Pitching Arm Slot Velocity

By Ryan Faer

Figure 1 Correlation between Arm Stress and Ball Velocity, for top 9 velocity throws (n = 15 pitchers, 97 pitches) So, what about the other variables that the Motus sleeve spits out? I can’t tell you with 100% certainty what arm slot, or shoulder rotation means from these data, but I included ball speed, arm speed, arm slot, and shoulder. Both of these mechanical problems can cause a pitcher to have a lower arm slot than they otherwise would. They also lose a lot of velocity and command. Basically, with a good weight shift, good uphill shoulders as they stride, and good use of the front side, pitchers will have a more repeatable, slightly higher arm slot and better command.

9 Factors That Strongly Influence Pitching Velocity

In today’s baseball age, where a 90 mph fastball is now considered below average in Major League Baseball, the question inevitably comes up: how do I throw harder?

Recently I received a question along these same lines on Snapchat, where I field many baseball training questions each day. The question was a variation on the above: “How can I get stronger and throw harder?”

I did my best to answer this question as thoroughly as I could through social media – and in the process learned that there is in fact a limit to how much you can type in a single Snapchat message – and also posted it on Twitter. But, of course, this didn’t leave much room for elaboration. Thus, I wanted to take a few moments to expand upon the topic for everyone to take in. And, because I’d like to go into as much detail as I reasonably can, I have broken this article into three parts. All three segments, together, will touch on nine highly influential factors that affect velocity in baseball.

While the nine factors included in this 3-part series are all influential on velocity, they are not the only factors involved, as pitching velocity is an incredibly complex, multifactorial performance characteristic.

That being said, below I have included the first three of nine strong influencers on throwing velocity, strength, and everything in between:

  1. Strength

While this topic could certainly take up volumes and volumes of books, generally I am speaking to the ballplayer who has very limited training experience, if any at all. In this case, strength is actually relatively straight-forward.

  • First and foremost, learn to move well. We should not strive to put a ton of load on top of dysfunction. In other words, going heavy with poor movement is not going to build us a big strong house, it is going to build us a stick-house ready to be knocked down as soon as it meets strong opposing forces. As a beginner trainee, you will get stronger just by virtue of loading sound movement patterns, thanks to the Central Nervous System. Load does not have to be a barbell or dumbbell, it can come in the form of your own body weight as well.
  • Once movement quality and proficiency have been established, Progressive Overload must be sought in order to develop strength over longer periods of time. This essentially means that we must gradually increase the demand on the body in order to create the adaptations that we want. This, in turn, also involves the SAID principle – Specific Adaptations to Imposed Demands – which means that, if we want to create a specific adaptation (e.g. strength), we must expose the body to those demands. Thus, to get stronger we must gradually expose the body to greater loads.
  • The most efficient and effective way to load the body for strength is to utilize complex, multi-joint movements, such as squats, hip-hinges, pulls, and pushes. You don’t need to limit your training just to these movements, but there is certainly no strength-training program out there that doesn’t include exercises that fall into these movement categories.

A couple additional considerations on strength:

First, building strength can be thought of as developing a capacity for power (more on power below). Essentially, the more strength that we develop, the greater potential that we will have to produce power (i.e. throw harder). Without adequate strength we must find other ways bridge the gap and create that power.

But on the other hand, possessing strength does not necessarily guarantee velocity or power. There are still other factors involved. Put very crudely, if strength were all it took to throw a baseball 95 mph, we’d have more powerlifters in Major League Baseball, as they possess some of the greatest absolute strength numbers that you will find.

  1. Power

The equation for Power as it relates to baseball and strength training is P = Force x Velocity. This means that Power, at its base-level, is influenced by two variables; how much force (or strength) you can apply to an object, and how fast you can apply that force in a given direction. At its core, this means that strength alone can’t guarantee power. But, given the appropriate training for power, where both ends of the spectrum, and everything in between, are addressed, we can translate strength and speed into power.

Pitching Arm Slot Velocity

The spectrum mentioned above – the strength-speed (force-velocity) continuum – is another important concept to consider. Strength and Speed (or force and velocity) are inverse variables – meaning as one increases, the other decreases – or, as we increase the force required to move an object, the velocity has to decrease, and vice-versa. Some examples:

  • Take an athlete with a 400 lbs. max on the Squat. If the athlete were to put 200 lbs. on the barbell, they could squat it with much greater velocity than they could if they put 350 lbs. on the barbell.
  • A pitcher can throw a 4 oz underweight baseball with greater velocity than an overweight 7 oz baseball.

