Arm speed

Out in Left Field said:

No, I am talking about the graph that displays the average contribution of the elbow to ball speed is 4%.

Click to expand...

Right. And though it doesn't specifically say in the pitch speed section, if you go back to the injury section it is talking about elbow angle. I think (but cannot state to 100% certainty) that the 4% is referring to the angle of the elbow, mainly because that is the only measurable stat mentioned. The images on page 10 show the elbow angle circled, as well.

This is a common question... and as some have asked or stated recently that they wish to know more about the 'science', I'll try and make this readable. But first...

Out in Left Field said:

Could we discuss why so much time is spent on the last 1/4 of the circle when it only contributes 4 (5)%?

Click to expand...

This is a misrepresentation of the data provided in that report. The last 1/4 of the circle comprises much more than a single articulation at the elbow. Interpreting the data requires that you understand the system to which it applies.

Considering joint contribution to speed is not sufficient for the conclusion OILF is referring to. Movement involves the coupling (combining) of motion around different axes... and with that of the levers that actually do the moving.

Out in Left Field said:

... can you really control the end of a whip (which is moving forward several feet and going down with gravity before release) or do you just put it in position to do its work?

Click to expand...

This is another common misconception. Gravity is not the only force, nor is it the greatest. Additionally, it's an EXTERNAL force... meaning it's a force that is added OUTSIDE OF your control. Weight and friction are examples of other external forces. Muscle contractions, bony support, and ligamentous restraint are all INTERNAL forces. The forces generated INTERNALLY... MUST be GREATER THAN the EXTERNAL FORCES (gravity, weight, friction).

Muscles generate force that is transferred to the bones via tendons... and the bone will move IF the force is great enough. Force comes in simplest forms... as push and pull. External forces are more push, and internal forces are more pull... i.e force created by muscles PULLING on bones.

This brings me to the concept of levers. People often think of the wrong lever type when describing pitching. A first class lever in our body would be like the head... and it's attachment to the spine. The fulcrum is in the middle. A second class lever would be like doing a pushup. The fulcrum is at the end (the feet), the resistance in the middle, and the effort in the hands (pushing against the floor). In pitching... as it relates to generating ball speed through the arm... this would be a third-class type. Third class levers put the effort in the middle. These levers are built for SPEED and RANGE OF MOTION. This effort comes in the form of muscle (PULL)... and that muscle is often close to the joint.

In regards to this post... the elbow joint is the fulcrum, the forearm the lever, and the larger muscles (like the biceps) are the effort. The load is further away from the fulcrum than the effort... which results in the ability to create larger MOVEMENTS and greater SPEEDS... with proportionately smaller efforts (contractions).

So, the angles in our joints are important... as it is these angles THAT ALLOW force and speed production. As the angle in a joint changes, so does the moment arms... which creates differing mechanical advantages (like force and speed). Joints use flexion and extension (shortening and lengthening)... but they also RECEIVE torque.... which leads to angular momentum (the quantity of angular or rotational motion the levers have - think I/R and pronation).

If all that we used was the shoulder joint, we would not benefit nearly as much; the resultant velocity of this single lever is much slower... because a constant force must be applied in that region. However, if we desire a flowing continuous increase in speed... we must benefit from sending optimal forces through the joints and into the ball. Continuous flowing movements are additive... each subsequent force adds to the next. Meaning, the force from the shoulder adds to the force of the elbow, etc.

'Bend' in the elbow is a necessity... and there are optimal levels... because of something know as the moment of inertia. A straightened (extended) arm has a greater moment of inertia when compared to any degree of a 'bent' arm. Increasing the moment of inertia (like extending the elbow) will reduce rotational velocity.

Look, this stuff gets pretty complicated pretty fast. Joint angles, muscle lengths, contractile velocities, levers, muscle insertion locations, and neural components are all of equal importance. The latter, neural, is something that REQUIRES that athletes be TRAINED to OPTIMIZE movements. How many girls have we seen performing a straight arm pitch with their hand behind the ball... and all 'shoulder'? The repetition of this poor technique will create some level of muscle memory... and even though the body will try and maximize this movement, the movements themselves are NOT optimized. Proper muscle recruitment and synchronization (timing) of movements is paramount... as is the orientation and bend of the elbow... because without these... there is no way to optimally couple the forces into maximum speeds... through the kinetic linkage we call the arm.

The resultant coupled forces described above, result in over 5,200 degrees of rotational velocity per second in the 'best of the best'. Simply put... this is also the phase that the ball is released in... so getting the speed to the resultant lever is pretty freakin' important... and that... is the how to.

