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Online Joe Elliott

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A Question About Dr. Robert Zacharko.
« on: June 22, 2020, 04:24:52 PM »

A Question About Dr. Robert Zacharko.

Back in 1999, Michael Griffith, who recently rejoined this forum, sent an email to a Dr. Robert Zacharko, asking if the movements of JFK’s body just after the head shot of z-312, could be the result of the bullet passing through the brain. Dr. Zacharko responded with the surprising answer of “No”, even though there is a video of a goat which was shot through the head which causes its body to move pretty forcibly.

Questions:

1.   Did Michael Griffith mention to Dr. Robert Zacharko the film of the goat being shot through the head?

2.   Did Michael Griffith direct Dr. Robert Zacharko to a publication or website where he could see the film, or at least still frames from the film?


3.   Did Dr. Robert Zacharko actually ever observe an animal being shot through the brain or observe a film of such an event?

4.   Did Michael Griffith withhold from Dr. Robert Zacharko existence of a film of a goat being shot through the head because he feared he would not get a favorable opinion from him?

If Dr. Robert Zacharko’s opinion was not based on real world observations, however knowledgeable he may otherwise be, but only on armchair reasoning, then I would say his opinion was worthless.


These questions are pertinent because, as far as I know, no other medical expert has ever said that JFK’s movements during z313-z318 could not be the result of a neuromuscular spasm caused by a bullet passing through the brain. I wonder if the key to finding a medical expert with such an opinion is to find one who never saw a film of an animal being shot through the brain.

Offline Michael T. Griffith

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Re: A Question About Dr. Robert Zacharko.
« Reply #1 on: June 23, 2020, 02:36:58 PM »
I'm sorry, but I just have a hard time taking this line of questioning seriously. No neuro-muscular reaction is going to rocket a head backward in a fraction of a second when the head is moving rapidly forward. That is just nonsense.

Itek noted that from Z312-313 "the President's head is subjected to a large acceleration forward." Itek calculated that Kennedy's head is knocked forward 2.3 inches and his right shoulder about 1.1 inches from Z312-313. But, amazingly, in the very next frame, Z314, the head is suddenly moving backward.

Leaving aside the impossible reversal speed and impossible physics, there is also the fact that some of the brain needed for a neuro-muscular reaction was blasted out.

Finally, as for the goat video, did you even view the video before citing it? The goat's head barely moves at all in the video. The head is being held in place, but there is no sign that the head even tries to move. And the head shot to the goat obviously does not cause the explosion that occurred on JFK's head when the bullet struck it.

« Last Edit: June 23, 2020, 02:55:47 PM by Michael T. Griffith »

Online Joe Elliott

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Re: A Question About Dr. Robert Zacharko.
« Reply #2 on: June 23, 2020, 06:17:19 PM »

I'm sorry, but I just have a hard time taking this line of questioning seriously. No neuro-muscular reaction is going to rocket a head backward in a fraction of a second when the head is moving rapidly forward. That is just nonsense.

The neuro-muscular reaction didn’t push the head forward. The head was pushed forward about 2 inches, from z-312 to z-313, by the bullet that struck from behind. One frame later, roughly 55 milliseconds later, the neuro-muscular reaction started to push the head backwards, gradually building up speed though z-317. A bullet from the front would not cause such a gradual acceleration. Only a neuro-muscular reaction could do that.

Oh, and by the way, the limousine did accelerate during that time, but the acceleration was only one tenth as much as the acceleration of the head backward, so it wasn’t the limousine changing speed that accounts for this gradual acceleration of the head backwards.

What could account for that gradual acceleration other than the neuro-muscular reaction. A stream of bullet from the front, strike the head with each Zapruder frame?



Itek noted that from Z312-313 "the President's head is subjected to a large acceleration forward." Itek calculated that Kennedy's head is knocked forward 2.3 inches and his right shoulder about 1.1 inches from Z312-313. But, amazingly, in the very next frame, Z314, the head is suddenly moving backward.

