Popular Mechanics: Doug Thorburn helps break down the Oakland A's pitching staff

It was the summer of 2002 when I first stepped onto the field at Stanford's Sunken Diamond. A hot tip from an All-American teammate had brought me here at the tender age of 15 to work on my pitching mechanics. Surrounding me were other pitchers: younger ones, older ones, shorter ones and taller ones. Some us were prospects and, well, the rest of us? The rest of us were kids—mostly high schoolers—desperate to add a few extra ticks to our fastballs. The thought was that, if we improved our mechanics, that inevitable final growth spurt would push our fastballs out of the eighties and into the nineties.

I remember sitting on the grass, putting on my cleats, nervous. The previously audible whispers of my peers screeched to a halt as an average-looking guy with an unmistakable middle part and oval-shaped glasses faced us, his arms crossed. I saw him earlier waltzing around gingerly with his short-sleeved jacket, gesticulating at some other guy, who was also wearing a sleeveless jacket. It was Tom House. He didn't look like the storied pitching coach I had heard about: the guy who worked with Nolan Ryan, churned out USC pitching Adonises like Mark Prior and held the title as baseball's resident mad scientist of pitching. He seemed too normal for someone with a reputation for challenging conventional wisdom.

(You may have even heard about him in the news recently thanks to his work with NFL quarterbacks Tim Tebow and Tom Brady.)

Once the clinic started, we didn't touch a baseball for at least a half hour. Instead, all of us were given surgical tubing, typically an implement of geriatric care. We fixed it to the fence and learned a series of stretches unlike any I had seen before. We then went through a dynamic stretching routine, using our bodies and the structures around the baseball  diamond to create resistance. To stretch our shoulders, we put our hands together as in prayer, pushing firmly against one another before moving our elbows in a swimming motion. Then, the running drills: we would sprint and skip and karaoke across the field, constantly encouraged to be mindful of our heads relative to our centers of gravity.

The phrase "center of gravity" was used liberally.  It was the first time I had ever heard it used in a baseball context. In fact, most of the pitching clinics—or private lessons—I had attended were more dancing lesson than pitching lesson. It was like learning the Macarena or the hokie-pokie (put your right hand here, put your left hand here). Tom, in contrast, sounded like he was lecturing a college-level Kinesiology course, not a group of high school kids who mostly cared about sports. Still, it didn't lose its effect on us. He didn't treat us like we were dummies, and I—at least—appreciated it.

(Tom House, Then & Now)

Fast forward to 2012. I came across the work of Doug Thorburn. Plainly put, Doug is the Internet's preeminent authority on pitching mechanics. He draws experience from years of apprenticing with the aforementioned House. If you've ever read his articles or listened to him on a podcast, you know the level of detail and understanding he brings to the table—it's immense, and I highly recommend it. I made his acquaintance at a Baseball Prospectus event last summer and, more recently, asked him to help me with a series about the A's pitching staff in 2015.

Over the next several weeks, Doug and I will be discussing the A's staff from a mechanical standpoint. Pitching mechanics are important because they allow us look beyond the box score and identify strengths and weaknesses that provide a more nuanced view of the adjustments pitchers make, why they make them and whether or not they're working. Sonny Gray, for instance, invokes spine-tilt—which we'll talk about later—in order to get the vicious 12-to-6 break on his curveball, one of the best in baseball by any measure. Spine tilt isn't usually a good thing, yet Sonny, relatively slight in stature, uses it to raise his release point and create deception.

You may be thinking: if player X is in the major leagues, doesn't he, by extension, have good mechanics? The answer is a resounding no. The truth is, pitchers learn how to throw in all sorts of different ways.  Some are more effective than others. Teams and evaluators often take the if it ain't broke don't fix it line of thought, and a lot of a player's throwing ability is innate. Look at someone like Drew Pomeranz, who has below average torque—or shoulder-hip separation—yet due to his incredible arm strength can consistently get the ball into the nineties. That's more a function of genetics than mechanics.

Before we dive in, you'll need a brief introduction to the nomenclature of pitching mechanics—at least the version we will be using. There are five categories every pitcher will be graded on: Balance, Posture, Momentum, Torque and Repetition. Balance and Posture comprise the "Stability" grades, typically associated with command and efficiency. Momentum and Torque, as you can guess, make up the "POWER" grades—big power grades light up radar guns. Lastly, there's Repetition, the most important grade. If a pitcher can consistently repeat his timing pattern and delivery, it often makes up for a whole host of other issues. Vintage Cliff Lee, for example, had awful Balance—and relatively poor mechanics overall—but he repeated his delivery well enough to pitch himself into perennial Cy Young contention.

