Weighted Baseball Training: Results from 2012 and a Case Study

About a year ago, I made my free ebook on weighted baseballs available to the public. Since then, we’ve had over 2,000 requests for the book, and many followed up on their results. Here’s a few of the responses I’ve gotten back:

I have followed your weighted baseball program with four of my students and I have had great success with increased velocity and overall arm strength. Great overall program and very well laid out, an excellent addition to my “toolbox.”

-Steve S.

It works. My god does it work! I’ve picked up 8mph according to my own radar gun. I don’t get injuries… which is the best part. Started at 83mph, now I’m Consistent at 91.


We loved the approach and we’re hoping to apply it internally in winter ball. Please let us know when your book on training pitchers is available.

-National Crosschecker for an MLB team

I integrated it into our offseason training program with good results. The best results came from our relievers, who picked up an average of 3.5 MPH. Starters responded OK to it and none lost velocity, but our closer and our bullpen guys really took to it. I think it’s because they have a far more aggressive mentality. Thanks!!

-Division-I Pitching Coach

No one has reported injuries or loss in velocity, and many of the responses started off with: “Well, I missed a few weeks, but gained X MPH anyway!”

Driveline Weighted Baseball Set

Driveline Weighted Baseball Set

However, this blog post is about a special case study that warrants further explanation. Daniel Gacke responded to my initial request for feedback with this email on September 4th:

I am in the final week of phase 1, and my longest throw for long toss has increased by at least 30 feet, depending on the wind.  Throwing the over and under weight balls is fun, and has helped, but I feel the biggest factor in my distance increase has been improved rotational mechanics of my left hip (I am a righty thrower).

On October 11th, Daniel followed up with this email:

Anyhow, when I was healthy and in college, I sat in the 82-85 mph range, and the fastest I ever threw was 88 once.  Since my surgery, the fastest I’ve thrown was 82 until today.  I just got done throwing a 6 oz baseball 90 mph!  I would have thought it was a fluke, except that I also threw it 89 twice and 88 once.  Now for the interesting stuff.  My best throw with a 3 oz ball was 87, with a 4 oz ball was 86, and with a 5 oz also 86.  In addition, the first few throws I made for the Jugs were with the 5 oz, and I couldn’t top 79.  I was afraid at that point that all my hard work was wasted.  Then I picked up the 6 oz ball and threw, and the guy with the gun told me it was 86.  At first I thought it was wrong, but the next was 85, and the next was 89.  Then after throwing that ball, I went back to the 5 oz, and was consistently 82-84, with an 86.  Then after throwin the 4 oz and 3 oz afew times, Iwent back to the 6 oz, and hit 90 once.

He went on to say:

I’m wondering if the heavier weight is causing me to innately choose a more efficient movement pattern when I throw.  Throughout working on your program, I always thought it just felt better when I threw the heavier balls, particularly the 6 oz, and the results showed that.

This is a fairly common sentiment. Personally, of all the baseballs, I really like throwing the 6 oz. baseball (though I do not throw it as hard as a regulation 5 oz. baseball) and hate throwing the 3 oz. baseball. Most of the athletes in our MaxVelo Program feel the same way. Daniel was even able to throw a 6 oz. baseball at 90 MPH – yet could not do this with a regulation baseball!

Daniel’s case, while not uncommon, has some interesting elements to it. As a former college pitcher with a long history of injuries (SLAP tears, frayed supraspinatus, bone spurs, etc), it can feel like you cannot tap into all your velocity. There are two major factors working against him:

  1. Ingrained motor patterns
  2. Psychological inhibition

Ingrained Motor Patterns

Very fine motor control develops over a long period of time when your brain has the strongest ability to acquire new skills. It’s why relearning how to walk is incredibly frustrating for those who suffer brain damage and is related to why it’s so hard to change your pitching mechanics once you reach the late high school level. A pitcher who has a long history of pitching with near-elite fastball velocities (upper 80’s) is going to have a predisposed way of throwing a baseball, and changing that pattern is going to be incredibly difficult.