These variables are inverse because, to apply greater force (which is needed to overcome a heavy load) longer periods of time must be allowed for increased neurological connections to occur with the muscles being used.

Forgetting all of the science behind it, just know that strength alone can’t dictate throwing velocity. This is why there are many successful pitchers who do not possess great weight room strength, yet can hit absurd numbers on the radar gun. They have found other ways to make up for that lack of strength on the other side of the spectrum – by increasing velocity (i.e. arm speed), or by utilizing other factors (explained in this series).

It is the goal of an appropriate and effective strength training plan to safely shift the entire foce-velcoity curve, not just one end.

  1. Efficient Mechanics

Without going anywhere near what efficient mechanics actually look like, it is still important to address their influence on velocity. We have covered strength, which can enhance the capacity for power, and together, through efficient and effective mechanics, can lead to greater velocity outputs on the mound.

Two components should come to mind when considering pitching mechanics – safety and efficiency. Proper mechanics essentially mean safe and efficient sequencing of individual movements and body parts in order to optimally utilize the kinetic chain. By effectively sequencing the process of pitching a baseball, we can develop force, store elastic energy, and then safely apply the resulting forces on the baseball without any energy being lost in the process.

A couple examples of ineffective and inefficient mechanical constraints:

  • Drop a pitcher down to one knee, or even both, and ask him to throw as hard as he can. This pitcher will not be able to match the velocity of that achieved when using his actual pitching mechanics, as his lower body cannot produce much force in this position.
  • Have a pitcher face his chest toward the target. Ask him to throw as hard as possible without rotating his trunk. Without the trunk rotation, the pitcher will not be able to achieve the same velocities as that of his whole pitching motion.
  • Finally, have a pitcher tense up his throwing arm, and then try to throw it. Yet again, it will not be as effective as the whole pitching motion, as much of the elastic energy is lost by tensing the throwing arm.

Now consider the pitcher who does not lift weights or possess a great amount of force production capabilities, as we talked about when discussing strength. Despite not being as strong as many of his hard-throwing counterparts, he still may be able throw with tremendous velocity if he can utilize his mechanics as efficiently as possible, and has other qualities that positively impact velocity – like great leverage, fast-twitch neuromuscular components, etc (discussed more in detail in later installments of this series).

Now, all of this isn’t to say that strength doesn’t influence durability, tissue tolerance, and work capacity – things that can ultimately help keep the athlete safe and healthy – because it does. But, strictly in terms of velocity, efficient mechanics are highly influential as well.

  1. Exposure to Throwing Volumes

It’s important to understand that a lot of what makes up a successful pitcher is repetition. But, not just in the way you would normally consider – throwing often in order to learn and engrain mechanics so that pitch command can be optimized. There’s another outcome to consider when discussing the results that come from throwing early and often, and that’s increased pitching velocity.

Arm Pitching Machine

As we previously discussed on the topic of strength, the body responds to stimuli and stress with very specialized and specific adaptations. In the same way that our body responds to heavy mechanical loading (heavy weight) by increasing strength over time, the body too responds to the imposed physical demands on the arm and shoulder from pitching. A baseball may only weigh five-ounces, but the action of pitching a baseball is the single fastest motion that a human joint can make, with a peak angular velocity reaching upwards of 7,000 degrees/second.

This extreme motion of catapulting a ball not only takes a strong and powerful concentric muscle action, it demands an equally strong eccentric braking force out of appropriate muscles (in terms of the upper body, the rotator cuff and posterior shoulder), to slow the arm down. While the repetition of concentric muscle actions does create adaptation, especially neurological, it is the eccentric muscle action that, when combined with the extreme speed of the throwing motion, and amplified by large throwing volumes, illicit the physical and anatomical adaptations which lend themselves to increased velocity. For example…

  • With high volumes of throwing the shoulder is actively and passively taken through progressively greater rages of motion, especially into external rotation. Muscle length can be increased, but more likely passive structures (i.e. the joint capsule and ligamentous bodies) will undergo changes (which is usually accompanied by damage) that allows for greater mobility. For better or for worse, this increased shoulder external rotation in the late-cocking phase (aka “Lay-Back”) is associated with greater pitching velocities.
  • With high throwing volumes, specifically at younger ages when the bones are still developing, the humeral head (the “ball” of the “ball and socket” that is the shoulder joint) can undergo significant osseous adaptations, including what is called retroversion. Simply put, this adaptation occurs to meet the demands of the throwing motion at a young age, twisting the humeral head slightly so that even greater external rotation can occur.

