How guys rotate is the most complicated, but most important part of the puzzle. To ease some of this complexity, I’m going to break this phase into two interdependent buckets:

1. What’s the body doing? 
2. What’s the barrel doing?

Starting with the body, below are some things I would consider when evaluating how a hitter rotates:

• How far does the body rotate? Is there a lot of pelvic/chest rotation, or does the swing require less? Does the chest close gaps of separation with the hips into contact? 
• Is there more of an external rotation bias or internal rotation bias? Hip flexion or hip extension? 
• Does the hitter utilize a kick back move? If so, when?
• Do they start with more forward trunk flexion, or less? Do they create a lot of side bend, or less? 
• Are the hips able to decelerate post contact? 
• Is there any sort of shifting, spinning, or wobbling/caving at the front leg?  
• Do they maintain space between their feet while rotating? Does the back foot find the ground again post contact, or does it get dragged forward into hip flexion?
• Does the head and spine stabilize and maintain alignment while the chest rotates? 

There’s a lot of detail in this part, but I would simplify it to this: It’s either good rotation, or bad rotation. To me, “good” represents an alignment between strategy and capacity. If how the athlete is choosing to move reflects how their body should physically move, it works. If something doesn’t move the way that it should – whether it’s a poor strategy or lacking capacity – it needs to be addressed. Sometimes you have to create better front side mechanics. Other times you need to put the front leg into a spot where it can work the way it should.

To figure out whether alignment exists, I like to see where guys exist on a few different spectrums:

• Degrees of overall rotation
• Internal vs. external rotation bias 
• Hip flexion vs. extension bias  
• Amount of trunk flexion and side bend 

Having a pulse for where guys are at on these spectrums adds some color to the picture. Everybody has specific strategies they tap into when they want to rotate fast. Some of these strategies are more innate – retroverted hip sockets favor external rotation. Others are learned – finding tension in the toes after years of practicing with a quad dominant back leg. I think the important piece here is finding what’s likely not going to change with coaching. Some strategies they’ve picked up over the years might need rewiring. But plenty others exist to give you a structure to work within. 

From a software standpoint, good rotation can look very different based on how guys present. So what does “bad” rotation look like?

I’d start with the following three things:

• Are the hips able to rotate cleanly into contact without any barriers to action?

Hip rotation is the foundation for rotation of the body. Where the hips go, the chest will follow. Any sort of shifting (body leaks forward), vaulting (hips extend early), or an insufficient amount of rotation (premature deceleration) will impact the delivery of the barrel. Underdelivered hips create underdelivered barrels. 

• Are the hips able to decelerate post contact?

How the body decelerates plays a big role in the transfer of energy up the chain. Just the way you’d crack a whip, the hips have to create a stopping moment to accelerate the upper body through. If you watch how the hips rotate into contact in slow motion, you should see the belt buckle freeze in space for a moment after contact. This is the hand cracking the whip. If this never happens, the front hip will spin and continue to rotate to the pull side. This negatively impacts both direction and force transmission.  

• Do the head and spine stabilize and maintain alignment during trunk rotation?

Most of the discussion to this point has been around the hips, but how the trunk moves has a big influence on the barrel. The spine works as the axis of rotation for the body. The hips and chest have to unwind around the spine to create space for the barrel to work. Any sort of shifting forward, leaning, or loss of posture (trunk loses flexion while rotating) changes the body’s axis of rotation. When the center point for the body moves, how the barrel moves around the body ultimately changes – making it a lot harder to get the barrel square consistently. It’s tough to ask the barrel to get to the same end point when it has to change its course mid flight. 

…

Moving to the barrel, below are some things I would consider when evaluating bat path:

• Does the barrel get delivered consistently? When it does, what does ball flight look like?
• What’s the general shape of the path? Flatter? More vertical? 
• Do the hands push, or does the barrel turn and create depth behind the ball? 
• Does the barrel turn with the torso? Or does it drag behind during trunk rotation?
• Where is the overall point of contact? Is the barrel traveling up or down into contact? 
• Does the back hand work with the back elbow? 
• Does the lead shoulder work up as the back shoulder works down? 
• What kind of length is created post contact? Is the bat out of the zone early, or does it stay through the zone?
• Is it more of a two plane swing with a vertical to horizontal entry (e.g. barrel tip), or does the bat work on more of a horizontal plane with the torso (e.g. flatter barrel set up/entry)? 

Of all the things you can evaluate here, the first question is ultimately the most important question: Does the barrel get delivered consistently? 

“Delivered” is synonymous with any of the following – closed, flush, square. For the purpose of the explanation, I’m going to use the term “square.” When delivering a strike – baseball, golf, tennis, etc. – the part of the implement you’re using to strike the ball needs to get square to its intended target. If your goal as a hitter is to hit the ball to center field, the bat head needs to face center field at contact. If the barrel is angled towards right field in this situation, it would be considered late, open, or not delivered. This could create a swing and miss, foul ball, or clip/slice.  

Using the same situation, let’s say the hitter got the barrel square to center field at contact. The initial trajectory of the ball heads towards center field. But as the ball ascends, it changes trajectory and starts to slice towards right field. This isn’t an issue with getting the barrel delivered. It’s a path problem: How the bat is moving negatively impacts ball flight off the bat.

These two observations create a simple, but effective framework when navigating path issues. If the direction is off, the barrel needs to get square. If the flight and trajectory are off, the barrel needs to move differently. 

