The Real Reason Why Weighted Baseballs Increase Pitching Velocity, and Injury Rates

Weighted ball training programs have become a very popular tool for baseball players looking to improve their pitching velocity.

Unfortunately, the popularity of weighted baseball training has grown faster than our understanding of the science behind them.

Over the last several years, Lenny Macrina and I at Champion PT and Performance have teamed up with Dr. Glenn Fleisig and Dr. James Andrews at the American Sports Medicine Insitute to try to learn more about the safety and efficacy of weighted baseballs.

Over a series of research projects, we’ve learned a lot over the last few years. But, there are still many questions related to the safety, mechanism, and efficacy of weighted ball usage in baseball. 

We’ve learned that throwing weighted baseballs changes the stress involved on the arm

Dr. Fleisig examined the biomechanical effect of throwing weighted baseballs in a group of high school and college pitchers. 

The authors noted a significant increase in elbow varus torque (stress on the Tommy John ligament) when throwing weighted balls on flat ground with the run-and-gun technique compared to throwing off a mound. 

Okoroha showed a similar increase in elbow varus torque in a group of youth baseball pitchers throwing flat ground.  They documented a statistically significant increase in stress as the weight of the ball increased.

We’ve learned that injury rates are higher in baseball pitchers that perform a weighted ball program

Our study was the first to examine injury rates during and following a weighted ball throwing program.  

While we did show a 3.3% gain in pitching velocity, we also showed a 24% injury rate in high school baseball pitchers who performed a 6-week weighted ball program.  There were no injuries in the control group that did not perform weighted ball training and only focused on normal weight training.

And while we did show that velocity increased, it wasn’t in all the pitchers, and 67% of the control group also showed an increase in velocity just by basic throwing and weight training.

It’s important to note that we followed our players for the season after performing an offseason weighted ball program. We see far more injuries in the season after than while actually performing the weighted ball program.

We also think we’ve learned why we see both velocity gains and higher injury rates

More importantly, I really believe that we learned a lot about the mechanism of both the increase in velocity, as well as stress and injury rates, from weighted balls. I’ve tried to summarize this in some articles on the science of weighted baseball training programs.

We were surprised to observe a significant gain in shoulder external rotation range of motion (or layback). 

Pitchers in the program showed a significant gain of 4.3 degrees of shoulder external rotation after the 6-week program.  The control group did not show this change.  And we know from several previous studies that the amount of layback is correlated to both increased stress and velocity in baseball pitchers.

Weighted baseball training programs may be effective at increase pitching velocity, but they also increase shoulder motion, stress on the elbow, and injury rates

After we found that external rotation of the shoulder increased after performing a 6-week weighted ball program, our first thought was that we needed to study the immediate changes after throwing weighted balls to see if this was something that works right away or needs weeks of training to observe.

Which leads us to our latest study.

The Immediate Effects of Weighted Baseballs on Shoulder Range of Motion

In our latest study that was published in Sports Health, we wanted to see what happens to shoulder range of motion immediately after throwing weighted balls.

To study this, we looked at a group of 16 high school baseball pitchers with a mean age of 17 years old. We measured their shoulder range of motion before and after a weighed baseball training session to assess what changes occurred on that one day.

Because there are many different weights of baseballs used in the common training programs, we also wanted to see if there was a difference between the weights of balls used. So we broke the study into 3 different test sessions.

The pitchers came to our facility on 3 separate days to perform the 3 different training sessions:

  • Underweight baseballs using 2oz, 4oz, and 5oz balls
  • Overweight baseballs using 5oz, 6oz and 9oz balls
  • Extreme overweight baseballs using 5oz, 16oz and 32oz balls

Each pitcher threw 3 throws with each ball in 3 different positions:

  • Kneeling throws
  • Rocker throws
  • Run and gun throws
weighted baseball velocity program

So, in total, each testing session threw 3 throws from 3 positions with 3 different ball weights for a total of 27 throws. That’s not a lot for one session. People often do a lot more than that in reality.

Immediately after each throwing session, we measured their shoulder range of motion again. After just this small amount of time and throws, we didn’t expect to find many differences in range of motion.

This proved correct when we looked at players after throwing underload balls. There was no change in range of motion. This serves as a good baseline for the rest of the findings, the only variable we changed in the other sessions was the weight of the balls, so any changes we find can be attributed to the weighted balls themselves.

As the weight of the balls started to increase, so did our findings. With the overload balls of 6oz and 9oz, we started to see a change in shoulder external rotation range of motion, or layback. As the weight of the balls increased, so did the amount of external rotation gained from throwing. With the overload balls, external rotation increased by over 3 degrees, but with the extreme overload balls of 16oz and 32oz we saw an alarming increase in over 8 degrees:

Acute effect of weighted baseballs on shoulder range of motion

I can’t stress enough how important that finding was in this study. Lenny and I literally looked at each other while we were measuring range of motion and were shocked.