The paradox of pitching, though, is that the very same stressors (high throwing volumes) and adaptations that lead to potentially greater velocities can also carry the potential of detrimental effects on the throwing arm and shoulder. Osseous changes in the bones can occur from high workloads and stress, such as bone spurring and fragmentation. Greater layback in the late cocking phase (maximum external rotation) can cause the biceps tendon to tug on the labrum, leading to some degenerative changes. Likewise, that greater mobility can lead to joint instability, which can be equally problematic.

Point being, exposure to throwing programs and high throwing volumes can influence throwing velocity. Yet, it must be understood that this is a balancing act between positive and negative adaptations.

  1. Mobility

When discussing mobility in regards to pitching velocity, we aren’t exclusively talking about the throwing shoulder. In fact, other key joints in the body also must possess adequate mobility in order to maximize the effectiveness of the pitcher’s mechanics. Namely, it is the thoracic-spine (T-Spine; the upper portion of the back), and the hips.

You’ve probably heard pitching coaches talking about hip and shoulder separation. This is essentially hip and pelvis rotation occurring through a stable trunk (lumbar spine; lower portion of the back) and a mobile t-spine. The hips must be mobile enough to rotate the pelvis while both feet are planted; the trunk must be relatively stable enough to hold firm against the torque that is then being created between the pelvis and the t-spine; and the t-spine must also have great rotational mobility to handle this position.

Mobility through the hips and t-spine also allows for adequate trunk tilt and stride length. Of course, I know better than to suggest the optimal amount of any of these mechanical qualities, but the fact still remains that without the requisite mobility, no level of these mechanics could be achieved.

Overall, it isn’t necessarily important to know how each joint’s mobility individually impacts velocity. Rather, it is more important to understand that, without adequate mobility at the appropriate joints, the effectiveness and efficiency of the kinetic chain (which is the name of the game when it comes to pitching velocity and injury reduction) will be vastly minimized.

One of two things can then result if the adequate mobility is not possessed:

1) Other segments in the kinetic chain (namely, the shoulder and elbow) will have to make up for the lagging segments (in the same way arm speed might have to make up for a lack of power production), which in turn can put undue stress on these structures, or

2) The pitcher will not reach their potential in terms of velocity because they are lacking this mobility and are unable to compensate for it in other ways.

Regardless, neither outcome is optimal. Instead, the pitcher should seek to achieve and maintain adequate mobility in order to maximize all of the other qualities that lend themselves to safe and successful pitching, as well as to high pitching velocities.

  1. Body Weight

The premise behind body weight’s influence on velocity is more or less a simple concept, and it is two-fold:

For starters, more body weight generally means more potential to produce force. Although this isn’t always the case, usually an athlete with greater body weight has more muscle mass in addition to any fat mass as compared to their skinny, rail-thin counterpart. Thus, the larger of the two is able to produce more force with greater absolute strength. Although absolute strength isn’t the end-all be-all for pitching velocity (again, see above for more on strength),it is certainly better to have the ability to produce absolute strength versus none at all.

Secondly, more body weight means more momentum going downhill toward the plate. And, while the pitching motion is about sequencing the kinetic chain as efficiently as possible to produce the greatest arm speed in a safe manner, another goal of the pitching mechanics is to gain momentum toward home plate. Thus, with greater body weight, we have the potential to accentuate that second goal.

New York Yankees starting pitcher CC Sabathia throws to the Milwaukee Brewers in the first inning of a baseball game Saturday, May 10, 2014, in Milwaukee. (AP Photo/Jeffrey Phelps)

Now, two caveats to counter the above points:

As stated in the first point above, more body weight can generally mean a greater potential to produce force. But, if this is not the case with a certain pitcher, that just means even more inertia to overcome in order to get their mechanics started and the body moving toward home plate. They simply will not be able to effectively use that increased body weight without proportional relative strength, thus their body weight may not only fail to positively influence pitching velocity, it may in fact have a negative impact.