Let's look at the scale we'll be using to grade the categories.

The 20-80 Scale: A Brief History

Many of you are surely familiar with the 20-80 scale; but, for those of you uninitiated, it's the scale scouts use to evaluate talent. It's a five-base scale, meaning it moves in increments of five. A 50-Grade represents major league average, and anything above or below it signifies above or below average. You won't find any 20-grade major leaguers, for obvious reasons, and, theoretically 80-grade major leaguers are just as rare. Think generational talents like Bonds, Ruth, Mays (... Trout?). It's supposed to be a bell-curve like distribution, although the perception of "average" is in the eyes of the beholder, the evaluator.

The system we use now is a variation of the system front office legend Branch Rickey devised as the GM of St. Louis Cardinals. In the wake of World War I, semi-pro teams were going bankrupt left and right, which allowed Rickey to swoop in and create baseball's first farm system. In order to acquire enough talent to fill the teams the organization purchased, he gave his "ivory hunters"—or scouts—a system of measurement—mostly consisting of pluses and zeroes—to grade a player's physical gifts relative to major league average.

Al Campanis, a scout who worked under Rickey, longed for more precision. Sometime in the late 1940's or early 1950's, he created a new system of tool measurement. It was a one-based scale that went from 60-80, where 70 signified a "passing" or "average" grade. For example, upon seeing a young Sandy Koufax at a workout at Ebbets Field, he sent Rickey a scouting report that put a "77" on his amateur fastball. I'm not sure how the scale morphed from 60-80, to 20-80, but my guess is it mimics a normal distribution, with three standard deviations on either side of the mean (50).

The 20-80 scale earns the rare distinction of mapping intuitive, subjective evaluations in mathematical terms. It's imprecise, but there is beauty in that imprecision. The idea that the scouting eye is much like a sixth sense, that years and years of watching baseball with a most discerning eye, confers the right to "hang" grades on players is one of the great heirlooms passed down by our baseball forefathers. This is the scale we'll be using for evaluations, grading each of the aforementioned components of a delivery, resulting in an overall A-F grade. (For those interested in the subjectivity of Doug's evaluations, he recently audited his own grading system. Warning: paywall)

Next up, the Kinetic chain.

The Kinetic Chain

* Note: In this section, I’m paraphrasing Doug, with his permission, of course.

The Kinetic Chain is kinesiology speak for a series of movements associated with a physical action. The pitching motion, specifically, requires the coordination of both linear and rotational movements, and, like any chain reaction, a disruption at one point inevitably affects another further down the pike. There are several links, or checkpoints, on this specific chain, but, for simplicity’s sake, we’ll only discuss four of the major stops: set up, max leg lift, foot-strike and release point.

The set up is where a pitcher sets his hands before initiating his movement towards the plate. This is the beginning of what Doug calls the "lift phase," which culminates in the next stop on the chain, max leg lift. Just as it sounds, max leg lift is the point where a pitcher’s leg kick reaches its highest point, signaling the beginning of the "stride phase," when a pitcher continues his movement towards home plate. The stride phase ends at foot strike, or the moment a pitcher’s front foot, or landing foot, first comes into contact with the ground. After foot strike, the pitcher initiates the "rotational phase," a phase of hi-speed trunk and shoulder rotation that results in the releasing of the pitch, the release point.

(Check out this graphic of the Mariner’s Taijuan Walker for further elucidation.)

An efficient movement requires a very specific sequencing and timing of these events. The rotational phase, for example, is easy to biff up because it requires, within milliseconds, the coordination of complex linear and rotational movements. Freeze framing a pitcher at a given point and checking for, say, balance—told by their head position relative to their center of mass—can help us begin to explain the outcomes of specific pitches. It’s important to remember that the pitching movement is a continuous one and that a mishap at one point will surely manifest itself at another.

Next week, we’ll dig into the core components of Doug's Mechanical Report Card: balance, posture, momentum and torque.

*Doug is a staff writer at Baseball Prospectus. You can find him on twitter @Doug_Thorburn