arm circle speed-univerasal constant

[FiveFrameSwing]

Until a few months ago, I had no clue about the forearm brushing the hip. I think it was a conversation bewteen Bill Hillhouse and Rich Balswick that got me thinking about it, then Rick stopped by and gave it a name. I was skeptical, however, started looking at video and pics of high level pitchers and realized it's been right there all the time.

I think if you start with good posture and elbow leading to the side, forearm brush will likely happen. The key word is "brush." If you're getting "bump" and some discomfort, check the posture. I'm not sure it's super critical to force brushing vs setting up the conditions that result in it. That's something Rick or Rich might better address.

The concept has been around for over a decade. Doug Gillis referred to it as "brush assisted whip" in his old VHS pitching videos.

Rick is showing recent data he's collected in which the arm accelerates from 9-oclock to 6-oclock ... but it isn't just 'acceleration' that is important, but also 'deceleration'.

 

[FiveFrameSwing]

Thought a little visual may help.
JJSqueeze noted a range of .33--.40 seconds on the girls he timed. In this video and posted above you will note that Sarah's arm circle is at .3903 seconds.....nearly the slowest relative to JJ's data....and yet she probably has one of the fastest ball speeds (game speeds of 67-70mph). So this may lend credibility to the idea that arm speed is not as important as many would believe.

JJ.....curious, do you have a ball speed estimate on the .33 second arm speed?

Any other thoughts on this??????

A few thoughts .....

You've spoken of resistance, and IMO resistance is a big key.

The notion that body parts reach a maximum velocity, and then decelerate in order to pass their momentum to the following segment, can be a difficult concept for many people to grasp. That said … that is the process that we are discussing ... ... ... i.e, accelerating and decelerating body parts.

As an example … you've spoken of how the front side is used to decelerate and transfer energy.

The greater the acceleration, or deceleration, the greater the force. Force = M x A. In other words, a rapid change in velocity results in significant force ... whip effect.

Think in terms of the “law of conservation of momentum”.

Momentum = M x V.

What the "law of conservation of momentum" states is that MV(before) = MV(after). If energy is transferred from a heavy segment to a lighter segment, then it stands to reason that velocity must be increased by a corresponding amount ... since MV(before) = MV(after).

Rapid deceleration of the upper arm is important because it results in maximum momentum transfer. Since energy is being transferred to a lighter segment, and since momentum in conserved … i.e., MV(before) = MV(after)… then it stands to reason that if the Mass of the segment is reduced, then the Velocity will increase correspondingly by the reduction of Mass. Doing this quickly, in terms of rapid deceleration, results in greater force production.

 

[FiveFrameSwing]

Note that Force = Mass x Acceleration …. and not Mass x Velocity.

Acceleration and Velocity are different … albeit related.

Acceleration is the “rate of change” of Velocity as a function of Time … Acceleration = change_Velocity / change_Time.

To the extent that it is physically possible to consistently undergo a greater change in velocity, albeit at a somewhat slower maximum velocity, then it is possible to exert a greater force at a lower velocity.

In other words, the observation that someone with a slower arm speed can throw faster is quite believable.

Greater arm speed does not necessarily mean greater force application.

Mechanics do matter.

 

[sluggers]

A discussion of "arm speed" without defining "arm speed" is pointless.


1) What is "arm speed"? For pitching, the arm has four parts: The upper arm, the forearm, the wrist and the fingers. So, when you say, "arm speed", what part of the arm are you talking about? Are you talking "arm speed" in RPS, or in FPS? If it is FPS, which part of the arm are you talking about? The fingers have higher linear speed than the wrist, which has a higher speed than the elbow, which has a higher linear speed that the shoulder.

2) If you are talking RPS, which axis are you talking about? There are three primary axes of rotation for the arm...one axis is the shoulder and one is at the elbow. The other axis is parallel to and between the radius and ulna of the forearm (the IR axis).

3) The speed of a thrown ball immediately after release is equal to the speed of the fingers. That is, the ball doesn't magically increase speed after release.

4) The lower body is important...but, about 80% of the speed comes from the arm. Have a girl get open and throw without using her lower body. My DD threw around 50 to 55 MPH without using her lower body.

5) There are three basic ways to describe motion: momentum and force/acceleration. Momentum works well when you have an object in motion interacting with another object. (e.g., pool balls) If an object is accelerated by a force internal to the object, then force/acceleration equations are better. When you look at pitching, it is best to use both.

For pitching, there is a momentum transfer from the lower body to the arm, so the best way to think of it is as a momentum transfer. But, once you get to the arm, the best way to think of it using linked levers because the arm muscles are accelerating the ball.