One thing to keep in mind with any research study is that these values are the averages of the groups. When you break down the numbers per person in the study, the results are even more valuable. Realistically, the level of intensity of the throws may alter the results. If a particular pitcher doesn’t throw with a lot of intensity, it could skew the data. This could happen with people that aren’t used to throwing weighted balls.

For the overload session of 6oz and 9oz balls, you can see that some players’ range of motion didn’t change much, but a trend towards this increase. For those that did increase, there were many that increased more than 5, 10, and even 15 degrees of external rotation, with an average of over 8 degrees:

weighted baseball training increases range of motion

So even though the 3.3 degrees mean change in external rotation was statistically significant, it could be even more clinically relevant than even this study suggests. I personally consider this 3.3 degree change to be the baseline, with many players increasing more than that.

When you look at the extreme overload session of 16oz and 32oz throws, the results are even more revealing. The large majority of subjects went up, and went up by a lot:

The effect of weighted baseball training

So again, while the mean of 8.8 degrees was statistically significant, the clinical implications are even higher, the majority of players increased external rotation by 10-20 degrees.

This finding is alarming and something that everyone needs to understand if you use or recommend using weighted balls to develop pitching velocity.

Throwing with weighted baseballs increases your external rotation rapidly by a lot. The heavier the ball, the more the range of motion increases.

But… But… But…

As with my past research, many people have read our findings and not been happy with the results. Perhaps the results challenge their bias and past beliefs? Or maybe they just don’t want to know the science.

So many people have tried to criticize our methods.

Remember, we have no bias. We are the scientific people trying to study these weighted ball programs. We do not profit off them (until you get injured!). We just want to know the science, we really have no preference as to what the data says. I’m as surprised as you are with the results.

I want to address the common things we hear about our studies:

  1. We included run and guns with a 2lb ball. Unfortunately, this is happening in the real world. Kids are doing this. I’m glad that some people think this is a little crazy, I kinda do too, but the goal of our studies is to assess the spectrum of programs that are out there in the real world. But please keep this in mind… there were only 3 throws with a 2lb run and gun. That’s not a big deal. That’s 3 throws out of 81, or less than 4% of the study. Let’s not throw out the other 96% of the study.
  2. Player’s weren’t prepared for a weighted ball program. This isn’t true. All players in our studies had been adequately prepared by performing a baseball-specific training program and a several week ramp-up throwing program prior to these studies.
  3. Player’s weren’t familiar with weighted ball programs. This may be true for some of the subjects, but not all. But again, we wanted to simulated the real world. You have to start training with weighted balls at some point when you first start a program.

I sincerely do not believe any of these factors are very relevant and certainly do not limit the clinical value of our findings.

Why Does External Rotation Increase?

shoulder external rotation ROM layback

I’ll start this section off pretty clearly: We don’t really know.

But, we have some very plausible educated guesses based on our scientific evidence.

To be honest, I was personally very surprised to see that external rotation increases from weighted balls. But now that we know this, it absolutely makes sense.

But why?

There are likely two reasons why external rotation increases after throwing weighted balls:

  1. Acute changes to the neuromuscular system
  2. Chronic cumulative damage to the musculoskeletal system

Weighted Balls Cause Acute Changes to the Neuromuscular System

The rapid gain in external rotation was surprising. I don’t think this typically represents significant trauma to the shoulder, like tearing the capsule or muscles (more on that below…).

What is most likely happening is that we are desensitizing the proprioceptors, the Golgi tendon organs (or GTOs), that are designed to detect stretching and fire our muscles to protect from overstretching.

These GTOs detect when our joints are getting to the end of their range of motion and trigger the opposing muscles to slow down the movement to protect yourself.

golgi tendon organ
Photo from Wikipedia

Desensitizing this mechanism can lead to increase mobility, but at what cost?

This is a defense mechanism within our bodies. Without it, our throwing shoulder and elbow are susceptible to more stress.

In the physical therapy and training worlds, we actually use this to our advantage at times. Plyometric exercises, dynamic stretching, and techniques like contract-relax all work on this premise.

When you stretch your hamstrings and feel looser immediately after, it’s not because your hamstrings got longer after a few seconds of stretching. That structurally doesn’t make sense. It’s because you’ve desensitized the stretch reflex of the hamstrings.

This is usually not a big deal, but when you are doing it to push the extremes of your physiology and then pitch on it, it becomes more significant. Pitching already puts a ridiculous amount of stress on your arm.

