**Barrel Course**

At its core, hitting is a matter of hitting the ball arduous at productive launch angles. In a physics-sense, meaning creating an environment friendly collision between the bat and the ball.

The path by which the bat and ball are touring as they collide performs a job in how power is transferred between the 2 objects and in what path the ball is hit. It’s best for instance why the path of two objects issues in a collision by looking at a couple of easy examples (these visuals are from College of Colorado’s Collision Lab simulator, which you’ll be able to take a look at to get a greater sense of among the physics ideas at play throughout collisions):

Objects shifting on the identical path:

Objects shifting on the identical path:

Determine 1. Small modifications within the path of two colliding objects can have massive influences on the ultimate velocities and instructions of the objects.

These examples aren’t meant to exactly mannequin what’s going on in the course of the bat and ball collision, however they do present that small modifications within the path of the rate vectors of objects can considerably affect the resultant velocities and instructions of the objects after they collide. These are two-dimensional examples so there are solely two parts to the velocities of the objects (x and y). Within the above examples the objects begin with the identical preliminary x and y velocities, however you’ll be able to see that by making small modifications to how they collide the ensuing velocities are very completely different.

We are able to use this concept to consider the path the barrel and ball are touring in as they collide in the course of the swing, which supplies us a great understanding of why a sure swing might result in a given batted-ball final result.

Within the following evaluation we have a look at 4 completely different discrete variables that give a great image of the path and place of the barrel when contact occurs: vertical assault angle, horizontal assault angle, vertical bat angle, and horizontal bat angle. These 4 variables give an outline of what the place of the bat is and in what path it’s shifting at contact, which is able to assist us higher perceive why completely different swing traits result in completely different batted-ball outcomes.

*Vertical Assault Angle*

*Vertical Assault Angle*

Vertical assault angle (VAA) is a metric that most individuals studying this are in all probability accustomed to and one we discuss so much when coaching athletes. VAA describes the angle between the resultant velocity vector of the candy spot of the bat and the bottom (determine 2). Zero levels happens when the barrel is touring parallel to the bottom. A optimistic assault angle happens when the barrel is shifting upward and a damaging angle happens when the barrel is shifting towards the bottom.

Beneath we are able to see how VAA pertains to varied batted-ball outcomes:

*The optimistic relationship between VAA and exit velocity/bat pace is because of the truth that VAA will increase because the POC will increase, and each bat pace and exit velocity additionally improve with POC. The identical is true for the damaging relationship between VAA and spray angle. Unsurprisingly, launch angle will increase with a rise in VAA***.**

We don’t see any relationship between smash issue and VAA right here. That is probably as a result of we solely use the 8 greatest swings of a hitter’s movement seize evaluation, so smash issue will probably be comparatively larger for all swings which can make it troublesome to see bigger tendencies. It’s potential that this relationship is slightly completely different when bearing in mind a bigger pattern of swings, together with mishits.

However how does the next/decrease than anticipated VAA have an effect on batted-ball outcomes? We’ll first want to check out how VAA pertains to each POC and pitch top to create an anticipated VAA mannequin (determine 4).

We see that VAA relies on each POC and pitch top. This intuitively makes numerous sense.

*For a typical bat path, VAA goes to climb the additional out in entrance contact is made. Equally, it’s arduous to “chop down” or have a steep downward VAA when swinging at pitches on the high of the zone in comparison with swings on the backside of the zone.*

Utilizing these two relationships we are able to create a mannequin of what we’d anticipate VAA to be given a sure POC and pitch top. And from this mannequin we discover that the mixture of POC and pitch top explains 61% of the variance in VAA. Taking this a step additional, we are able to use this mannequin to see how hitters who fall above and under their anticipated worth primarily based on this mannequin carry out. In different phrases, we are able to see how having a VAA above what we’d anticipate at a given POC and pitch top impacts batted-ball outcomes (determine 5).

Determine 6. Instance of a hitter with the next than anticipated VAA (white) and a hitter with a decrease than anticipated VAA (pink).