INERTIA: a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.

Also, greater body weight and momentum through the wind-up leads to an increased demand to accept the increase in force production and momentum, specifically at landing and through deceleration. And, if the lower body, trunk, and posterior shoulder are not strong enough to accept and brake these forces, or if the appropriate joints don’t have the necessarily mobility to allow for gradual deceleration, then the body will not be able to safely utilize this greater force production.

So far we have discussed six factors that strongly influence pitching velocity. While each individual component has an impact on the kinetics of a pitch, my hope is that you are also seeing the interrelationship between each factor…

Strength can increase the potential for power, but without adequate mobility, all could be lost – or worse, the athlete could get hurt. Body weight can foster greater momentum toward home plate, but without adequate strength, increased body weight could be a detriment. Body weight, strength, and efficientmechanics may all increase the capacity for pitching velocity, but without enough exposure to throwing volumes, the pitcher may not have experienced physical adaptations that allow for the highest expression of these qualities on the mound.

7. Muscular Fatigue

Most of the factors addressed previously have a more insidious or gradual impact on pitching velocity. For example, strength and power are developed through progressive overload over the course of meso- and macrocycles (i.e. weeks, months, years), not usually microcycles (daily, or by the week). Mechanics are usually honed over time. Sustainable and safe body weight changes take lengthy periods of time as well. And, while flexibility can see acute changes, the less-transient mobility we are looking to develop takes time too. The final three factors discussed are those that have more of an impact on a day-to-day basis, or acutely.

The first we will cover is muscular fatigue. Local muscular fatigue can have an impact on velocity, both directly and indirectly.

In the more direct manner, muscular fatigue can reduce the amount of power that can be produced by the muscle through a couple of mechanisms. Muscle damage (for example, that which can be induced by eccentric-emphasis training/activity) is often accompanied by swelling around the muscle, which causes the soreness we feel. This soreness obviously elicits pain, which in turn can cause reflexes in the body to inhibit painful movement in order to avoid further damage to the muscle. Thus, you may not be able to reproduce the kinematics or kinetics of your normal delivery due to conscious or subconscious inhibitions.

We must keep in mind, though, that muscle damage isn’t always followed by soreness. Just because the muscle isn’t sore does not mean that fatigue has not accumulated. This is why it is vital to learn what training methods, routines, and throwing volumes impact your body in various ways. Over time, with a conscious effort and diligent self-evaluation, the pitcher can learn what training days have the greatest impact (positive or negative) on their throwing, and what schedules/routines best manage both their throwing and training regimens.

For example, a pitcher can learn to minimize eccentric-loaded or -emphasized exercises within a certain proximity of their next start or bullpen, thus minimizing eccentric-induced muscle damaged and delayed-onset muscle soreness.

Eccentric-Emphasis Exercise: Nordic Hamstring Curl

Concentric-Emphasis Exercise: Step Up

Muscular fatigue can also come in the form of metabolic waste, which is essentially the cellular by-products of intense training and activity. For example, there is the burning sensation that we feel in our legs as we run up multiple flights of stairs, which is a result of acidosis occurring from a build up of hydrogen ions that are produced by glycolysis. Although this is less relevant to consider in baseball (as glycolysis isn’t a major energy-producer in the sport) it still must be mentioned as it can have a direct impact on pitching velocity. I see this being more of a concern in practice where intense conditioning could immediately precedes a throwing program.

This actually can happen; I have seen it in professional baseball, where the nature of a pre-game schedule sometimes requires that pitchers participate in their conditioning prior to throwing. There have been times where I have seen relief pitchers running multiple 300-yard shuttles right before picking up a baseball to work on drills, long-toss, flat-grounds, or a bullpen session. The muscular fatigue that has then accumulated can certainly impact their throwing velocity, as well as overall work capacity and quality for that training/throwing session.

