With the offseason in full swing, many parents have asked me about their child using weighted balls to increase arm strength and velocity.  The use of weighted balls has been a highly debated topic in baseball for many years.  Some believe very strongly in them and others think they could be a one way path to Tommy John surgery.

I have always had conflicting views on using weighted balls with kids that I work with.  I have always thought that adding more weight to a movement that is already tremendously stressful on the body wasn’t a good idea.  However, there are many anecdotal reports that claim they have tremendous benefits.  So, playing it on the safe side, I never used them basically out of a lack of information out there regarding their efficacy.

I recently attended a seminar where Mike Reinold spoke.  Mike is the former physical therapist for the Boston Red Sox.  He is one of the most respected shoulder experts in the world and one of the smartest people I have ever met. I was able to pull him aside and ask him his thoughts on using weighted balls.  So, much of my thinking comes from what we spoke about.

 The first thing to understand is that using weighted baseballs work.  They will help most pitchers develop velocity.  How?  The added weight of the baseballs will add more external rotation to the shoulder as we get to the lay back phase.


The more external rotation that we have, the harder we will throw.


Sounds great right?


Well, adding more external rotation to the throwing motion may not be the best thing for the health of our shoulder.  The vast majority of baseball players have an acquired adaptation called humeral retroversion, which is a fancy term for our bones being shaped in a way that allows the shoulder to gain more external rotation.

However, while we need to get to these extremes to throw hard, more is not always better.  The more external rotation we have, the better chance of injury.  Three major injury mechanisms come out of having too much external rotation.  The first is that the head of the humerus (upper arm bone) drifts forward the more that the shoulder externally rotates.  This loosens the ligaments in the front of the shoulder.  This can lead to shoulder instability and a better chance of injury.


The second injury mechanism that occurs when we have too much external rotation is increased valgus stress on the elbow. The more valgus stress that is placed on the elbow, the more stress is placed on the ulnar collateral ligament or Tommy John Ligament.

The final injury mechanism is an increased incidence of rotator cuff injury.  Baseball players are more susceptible to internal rotator cuff impingement.  This injury is often seen in pitchers due to the crazy amounts of external rotation that occurs in the lay back position.

What about under weight balls?


Most weighted ball programs include the use of baseballs that weigh less than 5 ounces.  The reasoning behind this is to teach the arm to accelerate faster through the pitching motion.  Although weighted ball programs tend to do better with the use of underweight balls, there are injury concerns with these as well.


Throwing a baseball is one of the fastest motions in all of sports.  The humerus internally rotates at over 7,000 degrees per second during the acceleration phase of throwing.  This places tremendous amounts of stress on the external rotator cuff muscles to help decelerate the arm.  Using a baseball that weighs even less, means even faster accelaration forces, and even more stress placed on the deceleration muscles.  Mike asked me if I had ever thrown a tennis ball as hard as I could and asked how my arm felt after.  I have and can remember my arm being sore for days.

So, are weighted balls bad?

Not necessarily.  It really depends on who we are talking about.  If we are talking about a 27 year old pitcher sitting in double A who is on the verge of getting released, or a college pitcher who needs to gain 5 mph to their fastball to play at the next level, then weighted balls may be the answer.  If we have exhausted all other options, weighted balls can be an effective way to increase velocity.  However,  if we are talking about a 9 year old who wants to throw harder, using weighted baseballs is probably not the best idea.  There is so much maturity that can still take place, and many more ways to help younger players increase velocity in a much safer way.