Unsurprisingly, the one variable that appears to have any relationship to larger/decrease than anticipated VAA is launch angle. *Hitters which have the next than anticipated VAA primarily based on POC and pitch top are likely to hit the ball at barely larger launch angles than these with decrease than anticipated VAA.*

**Horizontal Assault Angle**

Right here’s the place issues begin to get actually fascinating. Not like VAA, horizontal assault angle (HAA) is one thing that’s talked about much less and fewer individuals are in all probability accustomed to what that is. HAA describes the angle between the resultant velocity vector of the candy spot of the bat and an imaginary line between house and the mound (determine 7). Zero levels happens when the barrel is shifting instantly towards the mound. A optimistic assault angle happens when the barrel is shifting towards the pull-side and a damaging assault angle happens when the barrel is shifting towards the other subject.

One of many motivations behind HAA was to aim to quantify how a lot a hitter “stays by” the ball. The thought being {that a} swing with the next than anticipated HAA is one which tends to result in slicing the ball as a substitute of “staying by”. Moreover, measuring HAA might enable us to quantify what coaches typically discuss with as out-to-in or in-to-out bat paths.

Beneath we see how HAA pertains to the identical batted-ball outcomes (determine 8). Just like VAA, ** the optimistic relationship between HAA and exit velocity/bat pace and the damaging relationship between HAA and spray angle are as a consequence of the truth that HAA will increase with POC**. That is probably additionally the case for why we see a optimistic relationship with HAA and launch angle. HAA and VAA improve as POC will increase resulting in larger launch angles. And like with VAA, we don’t see a relationship between HAA and smash issue.

Determine 9 helps to higher perceive why among the relationships between HAA and batted-ball outcomes proven above exist. We are able to clearly see that HAA is essentially depending on the place contact is made relative to the physique.

You’ll additionally discover that HAA modifications with the angle of the bat, which we’ll discuss later and is known as the horizontal bat angle or HBA. The extra the bat is angled in order that the barrel is pointing towards the pitcher, the bigger the HAA and vice versa. And we are able to see under (determine 10) that each POC and HBA have very sturdy relationships to HAA:

The rationale for these comparable relationships to HAA turns into apparent once we have a look at how POC pertains to HBA (determine 11):

Earlier than creating an anticipated HAA mannequin, it’s essential to keep in mind the placement of the pitch as we’d have motive to consider this might affect HAA. We see that horizontal pitch distance does certainly have a relationship to HAA (determine 12).

HBA occurs to be a barely higher predictor of HAA (R^{2} = 0.87) in comparison with POC (R^{2} = 0.82), so HBA was used to create an anticipated HAA mannequin. Utilizing HBA and horizontal pitch distance we’re capable of create a mannequin that explains 88% of the variance in HAA, and with this mannequin we are able to establish swings which have the next or decrease HAA than we’d anticipate.

When how HAA above expectation impacts batted-ball outcomes, here’s what we see:

Determine 14. Instance of a hitter with the next than anticipated HAA (pink) and a hitter with a decrease than anticipated HAA (white).

Increased than anticipated HAA seems to be related to decrease exit velocity, bat pace, and launch angle, however there is likely to be extra at play right here. With out context, it doesn’t make a ton of sense why launch angle could be affected by the next than anticipated HAA. When digging slightly deeper it turns into clear that this relationship is probably going as a consequence of the truth that a decrease than anticipated HAA is related to the next VAA (determine 15).

We are able to use a case research to higher exhibit why this relationship exists. Taking a look at separate swings from two completely different skilled hitters helps us to start to grasp why this can be. These two hitters took very completely different approaches to hitting practically an identical pitches:

When wanting from an overhead view we are able to see the completely different bat paths of Athlete A (pink skeleton) and Athlete B (white skeleton). From this angle it seems to be like Athlete A takes extra of an out-to-in path to the ball whereas Athlete B makes use of a extra in-to-out path.

That is considerably of an phantasm created by this attitude. When wanting on the behind (determine 17) and aspect (determine 18) views we are able to see that Athlete A’s and Athlete B’s paths are a bit extra comparable than they initially regarded within the overhead view. The paths have very comparable arcs however seem to happen on completely different planes. The truth is, it seems to be like a few of this might probably be attributed to the distinction in torso place between the 2 hitters.

Determine 17. Behind view exhibiting bat path of swings from Athlete A (pink) and Athlete B (white). | Determine 18. Facet view exhibiting bat path of swings from Athlete A (pink) and Athlete B (white). |

Another excuse these swings are perfect for comparability is that Athlete A and Athlete B had a really comparable POC and HBA however a unique HAA. Wanting on the desk under we are able to see that Athlete A has the next HAA, that means his barrel is working towards his pull-side greater than Athlete B. Certainly, Athlete A’s HAA is 3.4° larger than we’d anticipate given his HBA, in comparison with Athlete B who’s HAA is 6.1° lower than we’d anticipate given his HBA.

