Arm Action

I’m interested in hearing some thoughts and suggestions on proper throwing arm action. I’ve heard tips such as circular motion (aka making snow angels), later hand break (after forward momentum), and showing the ball to 1B/3B when talking about it, but I was interested in a more detailed discussion.

Any thoughts are eagerly anticipated!

It doesn’t seem to matter what you do with the ball after breaking the hands - As long as it is cocked (at approx. 90deg) when footplant occurs. The arm’s path after that would be the result of many other contributors.

Also, it seems most people are recommending a righty show to the SS.

There are many people on here that will provide much better (succinct) explanations though. Or even correct ones…

very complicated topic. Most important thing is that the arm action is connected to the rest of the delivery, allows proper scap loading and external rotation to occur.

People say have a loose, or smooth arm action…I’ve seen loose and smooth but terrible arm actions…the fundamental movement pattern is what is important, it can be smoothed out later. If, during a 50% intensity light throw you aren’t achieving excellent hip shoulder separation (hips fully open at landing, shoulders fully closed, ball in high cocked scap loaded position) there is something fundamentally wrong with your movement patterns. Crawl before you walk, walk before you run.

For example, I spent many hours trying to figure out how pitchers like randy johnson were able to get their throwing arms in such amazing scap loaded positions while keeping connection and smoothness. I realized it has less to do with flexibility, or strength, and more to do with the actual way the hands are broken, angle of the hand/forearm and the actual path the arm takes to get into position to throw. And it’s not as simple as saying “just break the hands with the elbows” because there are plenty of wrong ways to break the hands with the elbows and end up with a low level arm action.

Paul Nyman has some really good stuff on this. This begins to touch on it

Backchaining is the best way to understand this phenomenon, as you alluded to in your post, LL. The “feeling” of the forearm gaining momentum is something that can’t be taught using markers or stages.


Good stuff!

Other guys can confirm this, but I seem to have found a common trend with pitchers arm action.

I noticed that as the elbow goes from power position and forward, the elbow seems to rise. And for pitchers who have a lower arm slot, like Randy, the elbow elevation is less.

This seems to me like it would lead to more external rotation.

I may be way off base, but it seems to be a trend of some sorts.

Observations and opinions regarding arm action.

When talking about arm action you’re talking about five components:

  1. Shoulder complex i.e. scapula.
    2.Upper arm/humerous.

You are also talking about three results of arm action:


Discussions regarding arm action very rarely if ever take into account all of the above.

Some additional questions/thoughts regarding arm action.

Why does one pitcher throw 95 mph with no movement and another pitcher throw 95 mph with great movement?

Why was it that Billy Wagner at 5’10" and Randy Johnson had 6’10" both threw with the same velocity?

How come so many pitchers who are 6’5" tall and weigh 230 pounds throw no faster than their 6 foot 180 pound counterparts?

Swinging a bat and throwing a baseball arm biomechanically identical.

Biomechanical simulations indicated as possible to throw 95 mph with no active muscle activity other than iso-metric actions (holding and then releasing), i.e., no active contractile activity as defined by muscle shortening actions.

The following is only for those who have nothing better to do with their lives other than to try and understand how the body actually throws the baseball.

[quote]Theory One (Ford, 1998) states that once the motion of the system begins, an angular momentum is developed in the system and the distal segment lags behind. As the proximal segment approaches maximum velocity, an external force opposes this motion, which negatively accelerates the proximal segment, allowing inertia to propel the distal segment forward. Kreighbaum and Barthels explained that as a result of the negative acceleration of the proximal segment, the axis of rotation for the more proximal segment shifts from the proximal end to the distal portion, decreasing the radius of gyration, thus decreasing the rotational inertial for the more distal segments (Kreighbaum & Barthels,1985).

This theory is the more widely accepted of the two theories and has been studied in various movements (e.g. throwing, kicking, striking). The most common analysis of Theory One is the overhand baseball throw. In a study simulating the overhand throw, Herring concluded that a series of events including: (1) proximal-to-distal sequence of the onset of joint moments, (2) simultaneous peaking of segment velocities at the instant of the preceding segments minimal velocity and (3) reversing moments, created an inertial influence on the acceleration of the distal segment (Herring & Chapman, 1992). Another study that supported Theory One utilized a model to fractionate the three dimensional angular acceleration vector of the segments during an overhand throw into the two-dimensional kinetic and kinematic parameters (Feltner, 1989).

The results of this computer model revealed that the elbow extensor muscles created no extension moment as the distal segment began its rapid extension, suggesting that the inertial component of this joint action was the responsible agent for elbow extension. While Feltner was the first to propose that the elbow extensors did not contribute substantially to elbow extension during the overhand throw, it was not until Dobbins (Roberts, 1971) who, through the use of a differential radial nerve block to eliminate triceps activity, was able to provide substantive proof. Dobbins reported that after six practice trials, the participants were able to throw at greater than 85% of the velocity attained before the nerve block. These findings give credence to Feltner’s suggestion of the relative lack of contribution of the elbow extensor muscles during the rapid elbow extension during the overhand throw. The notion that the elbow extensors sparsely contribute to elbow extension in the overhand throw was further supported by two other groups, who reported very little elbow extensor activity during the rapid elbow extension using EMG analysis (Toyoshima et al., 1976; Atwater, 1979; Fleisig et al., 1995), each supporting the inertial based Theory One (Ford, 1998)[/quote]

this is fantastic stuff, paul. Do you have any other studies that look at the activation of various muscles during certain phases of the throw? For example pec major or latissimus dorsi? I remember reading a study that found high level throwers activated their lats 300% more than lower level throwers.

This stuff seems very relevant to where emphasis is placed in a pitcher’s strength training program. If the elbow extensors don’t play an active role in the throw, this seems like another blow to the whole bench pressing for pitchers debate. Anecdotally I feel like the lats play the biggest active role, but I would love to see more research like this.

thanks Paul

By the way, Feltner (and Dapena, the person responsible for the creation of motion capture labs) is hugely influential when it comes to understanding the biomechanics of pitching. Look up his other work for more information.

for those who are interested in Paul’s source. Great stuff so far, I’m still working on it.