When Daniel was in the high 70’s with a regulation baseball, I have no doubt he was reverting back to primary programming, which ultimately limited his velocity. He then picked up a foreign implement, threw it a few times, and then picked up a regulation baseball with that motor pattern imprinted in his brain – after which he was able to throw the ball 88-89 MPH! This is actually not a very common occurrence in most athletes; research suggests that this phenomenon is not widespread and is highly individualized (DeRenne, Blitzblau, et al). However, for athletes with a long history of slightly inefficient motor patterns, short-term “arm therapy” may prove to work.

Psychological Inhibition – A Contributor to Down-Regulated Intent

Daniel’s history of debilitating shoulder injuries, surgeries, and long periods of rehabilitation have psychologically scarred him – regardless of whether or not he is conscious of it. This is the biggest hurdle for most post-op pitchers who had major reconstructive surgery (Tommy John, labrum anchors, rotator cuff reattachment, even cuff debridement) – the physical part of rehab generally goes well, and mentally they are able to compete, but psychologically they know that throwing a baseball is what injured them in the first place, so the brain puts on the brakes.

Getting over this hump is not easy. Throwing at elite velocities (90+ MPH) requires massive intent to throw the ball hard, and anything that limits this will cause a degradation in performance. Using variably weighted implements to improve arm action, timing, and the physiology of the arm (bone cortex hardening, thickening of tendons, increased overall external rotation, and increased strength in posterior shoulder muscles) may very well grant psychological benefits.

So how does he throw a heavier weighted baseball harder?

Our hypothesis is that pitchers are able to throw a slightly heavier baseball as hard (or harder) than a regulation baseball because of increased intent in the delivery. They know that the ball is heavier, so they tap into a reserve of intent to try to throw it harder – it’s basically as simple as that. While a heavier baseball does invoke a physiological stimulus and this stimulus is partially responsible for increased fastball velocity, a major part is the organic improvement to the throwing mechanics of the pitcher. The pitcher learns to throw a baseball more efficiently and with more intent with the heavier baseballs and learns to not “push” the baseball with the lighter ones.

A break in the kinetic chain where the hand leads the elbow into the driveline will be immediately felt with a 3 oz. baseball (hence why most people hate the lighter ball – this is the most common flaw in pitchers) while a lack of intent will cause a 6 or 7 oz. baseball to wildly miss the target inside.

Light Baseball

I hate throwing this thing


Overall, Daniel had this to say:

 I know you are on the cutting edge as far as researching the act of throwing, and I wondered if you had any insight on the reason for me throwing the 6 oz ball harder than the 5 oz.  If nothing else, you can take this as a ringing endorsement of you program.  If you do have any ideas, I would really love to hear them.

Well, Dan, I hope this helps. And thanks for the kind words!

For everyone else: Our free ebook on weighted baseball training is a great way to get started training with weighted baseballs!



Have you ever thought the increase in velo on a heavier ball is just due to it’s increased mass? If, acceleration = force/mass, then the body needs to produce more force to move that mass, and the small gain in mass (1oz), while not enough to hurt or drop acceleration, is also likely enough to keep velocity maintained against external forces (air resistance). While psych stuff and motor patterns are important, I don’t think they explain this concept well.

Chris McKenzie



The body does not “need” to produce more force to move that mass. It needs to produce more force to


Empirically speaking, I’ve tested over 50+ people, and after sufficient familiarity with the implements, maybe 1 or 2 have been similar to Daniel. It is exceedingly unlikely that a normal mechanical model of throwing an implement would allow for a heavier object to be consistently thrown faster than a lighter object of same size.


Thanks, Kyle. I’m not trying to argue at all, please believe me. So out of your 50+ guys, did all of them throw the 3oz ball faster than the 5oz ball?


Yes, they did.


Momentum and inertia, in this example, would only apply to forces attempting to slow the ball down. At best, your theory would apply only to fingertips that hang onto the ball past its peak velocity.