More indirectly, though, muscular fatigue can impact throwing velocity by altering pitching mechanics. This is most clearly demonstrated in-game as pitcher fatigues from inning to inning, oftentimes losing velocity as well as command. Building up work general work capacity in order to a) withstand the demands of long outings, b) recover in between pitches and innings, and c) to recover from appearance to appearance, is important to the pitcher in order to delay muscular fatigue as long as possible. But, don’t get this confused with local muscular endurance. This isn’t something we can train for by doing 3 sets of 20 repetition squats (or any exercise) with 40% of our max. This is anaerobic power (ATP-CP pathway, aka the short-term energy system) and aerobic capacity for the sake of recovery.

Ultimately it is most important to understand that smart and judicious training, diligent self-evaluation, and a commitment to recovery all play major roles in minimizing muscular fatigue each inning, each outing, and each season. And, by minimizing muscular fatigue, we can maintain an optimal state of readiness each time we take the hill (whether it be in practice or in game), thereby allowing us to express our greatest potential velocity that day.

8. Neurological Fatigue

Muscular fatigue is not the only type of neuromuscular fatigue that can be accumulated over the course of a season or training cycle. The Central Nervous System (CNS) – which includes the brain and spinal cord – can become fatigued due to high neurological demands.

The CNS – and nervous system as a whole – experiences great demand and recruitment from high intensity (heavy load) training, as well as high-speed movements. Both require the CNS to conduct electrical impulses at a very rapid rate, and utilize many motor units (each muscle fiber and the nerve cell that controls it); the only way to move a heavy object or move something at a rapid rate is to recruit as much of the muscle as possible, with as much coordination, speed, and efficiency. While this may not always lead to a burning or fatiguing sensation in the muscle itself, it will however impact performance – both in the weight room and on the field. And, it is important to understand that CNS fatigue can result from the convolution of many factors.

Credit: speedendurance.com

This is one reason why you can’t expect to throw 95 mph every single time you take the mound, even if you are capable of reaching this velocity. So many factors contribute to the readiness of the CNS (such as sleep, nutrition, workload, stress). Thus, on any given day, your nervous system may not be ready to fire at the optimal rate or efficiency.

Another example is in weight training: have you ever tried to hit your one-rep max on a certain exercise, say the back squat, multiple times in a week or two? You may hit it today, but then if you tried a few days from now, you may not come close. So many factors contribute to your readiness that day. The CNS just may not be as “primed” for that kind of intensity on that particular day.

This is exactly what makes periodization so difficult especially in season. If you did not have to factor in CNS fatigue/readiness, you could simply do high-intensity lifting (to stimulate strength and power adaptations) with very minimal volume of (e.g. 1-2 reps per set, with the goal of avoiding muscular fatigue) all season long. But, strength and conditioning coaches know that neural fatigue does actually exist, thus they must periodize training accordingly in order to create stress/overload, and then allow adequate rest and recovery to promote supercompensation (aka positive adaptation).

Finally, this is also why athlete readiness monitoring is becoming such a prevalent practice in weight rooms around the country. Strength and conditioning coaches are looking for ways to best determine if their athletes are ready to perform at their optimal level. By using questionnaires and surveys, force plates, heart-rate variability, sleep monitors, nutrition trackers, etc. the strength coach can piece together a picture of how training is affecting not just the muscles, but the athlete’s nervous system.

The biggest takeaway, though, is that the athlete must, again, be diligent in monitoring their training habits, recording their outputs (whether it be actual numerical metrics like velocity, or more subjective measures like, “How did I feel today?”), and reflect upon what works best for them. Recovery, too, from the standpoint of sleep, nutrition, and off/rest days must also be emphasized in order to illicit a parasympathetic response (in other words, a calming effect) out of the entire nervous system, which will allow for better overall recovery.

I know that this was a lot of scientific jargon, but the idea if for you, the athlete or coach, to at least be cognizant and aware of the Central Nervous System and its affect on readiness and throwing velocity. In this way you should have even greater reason to monitor your daily training, throwing, and recovery habits.

9. Intent

I will very openly admit that I don’t know sports psychology well enough to throw a ton of science or literature at you. But, I know enough about pitching, having been a pitcher, and training performance to tell you that intent is everything. Your strength, power, mechanics, body weight, mobility, readiness, etc. will mean nothing if you have no intention to throw the ball hard.