Weighted Balls Cause Chronic Cumulative Damage to the Musculoskeletal System

Luckily, I think the primary reason why we are seeing the change in external rotation is from the acute desensitization of the proprioceptors we just discussed.

However, it would be short sighted to also not consider some chronic damage, especially if pitching with this increased external rotation.

During the pitch, the arm rapidly transitions from external rotation to internal rotation to start accelerating the ball. This places tremendouse stress of the static and dynamic stabilizers of the shoulder.

baseball pitching biomechanics - max external rotation layback

Statically, this can damage the anterior capsule of the shoulder. You don’t want this.

Dynamically, we are seeing damage to the muscles that need to eccentrically slow down the layback and transition to arm acceleration. These muscles include the latissiumus dorsi, teres major, pectoralis, and subscapularis muscles.

Have you noticed how common lat strains are in baseball now? We rarely saw this 10-20 years ago.

The acute changes are likely also leading to chronic cumulative changes.

So What Does All this Mean?

So now that you know way more than you probably ever wanted to know about shoulder external rotation, let me explain why this matters.

Quite simple, we know that the more external rotation you have the more velocity you have. We also know this increases the stress on your shoulder and elbow.

This is the part that sounds like rocket science, but is actually common sense. It’s physics. More layback allows the arm to throw harder, which puts more stress on the arm.

baseball pitching layback external rotation
Image from Wikipedia

Duh, right? Makes sense now, right?

Most of the proposed theories on why weighted balls helped increase pitching velocity are likely not true. The gain in layback is the primary reason, no doubt in my mind.

Weight ball programs do not increase arm speed, do not increase arm strength (in fact we showed they inhibit strength development), and do not do any of the other things that have been proposed. We have now officially studied this all and concluded this with our research.

Weighted balls increase layback, which increases velocity, which both increase stress, which all increase injury rates.

Again, makes perfect sense now, right?

Do We Even Need Weighted Ball Training Programs?

OK, I get it, you still want to use weighted balls. They seem magical on the internet.

I’m completely fine with that. I use them myself with many of the players we work with, however not all of them.

As we continue to learn more, I think we realize that weighted balls have a very small place in our velocity development programs for the right person at the right time.

They should not be performed blindly on a big group of people, like we are seeing being implemented for youth, high school, and college teams across the country.

This is silly.

As with everything else in life, it’s all about the dosage. Ever hear the phrase “there’s too much of a good thing?”

We are really overdosing on weighted balls.

But I’m going to end this article with a question… do we even need weighted ball training programs?

I’m not talking about substituting weighted ball training with many of the things that have been proven to enhance velocity without causing injuries, like strength training, power development, arm care, and proper biomechanics. I’m talking about do we need to be doing these elaborate weighted ball training programs all offseason.

Based on this current study, if layback range of motion increases so much so quickly, and more layback means more velocity than maybe all we need is a quick and simple warm up with a weighted ball.

This could give a small stimulus to desensitive your propioceptors enough to allow a little more layback and a little more velocity, without having the put the body through weeks of a weight ball training program.

This sounds a lot safer on the body to me.

This also sounds like our next study that is in the works. Stay tuned… :)

The Effect of a 6-Week Weighted Ball Training Program on Baseball Pitchers

Sports health cover pageI’m very proud to say that our first research project on the effect of baseball pitchers training with weighted balls has finally been published!  Big thanks for my coauthors Lenny Macrina, Dr. Glenn Fleisig, Kyle Aune, and Dr. James Andrews.

By now, many people have seen the results of the study.  I’ve presented the data at APTA, ASMI, PBATS, Sabermetrics Seminar, and many more as we went through the publication process.  We felt this study was very important for the game of baseball as we have seen such a large growth of interest in weighted ball programs, without a complete understand of what happens to the body.

I believe we have found the mechanism behind why throwing weighted balls enhances velocity.  It’s not a change in biomechanics, arm speed, or strength.  It’s a gain in layback.  This likely also explains why these programs are more stressful and show higher injury rates.  I’ve written a summary below, but I urge you to read the full study for all the details:

The Effect of a 6-Week Weighted Ball Training Program on Baseball Pitchers

The Effect of Weighted Ball Training on Baseball Pitchers

We performed a 6-week weighted ball training program with high school baseball pitchers.

Players gradually ramped up over the 6-weeks to include kneeling, rocker, and run-and-gun throws with balls ranging from 2oz to 32 oz.  All participants had been throwing and weight training prior to prepare for the program.  We modeled this off very commonly performed programs.  We feel that this program, if anything, is more conservative than many of the programs we have seen.  Many other programs are longer, have less of a ramp up, and include balls that are even heavier.  Also realize that throwing a heavier ball with less intensity over a longer period of time is likely more stressful on the body, it’s just physics.