6) The whip isn't magic. It is simply the result of a linked lever. A linker lever is a series of rods connected at their ends. The best example of a linked lever is the drive for a steam locomotive. To work efficiently, a linked lever has to be well timed (hence the need for things such as timing belts). The arm muscles (the "arm" meaning the whole arm) have to contract in a particular sequence in order to achieve maximum linear velocity of the fingers at release.

Mechanics do matter.

Wow...who would have thought?

 

[starsnuffer]

To further complicate matters, it's a lot more then simply transferring energy. The timing of when to transfer in order to maximize the benefit of gravity and to maximize speed at release is just as important. Most pitchers, especially those with an exaggerated backswing, are not far enough along in their arm circle to maximize the transfer that takes place at foot/heel plant along with gravity so they end up expending extra energy to achieve the same effect as a pitcher who does have a more efficient sequence, resulting in less ball speed then they would otherwise be capable of.

I guess what I'm saying is that it isn't just how, but when.

-W

 

[FiveFrameSwing]

A discussion of "arm speed" without defining "arm speed" is pointless.

I thought Rick was pretty clear in the video he presented.

At 3-o'clock the reference was the "ball".

At 12-o'clock the reference was the "ball".

At 9-o'clock the reference was the "ball".

At 6-o'clock the reference was the "ball".

He was looking at the speed at which the "ball" was being moved within the pitching motion.

It shouldn't surprise anyone that the quadrant with the 'whip' had the shortest time segment.

 

[sluggers]

He was looking at the speed at which the "ball" was being moved within the pitching motion.

OK...but "ball speed" is not arm speed, is it?

I appreciate Rick's careful analysis of the pitching motion and his very good instruction on teaching pitching. I'm not "dissing" any of that. But, with respect to this, he is reinventing the wheel.

That is:

At 12, the ball and the upper arm are at the same angular position with respect to the shoulder. At release, the ball and the upper arm are at the same angular position with respect to the shoulder.

At 9, the ball is lagging the upper arm. Since the ball is lagging the upper arm, it's angular velocity must have been slower than that of the upper arm.

At release, the ball has "caught up" and now is at the same angular position as the upper arm. Therefore, the ball must have been moving faster than the forearm from 9 to release.

Here is a simple diagram about the arm movement mechanics. The black portion is the forearm. The mauve portion is the upper arm.

The instantaneous linear speed of the ball is:

ball velocity = (angular velocity of upper arm relative to the shoulder)*(length of upper arm) + (angular velocity of lower arm relative to the elbow)*(length of forearm).

This equation explains why "the whip" produces faster ball speed. If there is no whip, the angular velocity of the forearm relative to the elbow is zero. So, the speed of the ball is equal to the angular velocity of the forearm * the length of the arm.

If there is a whip, then the angular velocity of the forearm relative to the elbow is actually negative from 12 to 9, resulting in the ball moving counterclockwise relative to the elbow.

From 9 to release, the angular velocity of the forearm relative to the elbow becomes greater than the angular velocity of upper arm.

If the timing is correct, the angular velocity of the forearm relative to the elbow is greatest at release, meaning that the speed of the ball at release is greater. Actually, it is a pretty nifty trick.

What Rick should be measuring is the time it takes the elbow to go from 12 to 6. With that plus the length of Sarah's upper arm and forearm, it is pretty easy to calculate the angular velocity of the forearm relative to the elbow. (Can you get me the length of her forearm [elbow to tip of fingers] and upper arm [shoulder to elbow]? That would get us an approximation of the angular velocity of the forearm. Maybe there is a way to measure the angular velocity of her forearm relative to the elbow...if so, then we could also calculate how much speed is added by IR.)

If you look at the equations and think about pitching, it is pretty easy to see why "the whip" is so important. Pitchers can generate more speed with less exertion by any one muscle.

The downside of "the whip" is that the timing is difficult. The pitcher has to learn exactly when to fire the triceps and start accelerating the ball.

 

[Rick Pauly]

SS has provided two great descriptions-----"its a brush,not a hit" and "the arm "rolls".
Here is one thing that I fear though.....I have had way to many pitchers of a wide variety of ages (12----18) come to me and they have zero brush interference with their lower arm and hip/thigh. In almost every case their control and ball movement are poor. I can tell you from my experience that it is not an easy fix to convert them into "brush interference"........very easily a 12 month process if the pitcher is diligent in her practices....may never happen for some, especially if they have pitched for some time not getting brush interference. If someone has a great trick to speed up the conversion I would love to hear it.
I concur that young pitchers probably lack the core stability needed not only for good resistance but for the ballistics of pitching in general. SS, in your experience when do you typically see young ladies having developed enough core stability to attempt brush interference? I don't work with many 7-10 year old kids so maybe those are the pitchers being referenced.