I won’t spend much time on this one, but from a physiological stand-point, it is important to understand that, much like sprinting, if you are not actively trying to move with purpose, speed, and intensity, not only will you lack purpose, speed, and intensity, but you will certainly not be stressing the neuromuscular system to make any kind of adaptation toward throwing with a high velocity. It goes back to the SAID principle discussed earlier: Specific Adaptations occur in response to Imposed Demands. Thus, if you want to throw hard, you actually have to throw hard at some point.

I’ll let someone more well-versed in psychology expand upon this topic with literature and studies that illuminate the importance of intent and purpose-driven action when it comes to performance. But, for now, just know that intent is a prerequisite for throwing hard.

This concludes the 3-part series covering nine key factors that strongly influence pitching velocity. While I tried to be as thorough as possible, it is important to note, however, that many more factors (countless, really) have an impact on ball speed.

In fact, when combined with the infinite degrees of freedom that make up human individuality, the sheer number of components that contribute to throwing velocity and pitching performance make these highly-valued athletic qualities vastly unpredictable. Regardless, it is still beneficial to know some of the influential factors that do seem to make an impact, and I hope that I illuminated at least some of these for you in this piece.

CLEVELAND — Josh Hader’s fastball is the most dominating pitch of its type in recent baseball history. And it’s a complete mystery.

The Milwaukee Brewers reliever has struck out an absurd 50 percent of batters faced this season.Through Sunday’s games.

'>1 For a single season in the pitch-tracking era,Since 2008.'>2 only two pitchers have posted higher rates: Aroldis Chapman at 52.5 percent in 2014 and Craig Kimbrel at 50.2 percent in 2012.

Pitching Arm Slot Velocity Acceleration

But what’s perplexing about Hader’s whiff rate is that hitters know what’s coming: He is going to throw his four-seam fastball. Hader turns to his signature pitch on 88.6 percent of his throws, a greater frequency than all but two MLB pitchers to have thrown at least 20 innings this year. While the pitch’s velocity (95.9 mph) is above average, it ranks just 66th among fastballs. By comparison, Chapman’s fastball averages 98.2 mph, which is sixth-best in the league.

Hader also owns a below-average total spin rate, as calculated by Statcast’s TrackMan Doppler radar component. The average spin rate for a four-seam fastball this year is 2,284 revolutions per minute, while Hader’s is a rate of 2,154 rpms. Moreover, fastballs — even mid-90 mph iterations — are generally pitches that produce some of the lowest swing-and-miss rates in baseball.

Yet batters are whiffing on 44 percent of their swings against Hader’s fastball, the top mark in the majors.Among pitchers who have thrown at least 50 four-seam fastballs, according to Baseball Prospectus.

Pitching Arm Slot Velocity Golf Ball

'>3 Another 40 percent of swings against his fastball are fouled off — meaning that an opponent is able to put a ball in play just 16 percent of the time he swings at a Hader fastball. Opponents are batting just .132 against the pitch.

Since 2008, when pitch-tracking systems were up and running in all major league parks, Hader owns the greatest career swing-and-miss rate of any pitcher on four-seamers (38.7 percent) with at least 500 fastballs thrown.

Hader’s fastball is something of a ghost pitch: It’s very difficult to hit but not for any of the usual reasons. So what makes it so effective?

Players who have faced him may have some insight. Dodgers infielder Max Muncy, who is 0-for-5 with four strikeouts in his career against Hader, told FiveThirtyEight that Hader’s arm angle makes all the difference.

“When he’s releasing the ball, it’s almost underneath his armpit, and so when he has a high-spin fastball from that angle, it really does look like it’s coming from the ground up,” Muncy said. “And then he’s throwing 97, 98 [mph] so it’s just very, very hard to get on top of that fastball.”

Muncy is right about Hader’s angle: Among lefties to have thrown at least 100 four-seam fastballs by July 14, Hader had the fourth-lowest release point but the 11th-greatest average velocity, according to Baseball Savant data.

But what about Muncy’s contention that Hader has a high-spin fastball? After all, Hader’s total fastball spin is below average. And less spin should mean less of the force in physics known as the Magnus Effect, which pushes up on a fastball, giving it the appearance of rising.Though it’s really just dropping less than a fastball with less spin.