Nonetheless, these swings did lead to comparable outcomes:

We see that Athlete B achieved this decrease HAA by having a decrease VBA (that means his barrel is pointing extra towards the bottom) and the next VAA (desk 2). This pattern is supported by the connection we see in determine 15 exhibiting the connection between HAA above expectation and VAA.

*Swings with a decrease than anticipated HAA are likely to result in the next VAA because the barrel works upward reasonably than across the physique, whereas swings with the next than anticipated HAA are typically flatter and on a airplane that’s nearer to parallel to the bottom.*

Moreover, the distinction in posture between athletes on this instance seems to be emblematic of hitters that get flagged on both finish of the spectrum of anticipated HAA ⸺ ** a extra upright posture at contact seems to be related to larger than anticipated HAA and vice versa.** The damaging correlation between HAA above expectation and VAA additionally appears to elucidate why we see an identical damaging correlation between HAA above expectation and launch angle (fourth plot in determine 13). In different phrases,

*hitters that swing with the next than anticipated HAA are likely to have decrease assault angles and, due to that, hit the ball at decrease launch angles.*You additionally in all probability observed the damaging relationship between HAA above expectation and exit velocity (first plot in determine 13), that means {that a} larger than anticipated HAA is related to decrease exit velocities. It’s potential that swings with larger than anticipated HAA lead to much less power switch from the bat to the ball as a result of the barrel is working within the improper path, however it’s additionally potential that less-skilled hitters with decrease bat pace are likely to swing with the next than anticipated HAA.

When bearing in mind the damaging relationship between HAA above expectation and bat pace (second plot in determine 13), the second speculation appears extra probably. And looking out on the distribution of HAA above expectation throughout completely different taking part in ranges (determine 19) ** we see a pattern that, on common, hitters at decrease ranges are likely to swing the bat with the next than anticipated HAA when in comparison with hitters at larger ranges** (the distinction in HAA above expectation between highschool hitters and each faculty {and professional} hitters is statistically important).

Given these variations between the taking part in ranges, we are able to take one other have a look at the connection between HAA above expectation and exit velocity/bat pace/smash issue, this time break up by taking part in degree to see what relationships maintain inside every taking part in degree group (determine 20):

** Throughout all completely different taking part in ranges, bat pace is negatively correlated to HAA above expectation** (second plot in determine 20). Curiously, this isn’t the case when exit velocity (first plot in determine 20).

*Amongst skilled hitters we don’t see a relationship between exit velocity and HAA above expectation regardless of there being one for each faculty and highschool hitters***.**And since skilled hitters which have the next than anticipated HAA don’t have decrease exit velocities regardless of swinging the bat slower, there’s a optimistic relationship between HAA above expectation and smash issue inside this group of hitters.

A few of this can be defined by taking one other have a look at the distribution of HAA above expectation between the completely different taking part in ranges (determine 19). You’ll discover that there are only a few skilled and faculty hitters which have a HAA above expectation over 5 levels. Evaluate that to highschool hitters which have a wider unfold of HAA above expectation and the next proportion of hitters that swing with a HAA over 5 levels of what we’d anticipate. ** This means {that a} very excessive HAA above expectation is a attribute of much less expert hitters**, and maybe there may be some pure choice at play once we have a look at larger degree hitters. We are able to see that the damaging correlation between HAA above expectation and each exit velocity and bat pace lessens as taking part in degree will increase.

**Vertical Bat Angle**

Vertical bat angle (VBA) describes the angle between the bat and an imaginary vertical line perpendicular to the bottom (determine 21). Zero levels happens when the bat is perpendicular to the bottom with the knob pointing towards the sky and ninety levels happens when the bat is parallel to the bottom. Notice that it is a barely completely different conference than Blast Movement’s VBA metric, however the two are nonetheless measuring the identical factor.

Beneath we see how VBA pertains to the identical batted-ball outcomes. VBA will increase (bat will get extra parallel to the bottom) as POC will increase, so we once more see comparable tendencies as each VAA and HAA with exit velocity, bat pace, and spray angle. ** There does appear to be a really small optimistic correlation between VBA and smash issue (r = 0.11)** and no relationship between VBA and launch angle which differs from each VAA and HAA.