It's a brush, not a hit, and the important thing is that the arm "rolls" over the front of the abdomen (generally between the belly button and hip) spreading out the contact.

That said, this is generally not a taught action, it is an action that happens as a result of good mechanics. Teaching this motion is dangerous, especially to kids who have not developed yet (yes, OILF, I'm saying it again). Younger kids not only lack the core strength to open and resist with their hips properly, but their hip size and width is changing and what may be a brush today will be a hit tomorrow.

We don't teach baseball pitchers to bend their wrist back behind their head and press their elbow towards the sky as they pitch, but that happens anyway as well.

-W

 

[starsnuffer]

It's a tough subject, Rick. There isn't really one good answer, as each kid is different and grows at different times. Here's my thoughts and what I use:

If you have the kid stand facing away from you in their natural posture, before puberty their arms will hang down to their sides pretty parallel to their body, depending on their body shape. At some point as and after their hips develop the elbow will become the closest part to their body and their forearms will turn out slightly away from their body. Their arms aren't changing but they are learning to externally rotate them to make room for their hips. It is at this point that their bodies have become subconsciously aware that their hips are in the way of their arms and you can start to have them brush. Teaching this before this point is going to be difficult and a waste of time because you are trying to teach them something that their body hasn't figured out on its own yet, and the concept is alien at this point.

Where and how the brush happens is again dependent on body type. Taller people have disproportionately longer humorous and femur bones. Torso length does not vary as much between short and tall people as these bone lengths do, meaning that the elbow is in a different altitude in relationship to the hip for different height people. Musculature and posture also play a role in how high or low the shoulder is which also changes the altitude of the elbow. We spend a lot of time working on shoulder relaxation, function, and movement in order to lengthen the working lever, so how much of this instruction the student executes also plays a factor. In addition to arm length and elbow height, you also have the abdomen to consider. A fit or slim student will be able to brush across the front of the hip but a pitcher with a belly will brush higher along their belly.

I think a good starting place would be to demonstrate with BM's lock it in drill. While this isn't brush interference, it demonstrates how the upper arm remains still yet the arm whip still happens. Students are able to release accurately and consistently from this drill in comparison to other static body drills. I've also had success showing video of pitchers and pointing out how their upper arm stops or pauses to initiate the lower arm whip. For some students, simply being aware helps them. Telling a student of a thing usually does not make them aware, they really have to see it.

I hope this rambling helps.

As for the 7-10 year olds, they're generally all over the place for many reasons, lack of brush interference is one of them, but there are plenty of other areas of focus to keep them busy while they develop their cores. Luckily at this age, throwing the ball with good velocity "somewhere" in the strike zone generally equates success.


-W

 

[goosesdad1]

I agree, with fiveframe, mechanics do matter.

It's like an elephant kicking a ball: the leg doesn't move real fast, not like a football kicker, but there is a ton of energy supplied because of the mass. So, yes, someone with a slower arm speed could throw faster. But, I think most of the time in pitching, a faster arm speed results in a faster pitch.

Keeping with the classical mechanics, I've been trying to think of the pitcher as a trebuchet on rails. I imagine the whole trebuchet on a rail car that is propelled on a short length of track where the car is quickly accelerated and then decelerated. The trebuchet is the upper body and the rail car is the lower body. So, to maximize velocity, what the pitcher is trying to do is add the momentum generated by the push to the trebuchet whip action of the hand and finally the fingers and ball.

Obviously, for maximum energy transfer, timing is key. But also important is keeping the rails well greased. That is why I believe the limiting factor of speed is the transfer of energy from the back side into the front side, not arm speed. We've all seen this with a kid's arm going a 100 mph, all bent over and the back leg hanging back, not usually a lot of resultant ball speed, although the effort produced is always desired and greatly appreciated nonetheless.

The quicker the pitcher can transfer the energy of momentum into the whip, the faster the pitch will be. This is greasing the rails. I believe this to be true of hitting also, not the trebuchet analogy, but the quicker the energy is transferred to the front side in time with the whipping action of the hands and barrel, the more force will be transferred. Speed is one part of the equation, but I believe that ultimately, focus on conservation of momentum first before trying to increase arm speed results in arm speed anyway because the whip has to keep up with lower body.

I need to find better ways to get them to get transfer the energy of the push and get that backside through quickly and efficiently - without interfering with the whip coming through.