'>4 Yet Hader does get an unusual amount of vertical movement, or rise, on his fastball — about 10 inches of itBaseball Prospectus adjusts for gravity by removing gravity-related movement from pitch movement totals.'>5 — suggesting that Magnus force is pushing up on the ball. And the rise is coming from an unusually low arm slot for such vertical lift.Pitching Arm Slot Velocity

The explanation may be his spin efficiency.

There are two types of spin: transverse spin, which is sensitive to Magnus Effect and is what makes breaking balls curve and fastball rise, and gyroscopic spin or bullet spin, which is what makes footballs fly in a spiral and is not affected by Magnus force. The problem with using Statcast’s raw spin total to evaluate pitches is that it combines both types of spin. What a pitcher cares about when trying to create movement on a pitch is his efficiency — or how much of his total spin is transverse spin.

To create perfect, 100 percent spin efficiency, transverse spin requires an axis perpendicular to the direction of velocity, while gryo spin moves parallel to that direction. (Again, think a football spiral.)

High spin efficiency likely explains Hader’s amount of vertical movement despite his low total spin. It suggests that the majority of Hader’s spin is transverse spin — which would explain the vertical movement. That’s why he can blow his fastball right by the best hitters in the game even when they know it is coming, even when it’s thrown right over the plate.

But creating such spin efficiency and vertical rise from such a low arm slot is unusual. Pitchers with lower arm slots typically release a ball with a more vertical axis that creates more side spin, like a sweeping slider from a lower arm slot. That’s in contrast to over-the-top motions that typically create an axis more parallel to the ground given the nature of their hand position.

For example, Chris Sale throws an average four-seam fastball from nearly the same arm slot (5.45 feet above the ground) as Hader (5.19 feet). But Sale’s pitch is thrown with a 126-degree axis, while Hader’s is thrown with a 147-degree axis, according to Brooks Baseball estimates, putting Hader’s axis closer to level.Spin axes pulled from TrackMan are estimates.

'>6 Consequently, Sale has some of the greatest horizontal movement in baseball on his four-seam fastball, while Hader enjoys more vertical movement than Sale does. Hader’s movement is more similar to some over-the-top pitchers.It’s important to note that estimated spin axis doesn’t tell the entire story, as two pitches could have the same axis as measured in degrees in two dimensions, but because they operate in three dimensions, one axis could be oriented more parallel toward home plate (which would create more spin efficiency), and another more perpendicular (which would create more gyro spin). Their pitch axes would measure the same in two-dimensional estimates, but their pitch efficiencies would be different.'>7

For context, Blake Snell has the fourth-highest release point for a four-seam fastball in the majors among lefties, owns a 160-degree spin axis on the pitch (more level) and ranks sixth among all lefties in vertical movement (10.5 inches). Despite Hader’s much lower release point, their fastballs move in a similar way. In essence, Hader has Sale’s release point but Snell’s fastball. Somehow it seems that Hader is able to release a ball with an over-the-top grip and/or wrist position from a side-arm slot.

“Normally that arm slot is going to create a different spin angle,” Muncy says of Hader. “That’s what makes him unique. He’s able to generate backspin from that arm slot that’s what creates such a huge advantage for him.”

What might also be helping him — and is more difficult to measure and quantify — is deception. Hader’s delivery can look like a whirl of skinny flailing arms and legs, and all that commotion can fluster opposing batters. If the opposing hitter needs a fraction of a second longer to pick up the ball out of the delivery, it’s an advantage for the pitcher.

Hader told FiveThirtyEight that when he entered pro baseball, he weighed only 135 pounds.

“For me as a young guy, just being very small, I needed all the help I could to get my arm to throw faster and harder,” Hader said of his funky delivery.

Some coaches in his amateur career and early in his pro career suggested that he change his awkward throwing motion, but the Orioles (who drafted him) and later the Brewers each had Hader undergo biomechanical evaluations, which found that his mechanics place below-average stress on his elbow and shoulder.

“This just came naturally for me,” Hader said. “I think everyone is different. Everyone has a different type of arm slot and feel.”

As for explaining his success?

“I think it’s a little bit of everything,” Hader says.

It all adds up to an offering that has become one of the most unhittable fastballs of the pitch-tracking era.

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