I know the term 'release of the ball' gives some people fits... but it is what it is. The when is something that many need training on, too. The release of the ball SHOULD happen at the midpoint of internal rotation AND the midpoint of pronation... BECAUSE... this is the point of greatest velocity. The flexion in the elbow allows for rotational velocity to be maximized.

An upper arm that can't decelerate (because the forearm doesn't accelerate) is a result of the lack of flexion in the elbow... and is the reason why many girls 'miss the whip'... releasing too far out front.

These are but a few of the reasons you train the last quarter... And no, none of this is stuff that everyone should just let happen. 99% of them need to be shown how to MAKE it happen. That is what training... and coaching is all about.

JS, I wished you would quit being so selfish.

JS has got a great point about the changing of the moment arm. It is a good way to think about the movement.

Basically, you are saying that the muscles "reconfigure" the moment arm by changing the angle between the forearm and the upper arm. The shorter moment arm with a bend results in greater angular velocity, and greater RPS.

This is a technical discussion, and again I think JS' stuff is great, I'm trying to understand.

The angular momentum is the same whether the arm is bent or not. The angular velocity increases with a bend in the arm, but when the arm straightens, the angular velocity of the arm decreases.

This is conservation of angular momentum...the total angular momentum within a system stays the same unless an external force is applied to the system (the system being defined as the forearm and upper arm). As the moment arm decreases, the rotation speed increases. As the moment arm increases, the rotation speed decreases.

If a pitcher uses brush resistance, an external force is applied to the system. The upper arm suddenly slows. However, the angular momentum of the system (approximately) will remain constant, so the angular momentum gets transferred to the forearm, resulting in an increase in speed to the forearm.

Another way to do it would be for the pitcher to stop the forearm with her muscles...which results in significant timing issues as well as possible damage to the bicep trying to slow down the upper arm.

The problem is that pitchers without brush resistance can throw 60+ mph. (There control sucks, but that is another issue.)

So, I'm wondering if the brush resistance results in an extra 2 or 3 MPH at the top end...so a pitcher jumps from 62 to 65 MPH. (As I've said many times, after 60 MPH, the pitcher is really working to add 2 MPH here and there.)

Just some quibbling:

with proportionately smaller efforts (contractions).

Click to expand...

That is incorrect. You have to use more effort to move a load a specified with a third class fulcrum than you do with a first class fulcrum. Perhaps you mean, "the distance moved is shorter".

So, the angles in our joints are important... as it is these angles THAT ALLOW force and speed production.

Click to expand...

???

I understand what you are saying, but that isn't quite correct. The changing angle of the arm, along with some mechanism to stop the upper arm, results in an increase in speed.

"Force" isn't the correct term. You are doing a pretty thorough discussion of engineering mechanics, so perhaps you should continue using "force" in that sense.

As the angle in a joint changes, so does the moment arms... which creates differing mechanical advantages (like force and speed).

Click to expand...

I get what you are saying...you are talking about the moment arm of the entire arm, not just the moment arm of the upper arm or forearm.

Joints use flexion and extension (shortening and lengthening)...

Click to expand...

I guess you mean "shortening and lengthening of the moment arm".

. but they also RECEIVE torque.... which leads to angular momentum (the quantity of angular or rotational motion the levers have - think I/R and pronation).

Click to expand...

This simply doesn't make any sense.

The upper arm has angular momentum because it is moving in a circle around the shoulder. The forearm has angular momentum because (1) it is rotating about the elbow and (2) it is rotating about the shoulder.

The forearm and upper arm externally rotate so that the hand is facing third base, and then it internally rotates.

If all that we used was the shoulder joint, we would not benefit nearly as much; the resultant velocity of this single lever is much slower... because a constant force must be applied in that region. However, if we desire a flowing continuous increase in speed... we must benefit from sending optimal forces through the joints and into the ball. Continuous flowing movements are additive... each subsequent force adds to the next. Meaning, the force from the shoulder adds to the force of the elbow, etc.

Click to expand...

Yes...I think it can be said much simpler as "a given force can generate more speed with two linked levers than with a single lever."

'Bend' in the elbow is a necessity... and there are optimal levels... because of something know as the moment of inertia. A straightened (extended) arm has a greater moment of inertia when compared to any degree of a 'bent' arm. Increasing the moment of inertia (like extending the elbow) will reduce rotational velocity.

Click to expand...

Like the spinning ice skater. If an ice skater wants to slow down the spin, she extends her arms. If she wishes to speed up her spin, she draws her arms to her body.

Look, this stuff gets pretty complicated pretty fast.

Click to expand...

And that is why we love it.