Not amazing. The Goat starts moving its body 40 milliseconds after the bullet struck. So, the very next frame, roughly 55 milliseconds later, JFK’s head starts moving as well.



Leaving aside the impossible reversal speed and impossible physics, there is also the fact that some of the brain needed for a neuro-muscular reaction was blasted out.

Did Dr. Zacharko say that? Has any doctor said that? Actually, it doesn’t matter what part of the brain gets blasted out, as it didn’t matter with the goat. The brain doesn’t get the commands but instead it is generated when the spinal cord is stretched.



Finally, as for the goat video, did you even view the video before citing it? The goat's head barely moves at all in the video. The head is being held in place, but there is no sign that the head even tries to move. And the head shot to the goat obviously does not cause the explosion that occurred on JFK's head when the bullet struck it.


I have seen the goat video many times.

The goat’s head did not move because it was impossible. The goat’s head was locked into place so the goat could remain standing while unconscious from drugs before it was shot. That is why the head is still high in the air while the rest of the body was collapsed at the end of the video. If JFK’s head was locked into place with metal clamps, his head wouldn’t have moved either.

But yes, I think this test could be redone, this time with the goat conscious and its whole body free to move. Thousands of animals are slaughtered each year so I think this could be done and is a pretty humane death. I do not have a rifle, a film camera or even a goat for repeating this experiment. But I think it should be done.



Questions:

But the questions I’m most interested in are:

1.   Why isn’t your communication with Dr. Zacharko on your JFK assassination website? Did he ask you to not display it anymore?

2.   Did you alert Dr. Zacharko to the existence of this video showing the goat being shot through the brain? Or did you decide to keep it a secret from him, for fear that if he knows about it, he wouldn’t give a favorable opinion?


Offline Michael T. Griffith

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Re: A Question About Dr. Robert Zacharko.
« Reply #3 on: June 23, 2020, 06:47:08 PM »
The neuro-muscular reaction didn’t push the head forward. The head was pushed forward about 2 inches, from z-312 to z-313, by the bullet that struck from behind. One frame later, roughly 55 milliseconds later, the neuro-muscular reaction started to push the head backwards, gradually building up speed though z-317. A bullet from the front would not cause such a gradual acceleration. Only a neuro-muscular reaction could do that.

I think this is fairy tale material. Several other scholars have debunked the neuro-muscular reaction theory as an explanation for the backward head snap. So I won't reinvent the wheel here (more on this below).

Oh, and by the way, the limousine did accelerate during that time, but the acceleration was only one tenth as much as the acceleration of the head backward, so it wasn’t the limousine changing speed that accounts for this gradual acceleration of the head backwards.

Again, no neuro-muscular reaction is going to reverse the rapid forward movement of a head in a split-second amount of time. Even some lone-gunman theorists have ditched this theory and have posited a "jet effect," which is even more problematic.

What could account for that gradual acceleration other than the neuro-muscular reaction. A stream of bullet from the front, strike the head with each Zapruder frame?

"Gradual acceleration"?! Really? Are we talking about the same film? There is nothing "gradual" about it: it is violent and rapid, unless you watch the film in super slow motion.

Not amazing. The Goat starts moving its body 40 milliseconds after the bullet struck. So, the very next frame, roughly 55 milliseconds later, JFK’s head starts moving as well.

But we're not talking about the body, and Kennedy's body shows no such reaction anyway. We're talking about the head. Although the goat's head is being held in place, there is not so much as an inkling that its head attempts to move, and there is no explosion from the bullet's impact, which suggests they used the wrong kind of ammo.

There's also the fact, pointed out by Dr. Joe Riley, that the neurobiology and neurophysics of a goat are completely different from those of a human.

