Arm whip

[starman]

I think I have a decent handle on most of the mechanics. But, I feel like I don't really understand the release on the fastball.

The best way to get a feel for it is to watch it in slow motion and then try it yourself. The upper arm traps against the ribcage and rotates internally. This causes the forearm and hand to start pronating, so that the fingers are behind the ball at release and the hand continues pronating into a palm down position after release.

The pronation after release is a natural consequence of the internal rotation of the upper arm and the transfer of those forces down through the forearm, not a forced mechanic. Trying to finish any other way doesn't really work unless you don't internally rotate or try to stop your internal rotation halfway through, so that your hand doesn't turn over. I don't think either of those are really what we are looking for.

 

[SETPRO]

As stated in a previous post from my perspective in order to understand what IR is and have a better chance of teaching it need to understand the how the body creates the IR movement. And then at little bit of math and physics.

I put together a quick overview of what I think are important IR anatomical movements and their terminology.

"Enjoy!"

 

[Steggy111]

What does it mean for you,

1) How is it created?

and

2) how would you explain it to a student?

By using this:

 

[SETPRO]

If one is serious about studying movement high-speed video is an absolute necessity. As I said previously said I've done quite a bit with overhand pitching and when the great benefits is there are a number of high-speed video clips of high-level pitchers on YouTube. The benefit of high-speed video is it allows much better observation of exactly what is happening with body parts with respect to time.

I've searched YouTube for high-speed video of fastpitch pitchers and today have only come up with one reasonably good video:



And even this video is not very good because according to the video information it has a frame rate of 1000 fps is posted on YouTube at 24 fps (display frame rate) viewing. And after doing some measurements the entire clip does not represent 1000 fps. The initial wind up portion (approximately half of the video) is something much less than 1000 fps and the remaining portion from a analysis standpoint runs at approximately 500 fps.

That being said it's about the best I can find to do any reasonable discussion.

I took a portion of the video that was done at 1000 fps (displays at 24 fps) and did some plotting of elbow joint vs hand position during a portion of the delivery.

The green arrows represent the distance moved per unit of time of the center of the hand.

The yellow hours represent the distance moved per unit of time of the center of the elbow joint.

Unit of time at 24 fps is .33 seconds per plotted point.

My reason for making this plot is make sure everyone sees that the movement of the elbow slows prior to release of the softball. Whereas the distance traveled by the hand remains relatively constant from point-to-point.

Also the flex (angle between upper arm and forearm) remains relatively constant.

This was the initial observation i.e. elbow slows down, no change in forearm upper arm joint angle, as ball travels through final portion of delivery. Upper arm slowing down but no change in upper arm-forearm joint angle is not typical of a whip type action.

In the overhand throw as the forearm extends as upper arm rotation slows down i.e. upper on momentum is transferred to forearm.

What is happening in this delivery of the softball is the bent forearm is rotating around the long axis of the upper arm i.e. internal rotation (IR). This is what gives the appearance of the elbow coming to a stop well the hand continues to move along the path of the delivery.

Also this is not pronation of the forearm. If the forearm was pronating you would not see the hand continuing to move forwards. It would come basically to a standstill same as elbow.

 

[SETPRO]

I want to thank starman for referencing the paper (study?):

Peak Elbow Flexion Does Not Influence Peak Shoulder Distraction Force or Ball Velocity in NCAA Division I Softball Pitchers

High shoulder distraction force has been observed in softball pitchers during the acceleration phase (top of the pitch to ball release) of a pitch. Increasing elbow flexion may reduce shoulder forces and the susceptibility to pain by shortening the lever ...

www.ncbi.nlm.nih.gov

Over the years I've looked at many overhand pitching papers. My biggest questions (criticisms?) with trying to infer information/results that can be applied to any specific player are 1. Exactly what question(s) is/are the study trying to answer and 2. How was a study performed. It's been my experience the biggest variable in the studies involving players is/are the actual players themselves.

The purpose of this study:

To determine the association of peak elbow flexion during the acceleration phase of the pitch with peak shoulder distraction force and ball velocity.

This study was performed by using these methods:

A total of 61 female collegiate softball pitchers (mean age, 19.9 ± 1.9 years; mean height, 175.7 ± 5.7 cm; mean weight, 83.6 ± 12.7 kg; 49 right-handed) volunteered for this study. Biomechanical data were collected with a 3-dimensional electromagnetic tracking system while the pitchers threw 3 maximal-effort fastballs at a regulation distance. Peak elbow flexion and peak shoulder distraction force were calculated for the acceleration phase and averaged across the 3 trials. Ball velocity was assessed with a radar gun.

Study Conclusion:

Peak elbow flexion did not influence ball velocity or peak shoulder distraction force during the acceleration phase of a windmill softball pitch. However, there was a significant and positive relationship between ball velocity and peak shoulder distraction force. These results may indicate that ball velocity and other kinematic variables may be more related to shoulder distraction force than elbow flexion.

Based on this study one might conclude that elbow flexion has nothing to do with velocity. Yet based on much of the discussion on these forms a bent elbow i.e. "elbow flexion" can increase velocity primary through the application of IR.