The max weight, 32oz, was used for a total of 18 full effort run and gun throws.  This represents only 3% of the total balls thrown over a 6-week period.

A control group was used that did not perform the weighted ball program.

After 6 weeks, the weighted ball group did increase velocity by 3.3%.  It should be noted, though, that 8% showed no change, and 12% showed a decrease in pitch velocity. Furthermore, 67% of the control group also showed an increase in pitch velocity.

Arm speed and arm strength did not increase, and biomechanics did not change, meaning the gain in velocity was not from any of these commonly theorized reasons.  In fact, arm strength was up in the control group, suggesting that a weighted ball program may actually inhibit strength gains.

The weighted ball group showed almost a 5 degree increase in shoulder external rotation, or layback.  This has been correlated in previous studies to both velocity and stress on the arm.

The weighted ball group had a 24% injury rate.  Half of these did not occur during the study, they occurred the next season, which is an important finding.  There were no injuries in the control group.

The Road to Publication

Many people don’t know what happens in the background when conducting studies with sound methodology and peer review with a prestigious journal.  So I thought I’d share that process.

It takes weeks to months to go through a credible IRB to assure the project is designed well.  It then takes months to conduct the trials to actually acquire the data.  This has to be planned well to assure consistency and valid data.  It takes weeks to analyze the data, going back and forth with the statisticians to sort through the results to pull out the clinical implications.  It then takes months to write the manuscript, remember we are clinical researchers, mean we actually work with clients in the day!  We write these in our spare time at night and on weekends.  The manuscript is then submitted to a journal, which takes months to get back to you, they likely have hundreds on manuscripts submitted per month.  You then work with 3 peer reviewers that take a hard look and criticize the paper.  Their goal is to assure the results are reliable, valid, and without bias.  You then go back a forth a few times over several months.  At this point in time >90% of articles have been rejected, so if you’ve made it this far, congrats!  The editor now takes over and we have another back and forth to assure the results are clear and everything is in order.  The publisher then reaches out with page proofs for you to approve.  Then, magically one day, you get an email with a PDF attached and a link to the publication!

Exhausted just reading that?  Yup, me too.

It’s a LOT easier to just type away and hit publish on a blog, but so many questions are unanswered when that happens.  Was the study designed properly?  Did the procedure follow sound methodology to assure the results are valid?  Were the methods reliable?  Was there no bias from the authors?

That’s why we felt it was so important to get this data out to the scientific community in a medical journal.  Doctors, physical therapists, athletic trainers, and strength coaches need to understand the effects of weighted balls when designed injury prevent, performance enhancement, and rehabilitation programs.

Should You Use Weighted Balls?

Weighted balls are not evil.  They are not the cause of injuries.

Throwing itself is the cause.  Weighted balls just change the stress to the body.

They can be used strategically if you understand this and build a program that takes the science into account.  However, remember there’s more than velocity when it comes to pitching.  And science also tells us that there are MANY other ways to enhance velocity that are much less stressful.

Weighted balls are just another tool for us to be used with the right person, at the right time.  But that is probably less often than you think.  If you are a coach using these programs, you must understand this.  There are so many teams now just starting a generic templated program for all players.  There is a better way.

The Future of Weighted Ball Research

This study was phase one.  We wanted to look at the results of a 6-week program that is commonly performed in high school players.  This study has shown us a few very important things and has brought to attention what I believe is the primary reasons weighted balls increase velocity (and injury risk).

We have already finished phase two and phase three.  Phase two will look at the effect of different positions and ball weights on the arm, mechanics and velocity.  This study will help us understand which positions and balls to use.  Phase three will look at the immediate effect of different ball weights on the arm.

Together these three studies will shed a lot of needed light on the use of weighted balls.

Once these papers are finalized, the important part starts.  We’ll then work on a clinical commentary paper that summarizes all of our past studies and the science of weight balls.  This will be extremely valuable, and an import resource for baseball coaches, parents, and players to read.

There are still many questions to be asked.  It’s almost impossible to answer them all, but we are lot closer to understand the true science behind baseball pitchers training with weighted balls.

Help Spread the Word

Want to help?  I hope so.  Trust me, we are very busy at Champion PT and Performance with baseball injuries.  But nothing would please me more than reducing injuries and helping baseball players take it to the next level.  How’s that for sincerity.

This info needs to get to the baseball coaches, players, and parents.  Please share and spread the word.  Thank you!