If the barrel isn’t getting square, below are some potential reasons why:

• Poor hip rotation

The hips play an integral role in producing contact to different parts of the field. If you want to pull the ball, you need a point of contact a little further out in front. This requires more hip rotation. If you want to work to the opposite field, the point of contact shifts further back towards the catcher. This requires less hip rotation. If the hips stop rotating prior to contact, the body ends up decelerating at a critical moment in the swing when it should still be accelerating. The barrel isn’t to blame in this case. The body left it out to dry. 

• Bad swing thought 

It’s one thing to think about staying inside the ball. It’s another when the thought of staying inside the ball causes the barrel to never get delivered. You can do whatever you want to change the swing from a drill standpoint. If the swing thought never gets reframed into something more productive, the same issues will continue to show up. You have to change the thought process behind the movement first. The same bad blueprint will create the same bad movements. You can only begin to introduce a better movement if you take the time on the front end to build a better blueprint.  

• Too much counter rotation 

The further your body turns prior to the swing, the more work your barrel has to do to get back to center. Instead of starting at the start line, the barrel ends up starting twenty yards behind the pack. Can it overcome the bad starting position? Potentially. But it’s a lot easier if you just eliminated the clutter on the back end and had the barrel work from a better position to start. Everyone is going to create some sort of movement in the transverse plane during the load. The barrel will tell you when it’s become too much. 

• Shifting 

When the body rotates, the front side has to stop, stabilize, and prevent the body from shifting forward. This stopping moment helps decelerate the hips and slingshot the upper body/barrel through. If the body never stops shifting forward, the barrel can’t get across the body. It gets caught dragging behind because the axis it needs to rotate around keeps shifting forward. It looks like the barrel is late, but it’s not the barrel’s fault. The body never gives it a chance. 

• Dragging 

When the body starts to rotate, the barrel has to be ready to go. The two turn in tandem. There are points in the swing where one thing needs to move before the other (hip to shoulder separation). This is one of those moments where you can’t afford a delay in the action. Rotation of the chest should initiate rotation of the barrel. If it doesn’t, the barrel ends up wasting precious time dragging behind the body.  

If the barrel is getting square but the ball isn’t doing what you want it to, below are some questions I would ask to address overall path:

• What pitch locations/parts of the field are easiest to utilize? Most difficult?
• Does the barrel push and do the hands take over, or does it turn and unwind around the shoulders?
• Is there a positive ascension into contact? Does the barrel remain on a positive ascension post contact? 
• Does the barrel work inside to out, or outside to in? Where is the majority of the length in the swing created?

The first question is designed to gather context. It’s not a path problem until there’s something you need to do that you don’t have the ability to. The next three questions address the overall shape of the path.

Below are three different buckets you can group a large majority of those problems into:

• Push: Any movement where the hands push and get ahead of the body instead of rotating with the torso. Some of it can be thought influenced (e.g. take your hands straight to the ball). Other times it’s tied to someone’s identity as a hitter (e.g. the put the ball in play/contact guy who doesn’t miss). Misses are going to be on ground or high spin pop ups. 
• Dump: Excessive barrel depth behind the torso during trunk rotation. Misses will be under/late. 
• Cast: When the hands push away from the body during rotation of the chest. These guys will be your out-to-in paths. They’ll hit a lot of stuff to the pull side, but struggle to stay inside something and keep it off the ground.

…

At this point, you have enough information on the bat and body to start to pinpoint the roots of these problems. It’s never eight different problems. It’s usually two to three that create a variety of problems downstream. The hitter who sways might have an issue crashing into the plate, but telling them to stride straight won’t address the root of that problem. They need a better back leg loading pattern.

While much of the evaluation process to this point has been spent working middle out, figuring out where to start begins at the end. If you can reverse engineer from contact, you start with the best – and most consistent – feedback that exists: What is the ball doing off the bat? Everything that happens before contact might look like a train wreck. But if the ball comes off the bat at an angle, velocity, and direction with a high probability for success, it’s not just a good swing. It’s a great swing. It doesn’t need to look good. It only has to work good.

From a ball flight standpoint, I’d want to see if a hitter can check the three following boxes:

• Can you hit a low line drive to center field?
• Can you work to the opposite gap with power?
• Can you pull something in the air and stay behind it? 

The low flight/fly ball objectives give you a feel for vertical adjustability. The pull side to oppo gap approach challenges horizontal adjustability. The focus on driving the ball keeps intent coupled into the move. It’s one thing to hit a ball to the opposite field. Trying to drive the ball into the opposite field gap creates a completely different swing. 

It’s not to say you have to do all three really well – everyone has specific biases. But at the very least, in a controlled setting, I’d expect a good hitter to do these three things on cue. The game is doing to demand it at some point. If you need better feedback, you can always add layers to make the challenges a little more demanding (e.g. high spin fastball machine top third for low flight focus). 

When a problem with ball flight becomes noticeable, start to peel back layers. Is the barrel late, or is it moving poorly? If it’s moving poorly, where does it start? Is the issue more so with how they rotate, or is it where they’re rotating from? If the lower half a bigger culprit, or do the leaks mostly happen with the upper half/arms? The problems have been identified by this point. The most important part now is finding the roots of those problems. They tell you where to start.

Because that’s the challenge – you can start in a lot of places. But not a lot of places give you the best return for your work. Good coaches don’t play whack-a-mole. They play the game of leverage: Find what’s most important, attack it relentlessly, let all of the little details fall into place. And that’s where the fun starts. Because how you attack what’s most important is totally up to you – and that is the most beautiful part of coaching. How they choose to rotate is up to them.

But making sure they do rotate is up to you.