Front-Arm Dominance - Why These Hitters Are More Likely to Be Great

People think my approach to the baseball swing is crazy when they first hear it.  After all, I advocate just one drill - the front arm progression.  Typically, swing coaches have thirty to forty drills in their arsenal. 

I'm also different in more fundamental ways.  Ask any swing coach what his goal was in starting on his path, and he’ll likely say something like, “I love coaching” or “I’ve always wanted to own my own hitting facility.”  Coaching or owning my own facility was never important to me.  My goal has always been to figure out the baseball swing.  Everything else was secondary.  

I wanted to understand how it was that guys who never worked on their mechanics could hit the ball so well so consistently, while I was working my ass off and could hardly hit the ball out of the infield.  There had to be something going on in their mechanics.

The first thing I did was immerse myself in video.  Back when hardly anyone was using video to analyze swings, I was filming hitters every chance I had - pros and amateurs - looking for the key differentiators between the great hitters and everyone else.  After many years I started to understand what a great swing looked like.  But I still didn’t know what it felt like.  And feel, when teaching, is really all that matters.

For a long time I just couldn’t tell what the great hitters were feeling that set them apart. Then I stumbled upon one key fact: a majority of the greatest hitters of all time were left handed hitters who threw right handed.  

This has been known for a long time.  I’m not the first to write about it.  But I am the first to correlate it directly to the best swings of all time.  If you look at the top pound for pound hitters of all time, 33% of them batted lefty and threw or wrote with their right hand including some names at the very top - Babe Ruth, Lou Gehrig, Mel Ott, Ted Williams, Ken Griffey Jr., Jr., and Barry Bonds.  And this is a handedness trait that is seen in only 2% of the general population.  This isn’t just a quaint statistical oddity, but we could be scratching the surface of the most important understanding in the history of baseball swing instruction. 

You see, it’s not just lefties.  Of the more than 20,000 major league baseball players throughout history, there have been only seven, count ‘em seven, who batted righty and threw lefty*, and the average career OPS+ among these seven hitters was 108!  That’s better than Hall of Fame third baseman Brooks Robinson.  The only one who finished with an OPS+ below 100 was Johnny Cooney, who also split his time as a pitcher.  

So it’s not that lefty hitters who threw righty were more likely to be great; it’s that hitters who have a more coordinated and strong front arm are more likely to be great.  Whether that hitter is righty or lefty is insignificant.  

Actually, it has to do with when they were learning the swing.  When a child learns the swing with a coordinated and strong front arm, the structure of the swing is drastically altered from that point forward.  It’s as if he heads down a certain mechanical path.

It’s quite natural for the human body, when learning a new movement, to quickly begin to delegate most of the “burden” of the movement to one side of the body.  Take the basketball jump shot.  Kids always start off shooting with both arms equally contributing, but pretty soon one arm dominates the move and does an overwhelming majority of the pushing, and the other is assigned with supporting.

Similarly, when a child is first learning the baseball swing, one arm quickly takes over and begins to dominate the move, depending on the strength and coordination in each arm at the time he is learning it.  It’s less obvious than in the jump shot because we hold the bat with both hands, but still discernible if you know what to look for.

The hitter is utilizing more of the front side of his body in a front arm dominant swing - using his latissimus dorsi, teres major, infraspinatis, and deltoid, basically the entire front side of his torso - as he transitions from the stride into the forward swing.  In a back arm dominant swing, he uses more of the rear pectorals and triceps to push the bat through.  This leads to different positions of the body as he goes through the swing.  

In a front arm dominant swing, the front humerus gets more compressed at the start of the swing, as opposed to a back arm dominant swing where the hands work more in front of the chest.  Also, contact tends to be made more connected - the front arm closer to the body and the back arm more bent - in a front arm dominant swing.  Whereas in a back arm dominant swing contact is made more out in front, more disconnected.  You can see this in the picture below that compares Ken Griffey Jr., a front arm dominant hitter, with Tony Gwynn, a back arm dominant hitter.  Gwynn was the greatest back arm dominant hitter that ever lived, and still wasn't able to reach the career OPS+ of Griffey, who was far from the greatest front arm dominant hitter that ever lived.  

Both hitters were unbelievably good; the point is that to optimize your production as a hitter, it's much better to be front arm dominant.  But here’s the key to all of this: it doesn’t feel to a front arm dominant hitter like his front arm is dominating the move.  This is why great hitters aren’t writing groundbreaking books about the key feeling of the baseball swing.  To them, it feels like every muscle in the body is contributing equally.  The same way Steph Curry’s shooting hand isn’t more tired than his non shooting hand after a 40 point game.  His body is used to it; it has grooved that move.

In fact, your body literally grooves the movement, making it feel normal to you, even though it wouldn’t necessarily feel normal to others if they could step into your body.  When you learn a new movement, electrical signals are sent through circuits of nerve fibers.  The more you do the movement, the deeper these pathways get ingrained.  This triggers the development of myelin, which works almost like a glue keeping that ingrained movement in place, which makes the movement more reliable and automatic.  That way a hitter can focus on the pitch and still subconsciously perform the swing without having to think about it. 

It’s all about the brief period in time when you learn the swing.  A movement always has the “signature” of your body composition - your left or right arm dominance - when you were first learning the move.  It’s like you “head down a certain path” when you learn movements, and unless you at some point consciously restructure the way you feel that movement, you will always be “living” within that particular neural pathway.

In order for you to become a great hitter, therefore, you need to consciously change your swing to be more front arm dominant, or "body-controlled." You can teach an old dog new tricks.  And in this case the way to do it is with the front arm progression.  

(* = with 3,000 or more at-bats)