Did Dr. Zacharko say that? Has any doctor said that? Actually, it doesn’t matter what part of the brain gets blasted out, as it didn’t matter with the goat. The brain doesn’t get the commands but instead it is generated when the spinal cord is stretched.

I have seen the goat video many times.

The goat’s head did not move because it was impossible. The goat’s head was locked into place so the goat could remain standing while unconscious from drugs before it was shot. That is why the head is still high in the air while the rest of the body was collapsed at the end of the video. If JFK’s head was locked into place with metal clamps, his head wouldn’t have moved either.

But you would be able to see the head try to move. You would see skin and muscle flex/shift as the head attempted to respond to the force of the impact, and we see no such activity in the goat video.

But yes, I think this test could be redone, this time with the goat conscious and its whole body free to move. Thousands of animals are slaughtered each year so I think this could be done and is a pretty humane death. I do not have a rifle, a film camera or even a goat for repeating this experiment. But I think it should be done.

Yeah, and they could start by using the right kind of ammunition. The cloud of fragments toward of the front of JFK's skull indicates that is where the bullet impacted and then shattered. Even Sturdivan admitted that if the head were struck in the right front, you would expect to see a cloud of fragments in the right-front part of the head.

We know that the bullet that struck the back of the skull could not have been the type of bullet that Oswald allegedly used. The entry hole was only 6 mm. Oswald's alleged ammo was 6.5 mm. Bullets always make entry points that are slightly larger than their own size--this is just physics, not to mention common sense. This was one of the things that alerted Howard Donahue that the Warren Commission's claims about the rear head entry wound were impossible.

Here is the entirety of my correspondence with Dr. Zacharko:

I asked Dr. Robert Zacharko, a neuroscientist at Carleton University in
Canada, about the theory that JFK's backward head snap was caused by a
neuromuscular reaction.  I wrote to him as follows:

       In frames 312-313 of the Zapruder film, we see Kennedy's head knocked
       forward, but then, suddenly, beginning in frame 314, we see his head and
       upper body jolted violently backward and to the left as the right frontal
       area of his skull explodes.  One theory says that this violent backward
       motion was the result of a neuromuscular reaction.  This reaction would
       have had to occur in no more than 56 milliseconds.  I have two questions
       about this theory:

       1.  Some object to this theory on the basis that the reaction could not
       have occurred so quickly.  They point out that the fastest involuntary
       reaction known to man is the eye blink, which takes about 40
       milliseconds. They argue that this indicates that the backward head snap
       would have taken longer to occur, since it involved much more mass.  One
       author phrases this objection as follows:

            . . . it [the head] is suddenly driven forward between frames 312
            and 313.  Amazingly, in the very next frame, 314, it is already
            moving backward, a movement it continues in succeeding frames until
            the President's shoulders strike the seat cushion at Z321. . . .
            The extremely small time factor combined with the relatively
            large mass of the President's head would tend to rule out
            such an explanation [i.e., the neuromuscular-reaction theory].
            The fastest reflex reaction known to science--the startle
            response--takes place over an interval of 40 to 200
            milliseconds.  Beginning with an eyeblink in 40 milliseconds,
            the response wave moves the head forward in 83 milliseconds,
            and then continues downward reaching the knees in 200 milliseconds.
            The change in direction we observe [in the head snap] occurs in 56
            milliseconds (1/18th/second), and involves not the negligible mass
            of an eyelid but the considerable mass of a human head
            moving forward with an acceleration of several g's.

       What is your opinion on the speed of the alleged neuromuscular reaction?

       2. One author has objected to the neuromuscular-reaction theory on the
       following basis:

            A "massive neuromuscular reaction," according to Messrs. Ford
            and Belin, occurs when there is "massive damage inflicted to nerve
            centers of the brain."  The nerve centers of the brain are the
            pons, the medulla, the cerebellum--all located in the rear of the
            brain. According to the Warren Commission and the HSCA, the head
            shot damaged the right cerebral hemisphere of Kennedy's
            brain--not a nerve coordination center, not capable of causing
            a "massive neuromuscular reaction."

