Study Proves Arm Strength Is Not A Factor In Pitching Velocity

by Dick Mills on July 21, 2009

Most coaches today believe that arm strength is an important factor for producing more pitching velocity. This is why most coaches advise that pitchers use long toss or weight training as overall conditioning tools to increase pitching velocity.

However, science has disproved this belief that pitching velocity is related mostly to arm or shoulder muscle strength.

The facts actually prove that pitching velocity is created before the arm starts to move into acceleration. During arm acceleration from the cocked position at landing all the way to ball release there is very little muscle activity going on in the pitcher's shoulder. (See Attached Photo: In the attached photo of Josh Beckett,  in the cocked position at landing, his body has stored all the elastic energy from his stride and his arm cocking action...which will whip his arm through at the last moment. His pitching velocity has already been produced at this point.)   

Coaches should read and understand this important study

Jobe, Tibone, Perry and Moynes (1983) analyzed EMG (muscle activity) in the shoulder muscles in pitching. Getting to the cocked position showed considerable muscle activation: deltoid, the SIT muscles (scapularis, infraspinatis, teres minor and then the subscapularis - (all rotator cuff muscles)). However, acceleration out of the cocked position exhibited virtually no muscle activation. Only after the ball was released and the arm and shoulder needed to slow rapidly in the follow through were there any high levels of muscle activity.

The velocity of a pitch is affected by the elastic properties of the arm (residing mainly in the ligaments, tendons and isometrically contacted muscles) and not by muscular contraction (which would occur from arm strength).

Most baseball coaches find this very hard to accept that muscular strength is not a factor for improving pitching velocity.  However it is supported by evidence and contradicts common coaching beliefs.

So what does this mean and why should all pitchers understand this.  This means that pitching velocity is created by putting as many muscles of the body into a fully stretched position quickly as the pitcher moves from the rubber into landing. This is why moving fast and explosively away from the rubber into a long stride is important for producing more velocity.  Thus why the body produces velocity...not the arm.

Basically at landing, the elastic properties of the muscles and supporting ligaments and tendons store this elastic energy which is how the arm is whipped through at high speed.  Muscle strength has little to do with it.  

Thus why doing long toss or weight training is not a good investment of time for pitchers.  Focusing on moving more explosively into a long stride will have the biggest affect on improving pitching velocity. Improving explosive mechanics is the key to more velocity.

This is what I have been focusing on in our Explosively Pitching DVD program since 2004.  We teach parents how to help their sons use their bodies to pitch instead of just their arms. Not only does this improve velocity but reduces the risk of arm injuries. http://www.pitching.com/products/

"My 14 year old son's velocity jumped 12 mph, his control improved dramatically and his arm pain vanished. For the first time since he has been pitching, he finally understands what he is doing...what causes the ball to do what it does and how his body functions to be effective...now that is priceless." 

Mark A Smith, Downers, Grove, IL