As proven under (determine 23 and 24), ** VBA relies on each POC and pitch top**. That being mentioned, solely 37% of the variance in VBA is defined by each these variables. Identical to with the assault angle variables, we are able to nonetheless create an anticipated VBA mannequin primarily based on each POC and pitch top to see how larger/decrease than anticipated VBA impacts batted-ball outcomes.

We see under (determine 25) that swings with larger than anticipated VBA have a really small correlation to larger exit velocity (r = 0.1) and barely bigger damaging correlations to each spray angle (r = -0.18) and launch angle (r = -0.21). And we see no relationship between VBA above expectation and both bat pace or smash issue.

Determine 26. Instance of a hitter with the next than anticipated VBA (white) and a hitter with a decrease than anticipated VBA (pink).

The discovering that VBA above expectation is negatively correlated with each spray and launch angle could be very fascinating however is smart when occupied with why that is likely to be.

*A decrease than anticipated VBA (barrel tipped extra towards the bottom) is related to the next spray angle (ball hit towards the other subject) and the next launch angle. This means that swings that fall into this class are likely to result in chopping the underside half of the ball which in flip results in weaker hit fly balls that tail towards the other subject. In distinction, larger than anticipated VBA might result in hitting the highest half of the ball which leads to balls hit tougher at decrease launch angles to the pull aspect.*

**Horizontal Bat Angle**

Horizontal bat angle (HBA) is the angle between the bat and an imaginary horizontal line that’s perpendicular to the road between house and the mound (determine 27). Zero levels happens when the bat is pointing instantly towards the other batters field (when the bat is completely perpendicular to the road between house and the mound). The barrel pointing within the path of the pitcher ends in a optimistic angle, whereas a damaging angle happens when the barrel is pointing within the path of the catcher.

Like the opposite variables mentioned beforehand, the relationships proven under between HBA and batted-ball outcomes are a results of a robust relationship between HBA and POC. Essentially the most notable and least stunning relationship right here is between HBA and spray angle (r = -0.74). *A rise in HBA (barrel pointed extra towards the pitcher) results in balls being hit to the pull aspect.*

Within the part on HAA we noticed how intently associated POC and HBA are. Nonetheless, horizontal pitch distance additionally dictates HBA to a sure extent (second plot in determine 29). Pitches on the inside half require a barely bigger HBA to make contact and vice versa (determine 30).

Roughly 89% of the variance in HBA is defined by each these variables and we see some fascinating issues when HBA above expectations (determine 31):

Determine 32. Instance of a hitter with the next than anticipated HBA (white) and a hitter with a decrease than anticipated HBA (pink).

First, you’ll discover that there doesn’t appear to be a lot of a relationship between HBA above expectations and both exit velocity or bat pace, *BUT* there’s a slight damaging relationship with smash issue (r = -0.15). This implies swings with larger than anticipated HBA are likely to lead to barely worse contact high quality.

There’s a small damaging relationship between HBA above expectation and spray angle and a small optimistic relationship between HBA above expectation and launch angle, each of which observe instinct. *Hitters which have decrease than anticipated HBA might wrestle to tug the ball and hit the ball within the air, whereas hitters with larger than anticipated HBA have a tendency to tug the ball at larger launch angles.*

That was numerous data and there may be nonetheless rather more to look into in terms of barrel path and bat path however, for now, listed here are a pair key takeaways:

● **The vertical and horizontal assault angles inform us what path the barrel is shifting in, which supplies added context to a hitter’s batted ball profile.**

Particularly, the next/decrease than anticipated VAA might clarify a hitters launch angle profile regardless of the place contact is made, whereas the next/decrease than anticipated HAA could also be influencing a hitters exit velocity, launch angle, and smash issue.

● **The vertical and horizontal bat angles inform us the place of the barrel of the bat, which might additionally present extra context to a hitter’s batted ball profile.**

Increased/decrease than anticipated VBA might assist clarify why a hitter tends to chop balls or hit top-spin floor balls and better/decrease than anticipated HBA might assist clarify why a hitter struggles to tug the ball and get the ball within the air or why they have a tendency to have a decrease smash issue.

Now that we’ve a greater understanding of how every of those variables relate to efficiency at a discrete time level within the swing (contact), will probably be fascinating to conduct full sign evaluation to see what is exclusive about your entire bat path of hitters at completely different talent ranges. So keep tuned for extra insights into hitting biomechanics as we proceed to dive deeper and deeper into the information!