The Science of Weighted Baseball Training Programs

Weighted baseball training programs to enhance pitching velocity are becoming more popular each year.  However, there are so many questions regarding the proper use of  weighted baseballs:

  • Are weighted baseball training programs effective at improving pitching velocity?
  • If so, why do weighted baseball velocity programs work?
  • Does everyone gain velocity with weighted ball programs?
  • Are weighted baseball programs safe for everyone to perform?
  • Do we know the long term implications of these programs?

We still do not know many of these answers.  There are a bunch of great facilities around the country that are pushing the limits with not only training with weighted baseballs, but also attempting to collecting data to help answer some of these questions.

We are getting better everyday, but there is still a great need for more information.  Like anything else, the pendulum is swinging towards the side of pushing the limits.  I’ve discussed this in a past article on baseball velocity programs and essentially noted that I felt we have not found out the most appropriate dose, and are simply are overdosing.  We need to fully understand the science of these programs before we let this swing too far.


The Science of Weighted Baseball Training Programs

We have just recently finished a 2-year study looking at the safety and effectiveness of weighted baseball training programs at Champion.  Lenny Macrina and I conducted the study in collaboration with ASMI, Dr. Glenn Fleisig, and Dr. James Andrews.

This is the first real research study looking at the way a 6-week weighted baseball training program effects pitching velocity, arm stress, range of motion, strength, and most importantly, injury rates.

The results are eye-opening for sure.

As many of you know, planning, conducting, and publishing a real research project takes time, often years from the beginning to the eventual publication.  It must go through a strict review to assure safe methodology and a lengthy peer-review process to assure there is no methodological flaws or bias that may be skewing the data.

It’s great that many people around the internet are discussing the data that they collect at their facilities.  This is a great first step in becoming better as a group of professionals.  but without careful scrutiny of their research design, methodology, statistical analysis, and results, it’s tough to call that data “research.”  There are so many variables that could skew the data, it’s hard to draw accurate conclusions.

Our project has been presented at numerous scientific meetings and is currently submitted for publication.  It’s actually been nominated for the Sports Physical Therapy Excellence in Research Award.

Are Weighted Baseball Velocity Programs Safe and Effective?But because it takes so long to get to publication, I wanted to write a summary of our findings.  I recently published this on, an amazing website I have started dedicated to providing trust worthy information to advance the game of baseball.

Click below to read my summary of our research project on EBP, and please be sure to share this with any baseball player, parent, coach, rehab, or fitness specialist that may work with baseball players:



Are Baseball Velocity Programs to Blame for the Rise in Pitching Injuries?

do velocity programs cause pitching injuries

One thing is certain when it comes to baseball pitching injuries, they are rising.  Another thing is also certain, baseball velocity programs are ridiculously popular to enhance pitching velocity.

This winter I was honored to be a speaker at both the Professional Baseball Athletic Trainers Society Medical Meeting and the American Sports Medicine Institute Injuries in Baseball Conference.  In both meetings we spent countless hours discussing the rise in injuries and what we can do to help reduce these alarming rates.

I believe the biggest thing we can do is educate, and that is the intent of this article.

Recent reviews of Major League Baseball data have shown that 25% of all pitchers in MLB have had Tommy John surgery.  I’ve written in the past about why Tommy John injuries are rising in Major League Baseball.  While this is amazing to begin with, a scarier trend is also emerging.  86% of MLB pitchers had their Tommy John surgery while playing professional baseball.  However, 61% of all minor league baseball players had their Tommy John surgery during high school or college.

Pitching injuries are occurring at an earlier age.

A recent study in The Physician and Sports Medicine showed that 30% of youth baseball players up to the age of 12 reported episodes of shoulder or elbow pain.  Another report in the Journal of Arthroscopy noted 31% of pitchers up to the age of 22 have experience an arm injury.

Dr. Ahmad of the New York Yankees reported in the American Journal of Sports Medicine on the rise in Tommy John surgery over a 10-year period in the state of New York.  The volume of surgeries increased 193% between 2002 and 2011.  Plus, there was a statistically significant trend towards the age of surgery going down, meaning that more and more kids are having Tommy John surgery at an earlier age.

Dr. James Andrews, who has done more Tommy John surgeries than anyone else, has been discussing how he is seeing a rise in Tommy John surgery in youth baseball pitchers.  At meetings, he tells the story of how he used to see just a few kids a year, but now over a third of Tommy John procedures he performs are in youth pitchers.  Here is a graph showing the rise in Tommy John surgeries performed each year by Dr. Andrews:

tommy john surgery youth

Why Do Baseball Pitching Injuries Occur?

Over the years, we have hypothesized many potential causes of the rise in injuries in baseball but the research keeps coming back to two primary causes of pitching injuries:

  • Overuse
  • Increased velocity

Pitchers that throw more innings, more pitches per game, more games per week, play for multiple teams, and participated in more showcases have all been shown to have higher injury rates.  But it’s not just overuse during the season, it’s overuse throughout the year.  In a landmark study by ASMI, pitching for more than 8 months out of the year resulted in a 5x greater chance of sustaining an injury.  This is significant.