Joint angles, muscle lengths, contractile velocities, levers, muscle insertion locations, and neural components are all of equal importance. The latter, neural, is something that REQUIRES that athletes be TRAINED to OPTIMIZE movements. How many girls have we seen performing a straight arm pitch with their hand behind the ball... and all 'shoulder'? The repetition of this poor technique will create some level of muscle memory... and even though the body will try and maximize this movement, the movements themselves are NOT optimized. Proper muscle recruitment and synchronization (timing) of movements is paramount... as is the orientation and bend of the elbow... because without these... there is no way to optimally couple the forces into maximum speeds... through the kinetic linkage we call the arm.

Click to expand...

I think you are saying, "Perfect practice makes perfect."

The resultant coupled forces described above, result in over 5,200 degrees of rotational velocity per second in the 'best of the best'. Simply put... this is also the phase that the ball is released in... so getting the speed to the resultant lever is pretty freakin' important... and that... is the how to.

Click to expand...

Well, ultimately, the only thing that matters is how fast the ball is thrown.

I know the term 'release of the ball' gives some people fits... but it is what it is. The when is something that many need training on, too. The release of the ball SHOULD happen at the midpoint of internal rotation AND the midpoint of pronation... BECAUSE... this is the point of greatest velocity.

Click to expand...

Looks like we are back to "what do you mean by internal rotation"? There is a second internal rotation you are referring to, since pronation *is* internal rotation.

So, what is the second internal rotation? Or is this "internal rotation is the entire pitching motion"? Or do you mean the rotation of the hips from open to partially closed?

The flexion in the elbow allows for rotational velocity to be maximized.

Click to expand...

I.e., you can increase the rotational velocity of the arm by bending the elbow.

An upper arm that can't decelerate (because the forearm doesn't accelerate) is a result of the lack of flexion in the elbow... and is the reason why many girls 'miss the whip'... releasing too far out front.

Click to expand...

Good point...there is "no whip" where the arm is straight, and then there is "miss the whip", where the timing is off.

These are but a few of the reasons you train the last quarter... And no, none of this is stuff that everyone should just let happen. 99% of them need to be shown how to MAKE it happen. That is what training... and coaching is all about.

Click to expand...

Yep.

I'd bet that if you put braces on the wrist and elbow and used good technique including brush, you could get 90+ % of your top speed. I think the amazing ability of shoulder joint and an elbow bend of around 135 degrees are two of the greatest factors.

Sluggers,

First... know that I wrote this sitting on a bench in Target (while my wife was shopping). So, I completely admit that I didn't articulate some of these points that well, and I was really stoked to see that you took the time to ask for and provide clarification. Thanks.

Couple of notes on your comments/questions.. I'll keep them in order to your response:

I said:

Third class levers put the effort in the middle. These levers are built for SPEED and RANGE OF MOTION. This effort comes in the form of muscle (PULL)... and that muscle is often close to the joint.

In regards to this post... the elbow joint is the fulcrum, the forearm the lever, and the larger muscles (like the biceps) are the effort. The load is further away from the fulcrum than the effort... which results in the ability to create larger MOVEMENTS and greater SPEEDS... with proportionately smaller efforts (contractions).

Click to expand...

In a third-class lever, the load is further away from the fulcrum THAN the effort. In this arrangement, the mechanical advantage is lessened, because the effort is greater than the load. This disadvantage is compensated with a larger movement, yes... but this large movement of the forearm is a result of a comparatively smaller contraction of the biceps. Does that make sense?

Regarding my comment on the importance of angles... this was more about allowing the sequence of proximal to distal to happen. More of the flow/sequence that we should use... through joints. This pattern produces optimal forces and flowing, continuous movement.

Regarding the term "force"... and the push/pull you commented on originally: I really didn't word this well... probably because I was seeing 'red' (Target) for too long. I don't look at push as a force producer... in the context of the biomechanics involved in the last 1/4 of the circle. I know this might appear an odd statement but,IMO, we move because our muscles move. Muscles move by becoming shorter. They shorten and then they rest - in other words, a muscle can pull but it cannot push (resting is not force production... a muscle returning to it's resting length, that is). But together with their antagonist muscle pairings, the push/pull system we know of muscles... provide us with a complete set of motions. Does that make sense?

I'm trying to make this as simple as possible... and that can be tough to do when generalized terms are used... which is why I should've used the words agonist, antagonist, synergist, and fixator... but I didn't... mainly because I didn't have energy to define them then (and now before dinner).

Regarding the comment that "doesn't make sense".... it's because it's not a complete thought and very generalized. My bad.