A slightly heavier ball could force its way out of the hand slightly sooner than a normally weighted ball. This would seem to indicate a grip strength issue in the 2-3 pitchers that exhibit this odd velocity bump.

Perhaps Kyle will do some kinematic experiments on these three with differently weight balls in their hands. Are they releasing the heavier balls earlier? What about the control group (the guys who throw the normal balls harder)?


I have plans on doing just that and presenting it at Wolforth’s Coaches Bootcamp!


Hi Trip,

I think (not sure…haven’t looked at this) that max ball acceleration is achieved just after it is released from the hand, and velocity will remain constant or decrease from here. One of the forces acting to slow the ball down (excluding gravity) would likely be air resistance.
Where is the point on the mass:velocity curve when you can’t throw a lighter ball faster than a heavier one? Such as with a closed-window wiffle ball.


The ball will not accelerate after it leaves the hand because there is nothing left to accelerate it. Peak ball *velocity occurs during release shortly after the grip loosens (ball leaves the thumb or whatever finger is holding it in the hand). The ball escapes the hand when its forward momentum “pulls” it away from the fingertips of the pitcher. At that point, wind resistance is the only resistance the ball encounters, but since the ball has already left the hand, it can’t affect release velocity.

Now, if you’re suggesting that wind resistance plays enough of a roll in this situation to affect the pitcher’s arm speed, then I think you’re dramatically overestimating its role.



I believe wind resistance does not impart it’s effect on the arm, but on the ball itself. Keep all conditions and external forces the same, including arm acceleration and radar gun placement; by the time a lighter ball (mass unknown, regarding mass:velocity continuum) reaches the electromagnetic waves of the radar gun, it has the potential to lose more velocity than a ball that carries greater mass.

Also, empirically speaking, only a very very small percentage of players/pitchers have the necessary strength and power in the posterior cuff that allow the body to fully impart all of it’s force. The posterior cuff needs to have great eccentric strength/power. If not, the posterior cuff gets “turned off” (via the golgi tendon organ) because too much tension is going through it and the glenohumeral joint becomes unstable, decreasing arm acceleration. To avoid this, most players needs to be specifically trained. Only a few have true natural eccentric strength. I’ll bet this is another factor why only a few players can reach max potential arm acceleration while throwing a heavier ball faster…not wind resistance.

Chris McKenzie


I’m not even sure what you’re trying to say. Your original comment that I was responding to stated, “Velocity would decrease… as the mass of the ball decreases because it would carry less momentum and inertia.” I have been trying to refute/understand that statement because at its face, it does not make sense to me.

If you’re talking about final velocity or average flight velocity or radar measurement error or whatever else, then that’s fine, but those are issues beyond the pitcher’s control (outside of how he spins the ball, obviously) and do not seem to have anything to do with a pitcher’s force application techniques.

Daniel Gacke

I just read through the comments here, and thought I’d throw my personal experience into the mix. I’m not sure I understand Chris’s theory, but one thing that I can say for sure is that, from my perspective, the amount of effort and force that I was putting into the early 78-79 mph throws with the regulation 5 oz ball was exactly the same as what I was putting into the 88-90 mph throws with the 6 oz ball, the 87 mph with the 3 oz ball, and the 84-86 mph throws with the 5 oz ball after throwing the weighted balls. All of them were flat out, “pedal to the floor” for me. I was grunting. To me, that was a sign that the issue is mechanical, or maybe as Kyle stated, unconsciously mental. As for grip strength being an issue, I can tell you for sure that static grip strength isn’t an issue for me. I grew up on a farm, and grip strength kind of comes with the territory there, because of the kind of work you do. I can spin the dial all the way back around to zero on one of those hydraulic grip dynamometers. Maybe it’s a different release point, or the grip strength expresses itself differently in a ballistic motion such as throwing. Whatever the answer is, I’m determined to figure out how to take 90 mph out to the mound with me. Either that or waterlog the baseballs before games, so I can throw them harder!

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