Combining all the great research now available to us, here is how the chance of youth baseball injuries increase due to overuse:

  • Pitching > 100 innings in one year = 3x greater risk of injury
  • Averaging > 80 pitches per game = 4x greater risk of injury
  • Pitching > 8 months per year = 5x greater risk of injury
  • Regularly pitching with arm fatigue = 36x greater risk of injury

Our trend towards emphasizing velocity more than any other pitching attribute is not helping either.  Two studies, one in the American Journal of Sports Medicine and the other in Sports Health, have shown a correlation between velocity and elbow stress in high school and professional baseball pitchers.

While increased stress on the Tommy John ligament does not necessarily mean they will get injured, ASMI has also noted that velocity correlated to injuries and that pitchers that threw harder had a 2.6x greater chance of getting injured.  In the previously mentioned article in Arthroscopy, an increase in velocity was associated with a 12% greater injury risk.

So it makes sense that we are seeing a rise in both the average pitch velocity in Major League Baseball and the number of players undergoing Tommy John surgery:

tommy john surgery correlates to pitching velocity

Essentially, the harder and more often you throw, the higher your chance of injury.  

Many people are perfectly OK with accepting this risk, and I am too.  But, the fact that throwing a baseball is not good for your body is very apparent and the first thing that we must all understand when designing baseball training programs.

The Evolution of Baseball Training and Velocity Programs

I believe we are in what I would call the “velocity program” era of baseball training.  The primary focus of every kid in America is on performing a “velocity program” that they saw on the internet and essentially guarantees a huge increase in velocity.

The internet is filled with a lot of information.  This is a great thing and allows us all to learn at a rapid pace.  However, it’s difficult to determine who we should actually be listening to and trusting.  Often times the most articulate writers with the most impressive videos will get the most exposure.  What we are seeing is a blind trust and faith in these recommendations based on anecdotal information and limited science.

This is a huge problem to me.  The science is not adding up.

The two biggest offenders I see right now are weighted ball and long toss programs.  These programs have become popular.

Below are the Google search term trends for “weighted baseballs” and “increase baseball velocity” from 2004 to February 2016.  You can see a trend upward as well as the rise in popularity of weighted baseballs over the last few years:

increase pitching velocity

Let me be clear and get this out of the way.  I am a believer of performing weighted baseball and long toss programs.  I incorporate them into my programs and think you should too.  (No one will remember those last two sentences, by the way).

It’s not the program that is the problem, it’s how these programs are being implemented.

It all comes down to “dosage.”  We all know that medicine is effective.  But there are side effects to all drugs and, more importantly, you can overdose and cause more harm than good.

I believe we are overdosing on velocity programs.

We are putting a lot of faith into programs being marketed on the internet that have not been validated scientifically to be safe or effective.  Again, just to be clear, there are many smart coaches on the internet with great programs.  I follow many great minds and really respect what they do.  But realize that:

  • People are trying to implement these programs on their own without thought or a clear understanding on what is safe and effective.  They are not selecting the appropriate dose.
  • People are implementing the same velocity program for everyone, often on a team-wide basis, not individualizing the dose for each individual.
  • People are getting greedy.  Many people think if a 1 lb ball can help them gain 3 MPH, than a 2 lb ball can help them gain 6 MPH!  They are overdosing.

We have a very limited understanding of the science weighted baseball, long toss, and other baseball training and velocity programs, but research is starting to come out.  Below is what we currently know regarding weighted ball and long toss programs.

If you are going to start a pitching velocity training program yourself of with athletes, you MUST understand the science.

The Science of Weighted Ball Velocity Programs

Weighted ball training programs work.  We have enough evidence to know that weighted ball training helps to increase pitching velocity.  We’ve known this for decades.  But at what cost?

I can tell you from my experience as the person on the other side of the equation, I hear this comment all the time from injured baseball players: “I started a weighted ball training program this winter, gained 3-5 MPH on my fastball, and then hurt my arm for the first time during the season.”  I can’t tell you how common that is at Champion every day.  This is all I do every day.

How about this conversation I recently had:

  • Pitcher: “I hurt my shoulder two weeks ago and can’t throw without pain.”
  • Me: “Have you ever hurt your arm before?”
  • Pitcher: “Never.”
  • Me: “Did you do anything different this offseason?”
  • Pitcher: “I started an aggressive long toss program to 300+ feet and weighted ball program.”
  • Me: “How did it go?”
  • Pitcher: “This is the best my arm has ever felt.”
  • Me: “Wait, you just said you can’t throw because of pain for the first time, sounds like this is the worst your arm has ever felt.”
  • Pitcher:  [blank stare…]

As you can see, his perception may be the biggest part of the problem.