Contracting muscles create an eccentric force (not the same as eccentric contraction) to bone that it is attached to... which causes the bone to rotate about an axis at the joint. The length of the force arm and the amount of force determine the torque. If you look at the last 1/4 of the circle... which is what I was writing about... the extension that occurs in the elbow - as we head into release, is due in part to a contraction of the triceps. When the triceps contracts, the force it produces creates torque at the ELBOW JOINT... which, believe it or not... creates an extension at the elbow joint... which is one of the reasons the tricep is known as an extensor. There is also a large amount of torque applied to the posterior shoulder areas DURING internal rotation... that act in an attempt to stabilize the musculature... so that the arm can continue to efficiently move along it's path... AS WELL AS provide deceleration mechanisms... which are required of the upper arm in order to accelerate the lower arm. This piece would tie nicely into your most recent thread.

Later on, you said...

Well, ultimately, the only thing that matters is how fast the ball is thrown.

Click to expand...

True dat... but students often equate ball speed to some pretty goofy mechanics that create just the opposite.

You then said...

Looks like we are back to "what do you mean by internal rotation"? There is a second internal rotation you are referring to, since pronation *is* internal rotation.

So, what is the second internal rotation? Or is this "internal rotation is the entire pitching motion"? Or do you mean the rotation of the hips from open to partially closed?

Click to expand...

To me... Internal Rotation is an articulation that originates in the shoulder... or glenohumeral. In simple terms... it's when you turn the upper arm inward. Pronation is an articulation that originates in the elbow. In simple terms... it occurs in the forearm. We can call them the same thing... but I TRULY PREFER DIFFERENTIATION. Sure... pronation is internal rotation of the forearm... but again, when you work with people day in and day out, it's important that you separate the movements for what they really are... because pronation/supination in the forearm can and does occur INDEPENDENTLY of the upper arm. Meaning, I can pronate/supinate my forearm without internally rotating my upper arm. This differentiation is one of the reasons I have success in showing pitchers new pitches. Knowing the pronation/supination difference also allows you to maximize the short stretch cycle in the last 1/4.

This can create a whole other conversation... as there is not doubt a ridiculous amount of power exhibited in a long-axis (single lever... no flexion in the elbow) pitch that comprises internal rotation... albeit not as much as a properly chained (proximal-distal) pitch that takes advantage of maximizing pronation.

Thanks, Sluggers. I hope I provided clarification - really appreciate you taking the time to respond. ~JS

Out in Left Field said:

OK. Let me repeat. I am not talking about the elbow angle at release. I am not talking about that graph at all. Keep going in the article to performance.

Yes, one can see the angle has changed at release from the back of the circle, and some angle is created I would think down the top of the back side of the circle. So that movement is only adding 4% speed.

Click to expand...

Keep repeating it if that helps you focus, but that doesn't change the fact that you're assuming you know what the author means by elbow contribution. You don't. The author does not state what she means by it. The only thing she states is that there is a stat defined as elbow angle at release. In the performance part of the report, there is no explanation of how elbow contribution is defined. Your assumption is just that, and one with no foundation to be found in the report.

Once upon a time someone steadfastly insisted that the NCAA rule book had a wider strike zone than than the rest of the world based on their interpretation of a picture in the rule book. Finally after posting the picture and explaining how they misinterpreted the picture the trolling stopped, at least on that subject. But I am sure it will come back around sometime so I saved the picture.

In 1996 when this journal was written they did not have the benefit of the slow motion cameras that we have today. So to break down the last 1/4 of the arm motion which is where, IMHO, the whip is "caught" would have been difficult. This journal is helpful but only when taken into context with what we know today based on slow motion video of top pitchers in the world. Levers and moments.....I think I will "drive" back to the ,"classroom". ��

javasource said:

To me... Internal Rotation is an articulation that originates in the shoulder... or glenohumeral. In simple terms... it's when you turn the upper arm inward. Pronation is an articulation that originates in the elbow. In simple terms... it occurs in the forearm. We can call them the same thing... but I TRULY PREFER DIFFERENTIATION. Sure... pronation is internal rotation of the forearm... but again, when you work with people day in and day out, it's important that you separate the movements for what they really are... because pronation/supination in the forearm can and does occur INDEPENDENTLY of the upper arm. Meaning, I can pronate/supinate my forearm without internally rotating my upper arm. This differentiation is one of the reasons I have success in showing pitchers new pitches. Knowing the pronation/supination difference also allows you to maximize the short stretch cycle in the last 1/4.

This can create a whole other conversation... as there is not doubt a ridiculous amount of power exhibited in a long-axis (single lever... no flexion in the elbow) pitch that comprises internal rotation... albeit not as much as a properly chained (proximal-distal) pitch that takes advantage of maximizing pronation.

Click to expand...

This has been my opinion all along. We have folks on this forum speaking of IR when often they are speaking of pronation.

I'm all for differentiating what is what. No reason to treat the humerus (upper arm) and forearm as one and the same.