
Great call, Psych. Most pitchers do have better momentum from the stretch, and some players have better overall mechanics when they get out of the windup. The common issue is that pitchers spend less time working from the stretch (both in-game and warming up in the bullpen), and the timing disparity from windup to stretch contributes to inconsistencies.

I happen to agree that the windup works as a detriment to many pitchers, and today's version of the windup brings little to no functional advantage (in contrast with the windups of the past). This is a huge issue at the amateur levels, as young players struggle mightily to harness two distinct timing patterns for stretch and windup. I often say that Little League coaches teaching windups is equivalent to teaching calculus to a geometry student, yet they all do it anyway.

I wrote about this issue with windups a couple weeks ago in a piece called, "Time to Unwind" -