**Update – since the writing of this article, I have been working with this same athlete.  We toned down his program completely, building up his body and strengthened his arm.  After that, and only after that, did we start a much milder version of a velocity program with long toss and low dose/frequency weighted balls.  His velocity is up even MORE this year and his arm feels great, but I really wanted to share the message I got from him: “Hit 92 MPH the other day, I guess less is more!”  

We still don’t know how safe these programs are and, more importantly, what the effective “dose” should be to increase pitching velocity.  What I mean by this is, how heavy, how light, how many throws, how often per week, and how much during the year among other questions.  Selecting the right dose is important, and it should start with the minimum viable dose to achieve a training effect.

We still do not know the safest and most effective “dose” for pitching velocity programs, just like medicine, more is not better. [Click to Tweet]

The first study to look at the biomechanics of weighted ball programs has been submitted for publication by Dr. Glenn Fleisig and ASMI.  Dr. Fleisig presented the results of their study at the ASMI Injuries in Baseball Course.  Their study looked at mound vs. flat ground throwing of 4, 5, 6, and 7 oz balls.  Although limited in what was evaluated, they showed that throwing balls less than a 5 oz regulation ball increased the amount of stress on the arm.

What tends to happen with overload balls is less stress but over a longer period of time, and for underload balls it’s more stress over a shorter period of time, which is a bad combo.  Sorry for my crude drawing but here is a graphic visualization of this concept:

weighted ball velocity training stress curves

The 7 oz throws were less stressful than a regulation ball, however, we still don’t know if this changes as the balls get heavier or if they change with more intense run-and-gun or turn-and-burn style throws.  These were not studied.  I think they do.

We have recently finished up a big study at Champion PT and Performance where we have teamed up with ASMI, Dr. James Andrews, Dr. Glenn Fleisig, and Motus Global to research weighted ball programs.  In the first phase of the study we are using knee throws, rocker throws, and run-and-gun throws using between 2oz and 2lb balls.

I’ve recently published the whole summary on this study, which you should definitely ready:

We found that weighted baseball programs can be effective at enhancing velocity, but at what cost?  We have a 24% injury rate, which we feel was due to significant increase in shoulder external rotation range of motion.  That’s not good.  Furthermore, performing a weighted baseball training program did not increase arm strength, arm speed, or mechanical changes.

Unfortunately, this is was my hypothesis.  Weighted ball programs using weights more than 5oz are effective at enhancing velocity.  I believe this may be because it causes such a quick and dramatic increase in external rotation, or layback.  Increasing this layback correlates to greater velocity.

Weighted baseball training programs may be changing out anatomy.

Scientifically, this gain in external rotation is not from a muscle stretching or the bone adapting.  It wouldn’t happen that fast.  What is likely happening is that the static stabilizers that are supposed to prevent excessive external rotation are being damaged.  This could be the capsule, labrum, or even rotator cuff.  These are not injuries that you want.  Plus, as layback increases, so does stress on the Tommy John ligament.

This is why many people do not get hurt during a weighted ball program, but end up getting hurt down the road.  They’ve pushed past their normal anatomy to increase pitching velocity.

So weighted ball programs have two potential concerns:

  1. Overweight balls may be causing damage to the tissue of the shoulder to allow more layback.  This gain in layback may also increase the strain on the Tommy John ligament (among other things).
  2. Underweight balls increase the amount of peak strain on the arm.

The Science of Long Toss Velocity Programs

In addition to weighted ball programs, we have also seen an increase in baseball long toss programs designed to improve pitching velocity.  Long toss is nothing new, but throwing maximum distance and trying to extend this distance over time has become more popular.

Similar to weighted ball programs, we are starting to see studies published quantifying the stress observed on the throwing arm during long toss throwing.  You have to take the science of long toss into consideration.

Dr. Fleisig and ASMI evaluated the stress observed during long toss programs in past studies.  One of these studies, published in the American Journal of Sports Medicine, studied the difference between pitching off a mound and long tossing at 120 feet, 180 feet, and at maximum distance.  Long tossing to 120 feet had similar stress on the arm as pitching on the mound.  Throwing to 180 feet had greater stress.

However the most alarming finding of the study involved throwing maximum distance.  When subjects were asked to use a crow hop and throw as far as they could, the stress on their arm increased by 10% more than pitching off the mound (and their mechanics changed too…)!  It should be noted that the mean distance thrown was 264 feet, less than what many people throw.

