“” The Marriage of Rotation and Linear Translation: The Lower Half (Part One) - Driveline Baseball

The Marriage of Rotation and Linear Translation: The Lower Half (Part One)

| Pitching Mechanics
Reading Time: 8 minutes

It’s no stretch to say that hundreds of thousands of words have been written on the mechanics of the lower half as it applies to pitching and hitting, and most of them are inflammatory responses between various “camps” of theorists that believe they understand the perfect motion of the human body. The hitting camps include, but are by no means limited to: SETPRO’s Posture-Connection-Rotation (PCR, and later PCRwhip/PCRw), Teacherman’s Two Pivot Points, Dr. Chris Yeager’s Kinetic Link principles (primarily defined by lead arm extension and the four phases of hitting), Mike Epstein’s Rotational Hitting, Charley Lau’s Knob Pull, Jack Mankin’s Top Hand Torque… and many, many others. I won’t bother listing the pitching theorists out there, but a simple Google search for “pitching mechanics” will more than satisfy your curiosity.

The hitting camps used to be primarily divided by the Linear Style of Hitting and the Rotational Style of Hitting. These days almost all the camps agree that rotational hitting is the way to go; they all just generally disagree on the minutia of the mechanics.

Driveline Baseball isn’t a believer in any of the “camps” verbatim, though there is good information out there in many of them. Epstein’s tagline of “Do we teach what we really see?” is a good one, but one that should also be tempered by Paul Nyman’s “We are only capable of seeing what we want to see.” Dr. Yeager’s four phases of hitting (back leg load, back leg push, front leg block, front leg push) comprise the main stages of how we teach hitters, but we have found that the explanations of how to use the lower half cause a deficiency in rotational power. Teacherman’s theories on how the elbows should be spaced throughout the swing drive the arm action and upper half concepts of how we teach the optimal swing, but his theories on using the wrists/forearms to drive the bat don’t square up with the physics of the baseball swing.

That being said, I’m not here to give a review of everyone’s work and go into detail of how I arrived at how I currently teach hitters. I don’t think I have it all figured out, unlike the true believers out there. I do not have a God Complex (excellent TED talk); I am a firm believer in trial and error – and tons of empirical research – to arrive at continually better ways to teach athletes how to move properly to achieve the best results possible.

No, the focus of this article is going to be a long, boring, theoretical view on how the lower half marries the concepts of both the linear translation (push) and the rotational turn to produce the best bat speed possible while maintaining adjustability. The second article in this series will detail some drills that you can do to improve the lower half mechanics, and these concepts apply to both throwing a baseball and swinging a bat. The two movements are nearly identical when it comes to the concepts of how to drive rotational power, and this should not be forgotten.

Let’s start with both extremes – pure rotational turning power and pure linear translation.

Pure Rotational Turning Power

Proponents of pure rotational power believe that the stride is merely a timing device used to square up the baseball correctly in the swing. Phrases and cues often used by these coaches are:

  • “Forward by turning”
  • “Turn from the middle out”
  • “Rotate around the front hip”

Coaches who shun the linear components of hitting often instruct their players to begin the swing by turning the hips or coiling the front leg (internal rotation of the femur) and then aggressively rotating around the front leg to drive rotational power, and thusly bat speed.

Pure Linear Translation

Coaches who advocate a purely linear approach are quite rare these days, but still exist. They tend to focus on the following cues:

  • “Block the front leg”
  • “Must go back to go forward”
  • “The swing starts from the ground up”

Linear (lower half) hitting theorists lean heavily on ground reaction forces (GRFs) to make their case for the linear approach being the best approach for the baseball swing (and often the throw). By translating force up the front leg through a strong block against the ground, they seek to translate linear momentum into rotational power and generate bat speed.

Our View: Simplicity is Naive

Albert Pujols - Extension
This is NOT easy to teach. Sorry.

Both rotational and linear camps have their merits, but both try to simplify the baseball swing in order to sell a product or service and make their material easier to understand. The problem is that any complex movement involving human kinetics is rarely that simple to describe, teach, and model. You can point to someone’s swing and see anything you want, presuming you have the God Complex where your ideas are clearly the best and nothing else matters. This is evident in nearly all “gurus” who have something to sell, and with good reason – proclaiming that you’re an expert on a very complex subject is great marketing!

The truth is that understanding the an ideal model of the baseball swing is technically simple, but teaching it and performing it in a game situation is very, very hard. How could it be any other way? If it were simple, you would see these gurus having tons of clients in the upper echelons of baseball – and this is almost assuredly not the case. The vast majority of MLB hitters have never heard of these so-called “hitting experts” that have such vast domain knowledge of the baseball swing. And why is this?

Chaos Theory: Embracing Complexity and Randomness

Our view is that an efficient baseball swing that can be ported to a game situation for maximum effect (good bat speed, maximum adjustability) will have the following concepts:

  • A repeatable, simple timing mechanism
  • Efficient use of linear momentum into lead foot plant
  • Sudden and violent rotational contraction around the spine
  • Simple pathing of the upper body to deliver the bat’s barrel to the ball

The lower half in the swing must work both linearly and rotationally. This is of paramount importance, so I will repeat it:

The Ideal Lower Half Works Around the Spine AND Across It

A hitter’s lower body must have an efficient back-to-front push/block mechanism that gets the most out of ground reaction forces and provides a stable base to push/rotate against, but the lower body must also use the large muscles in the quadriceps area to drive pelvic rotation prior to shoulder rotation to achieve maximum separation between the upper and lower halves.

An excellent example of this separation is slugger Jim Thome, who is about to hit his 600th home run this season (Delmon Young’s reaction is quite good):

Jim Thome HR

Though this clip is truncated, you can clearly see how far his hips have turned prior to shoulder rotation. This is a “feeling” that is chaotic – to deny it would be foolish. Advocates who say you can control the bat to contact using the small muscles of the forearms and wrists have no understanding of kinesology – by the time the bat is launched at a spot, it is completely ballistic and cannot be “tweaked” to adjust. The bat launch angle and rotational plane must be set early on in the swing, and all of the power/efficiency is driven by the characteristics of the lower body. Period.

So, How Do We Embrace Chaos?

The chaotic nature of the separation of the lower/upper half cannot be controlled, but it can be embraced. There is an element of chaos and loss of control that one must simply accept when it comes to these types of motion; if extreme control of the distal parts of the body were possible with high bat speeds, then the best hitters who produce the most runs (guys who hit for power AND average) would barely strike out. Yet we see the best hitters strike out more than 100+ times per year. This concept cannot be ignored if you want to produce the best possible swing that you can generate. You must not only understand that there are limitations, but you actually have to learn to love the limitations! This game is random is many ways we cannot yet (and may never) understand, and this lends itself to some beauty.

In the next article in this series, we’ll talk about some of the concepts that marry the linear translation of the lower half with the rotational concepts of the middle to produce an efficient transfer up the spine and to the shoulders to generate high bat speeds with good adjustability. It does nothing to generate high bat speeds that cannot be effectively deployed in a game situation – at least in a real sport (go play men’s slow pitch softball if this is what you desire).

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