So how does one reconcile study versus discussions (results) in these forums?

 

[ArmWhip]

It's often difficult to extrapolate useful information from studies such as this, if they had an instructor as an advisor it might be different. The first thing that jumped out to me was that mean velocity was 55 mph +-3 mph, that's slower than I would expect.

Without knowing where peak elbow flexion occurred the data is useless, most of my pitchers have more elbow bend when they are at the 12 o'clock position than they have at release.

The peak shoulder distraction figure might be useful, but I'm not sure exactly how and where it is determined, and correlation does not mean causation. If shoulder distraction is significantly affected by the centrifugal force generated by the arm circle then it would make sense for it to be correlated to velocity.

This study led me to another one which concluded this:

"Results revealed that those pitchers who had greater trunk (SE = 0.018, t = -2.5, p = 0.023) and elbow flexion (SE = 0.006, t = -4.2, p = 0.001) at the event of foot contact had lower ERAs. This study supported previous research on the importance of trunk and elbow angle at front foot contact on rise ball pitch performance."

But since it was for rise balls the info might be pitch specific.

 

[Hillhouse]

Wow, and I mean WOW.

I wanna preface this by admitting upfront that I am not very smart. I made it through high school but never went to college. I don't know how many of you all reading this could follow along with the above posts but, I could not. And it's unfortunate because there might be some terrific information in there that I just can't understand. I truly hope others could follow along. And while I'm usually very sarcastic, and try to use humor often, I'm not trying to be funny here. Trying to read that for me was like trying to read ancient Egyptian hieroglyphics.

Honest questions, how do you dumb down all of that information for someone who couldn't follow along?

 

[SETPRO]

Honest questions, how do you dumb down all of that information for someone who couldn't follow along?

Part of the problem with the "information" in this discussion of "Arm whip" is mixing in other topics such as the value of "studies" in the information the present.

As I tried to explain in my first post here I was very interested in trying to better understand the fastpitch throwing (pitching) process. It was particularly interesting because it was so very different than overhand pitching (throwing) which I have spent too much time trying to understand.

Also I tried to simplify my approach saying that there were three components:

1. Physical/anatomical component i.e. how the body moves, specifically arm action.

2. A math component which I have not really pointed out yet and is related to the physics component.

3. A physics component which I am still trying to more fully understand.

Previously represented what I hoped would be a reasonably well documented overview of how the arm moves which is fundamental to establishing a basis for discussion of arm action during the fastpitch process.

Searching the interweb for "fastpitch internal rotation" I found what I consider an "interesting" description with respect to fastpitch IR throwing:

“It has been shown that internal (medial) rotation around the long axis of the humerus is the largest contributor to projectile velocity. This rotation, which occurs in a few milliseconds and can exceed 9,000°/sec , is the fastest motion the human body produces.“

Why Internal Rotation Produces Better Fastpitch Pitching Results

The other day I came across a great post on the Key Fundamentals blog titled Softball Pitching Myths Pt. 2 – Hello Elbow by Keeley Byrnes. Keeley is a former pitcher and now a pitching coach …

fastpitchlane.softballsuccess.com

Interestingly (for me)

This article also references a paper that I'm extremely familiar with and I've quoted many times with respect to the overhand throwing process:

Elastic energy storage in the shoulder and the evolution of high-speed throwing in Homo

Elastic energy storage in the shoulder and the evolution of high-speed throwing in Homo

Although some primates, including chimpanzees, throw objects occasionally[,] , only humans regularly throw projectiles with high speed and great accuracy. Darwin noted that humans’ unique throwing abilities, made possible when bipedalism emancipated ...

www.ncbi.nlm.nih.gov

I was hoping as this discussion progressed to be able to create a reasonably understandable rationale for the IR process.

The problem is I don't know how to do this without introducing some complexity but in so doing try to make it as understandable as possible. As I said I think some of the discussion has strayed a little bit with respect to studies but the reason for the inclusion is they did make certain statements that could be construed as either supporting or not supporting IR (bent arm).

I think it's best not to invoke any additional studies unless they are very very specific to the IR process.

I still have more I would like to present for contemplation.

For example a simple calculation using internal rotation rate of the hu and 9000° per second with a bent elbow creating approximately a 12 inch radius to be transcribed by the elbow-hand/ball projection equates to ball release speed of over hundred miles per hour.

Another assumption is that the final release velocity of the ball at the end of the IR arm swing had to be greater than the velocity of the arm-ball swing going into IR. That the IR velocity is additive to the arm swing velocity going into IR.

I would hope that at the end of this discussion it will be possible to "dumb down" the results into something

 

[ArmWhip]

Honest questions, how do you dumb down all of that information for someone who couldn't follow along?

Ha ha, that's why I led off my post with this statement.

It's often difficult to extrapolate useful information from studies such as this, if they had an instructor as an advisor it might be different.

When I read these types of studies I have skip over a lot of the statistics and just read the conclusions. The math makes my head hurt.

 

[SETPRO]

When I read these types of studies I have skip over a lot of the statistics and just read the conclusions

Conclusions are based on specifics of/to the study. The study premise and study methodology are important and often cannot be ascertained from the conclusion.