Another recent study publish in the American Journal of Sports Medicine by Dr Elattrache of the Los Angeles Dodgers showed no significant difference between pitching off the mound and long toss throwing between 60 and 180 feet.  Let’s be really clear on this one, the amount of stress on the shoulder and elbow were the same as pitching off the mound AND throwing flat ground from even as short as 60 feet, despite a significantly lower velocity during the throw.  Perhaps throwing flat ground is less biomechanically efficient.

It is apparent that the longer you throw, the more stressful it is on the arm, even more so that pitching off the mound.

Long toss is important.  But again perhaps we are using the wrong dose.

I for one have worked with many players that love long toss and many players that hate long toss.  I’ve worked with MLB All-Stars and Cy Young winners on both sides.  I have worked with some that can easily throw 250+ feet without any sign of altered mechanics, while others labor at 180 feet.

Perhaps our issue is more related to the fact that one magical long toss program doesn’t exist.

Trying to say that a certain distance is recommend for everyone is very disadvantageous.  Everyone is different.  Think about it this way, should a 5’8″ tall pitcher and 6’6″ tall pitcher throw the same distance?  Should a sidearm pitcher throw the same distance as someone more over the top?  Should a 15 year old skeletally immature kid throw as far as a 30 year old big leaguer?

Long toss programs need to individualized for each person.  Similar to weighted ball programs, we now know that the stress on the arm exceeds pitching off the mound.

Do We Want to Expose the Throwing Arm to Increased Stress?

I think we do.  The body is a really amazing thing.  It’s really good at adapting to applied demands.  We’ve shown scientifically that:

  1. If you throw too MUCH when your growth plates are open, you place too much stress on the arm and greatly increase your chance of injury
  2. If you throw too LITTLE when your growth platers are open, you don’t apply enough stress to develop the physical ability to throw hard when you are older

Exposing the body to increased stress is a good thing.  This is how it adapts.  But just like a rubber band, if apply put too much stress or too many repetitive stresses, it will snap.

We need to expose the throwing arm to increased stress.  I don’t think the real problem is that these weighted ball and long toss velocity programs apply more stress on the arm.  That may be advantageous to an extent to build load tolerance by exposing the body to this extra stress.  It again just comes back to dosage.

These imposed demands need to be applied scientifically with the appropriate intensity, volume, frequency, and timing during the year.  This is not happening.

Are Velocity Programs to Blame for the Rise in Baseball Pitching Injuries?

I don’t think velocity programs directly to blame for the rise in baseball pitching injuries.  It’s not the program, it’s the dose.

So what we know right now is that both weighted ball and long toss programs produce more stress on the arm than pitching off a mound.  Again, this is acceptable if applied appropriately, and in fact this may be desired.

But let me ask you a couple of big questions:

  • Would you throw a bullpen 6x per week?
  • Would you throw bullpens all year around?

I hope you said “no” to both of those questions.  If not, you have a lot of reading to do.  Remember, pitching for more than 8 months per year has been shown to result in a 5x greater chance of injury.  A staggering number.

Most coaches know this and have started to throw less bullpens with their pitchers over the offseason.  However, bullpens are being replaced with weighted ball and long toss velocity programs.  Some are even doing this all offseason, while others continue to do this during the season.

So if the science is showing that both weighted balls and long toss place MORE stress on the arm than pitching off a mound, why would you do this 6x per week and why would you do it all year round?

We aren’t resting enough.  Remember what we said before, throwing a baseball is bad for your body.  You need to build in proper rest for recovery.

Your body does not care what or how you are throwing.  It just cares about the stress that is being applied to the tissue.

There is a place for weighted ball and long toss velocity programs, our programs we have built at Champion PT and Performance include these training techniques.  But these should be individualized and applied appropriately using what we know scientifically about these programs.

I believe many are overdosing on these velocity programs and this is one of the main reasons that despite all our advancements in baseball training programs, injury rates in baseball continue to rise.

I wrote this article because I work with injured baseball players all day, and it pains me to do so.  I sincerely want to be put out of business.  I am worried that we are hurting our youth and I see this trend only getting worse.

Elite Baseball Performance

As we continue to learn and develop our programs, I am going to share them.  I actually have a lot of baseball content coming and a couple of surprises on the way.  I have recently launched a new website dedicated to advancing the game of baseball at  I have put together an amazing group of advisory board members and contributors, including people like Dr. James Andrews, Dr. Glenn Fleisig of ASMI, MLB players like Josh Beckett and Craig Breslow, and several baseball coaches, athletic trainers, strength coaches.

My goal is simple, to provide cutting edge and TRUSTWORTHY information to advance the game of baseball.

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Photo by Joel Dinda