            The neuromuscular reaction that supposedly accounts for
            the backward snap of Kennedy's head when struck by a
            bullet from behind could happen only if a major coordinating
            center of the brain is damaged.  According to the x-rays and
            autopsy photos that lone-gunman theorists champion as
            evidence of a shot from behind, those areas of the brain
            are intact.

       What is your opinion of this objection to the neuromuscular-reaction
       theory?

Dr. Zacharko responded as follows in an e-mail dated 8 February 1999:

       If you ask any neuroscientist what a neuromuscular effect is they will
       tell you that it refers to some interface of nerve and muscle for
       example. In some cases a simple reflex response (e.g., knee jerk for
       example). Can certain reflexes be influenced? Certainly. Do head
       movements fall into such a category? No. The head movements that you are
       referring to are following the laws of physics. With all due respect to
       Belin and Ford I would ask what medical references or more precisely what
       research references are being using to document arguments of
       neuromuscular reactivity. Simply stated there are none. The pons and
       medulla contain centres for respiration, cardiovascular regulation,
       visceral reactivity and the like. The cerebellum is also present at this
       level. Damage to these areas will interrupt respiration and heart rhythm
       and affect motor coordination. Neural damage per se associated with
       bullet entry will not cause exaggerated head movement of the type you see
       in the Zapruder film. In fact there are no brain sites that will. This
       neuromuscular reactivity argument is simply nonsense.[Note: One could
       make the argument, ludicrous as it may sound, that Kennedy actually saw
       the bullet approaching and jerked his head back reflexively to avoid
       being hit.]

       The second author does not appear to be any more informed than either
       Belin or Ford. There is no such thing as a major coordinating centre.
       Those arguments were largely discounted in the 1960's. The brain simply
       does not act in such a fashion. It is a coordinated system. Actually
       there is a system which is referred to as the extrapyramidal motor
       system, which runs from the mesencephalon to the forebrain. It controls
       voluntary movement. If this system was to discharge, you would effect
       gross motor output. Such discharge would typically represent the invasion
       of seizure like activity to motor areas. It would not be coordinated and
       certainly not of the type evident in the Zapruder film.

       The bottom line is that the head movements are reactions to the direction
       of bullet entry. They are not the product of central nervous system
       damage. It would almost seem that certain myths are maintained in the
       absence of documented data. Information from half-sources of
       documentation appear to blend with legitimate sources of information to
       provide muddled scenarios.
       
                                       Sincerely,

                                       Dr Robert M. Zacharko
                                       Life Sciences Research Building
                                       Institute of Neuroscience
                                       Carleton University
                                       Ottawa, Ontario, Canada

« Last Edit: June 23, 2020, 07:09:57 PM by Michael T. Griffith »

Online Joe Elliott

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Re: A Question About Dr. Robert Zacharko.
« Reply #4 on: June 23, 2020, 07:30:10 PM »

Ok. You have not answered either question directly, but it is clear from your correspondence that you provided with Dr. Robert Zacharko that you did not inform him of the existence of the goat video.

This is strange, because an expert giving an opinion needs to be made aware of the principle arguments of the other side, be they valid or invalid. Anyone arguing for the neuro-muscular reaction hypothesis will cite the goat video as the principle piece of evidence. Clearly animal muscles can be activated as a result of a bullet passing through the brain. The point could not be made any clearer.


It doesn’t matter that you think the goat video has no relevance. Dr. Zacharko needs to be made aware of this video and decide for himself if it has relevance or not. If he is to give an informed opinion.


So, for Dr. Zacharko to argue against the neuro-muscular reaction hypotheses, he needs to acknowledge that he has seen the principle evidence of the other side and argue either:

1.   The muscles of the goat are not activated by the bullet passing through the brain.

This would be an absurd argument.

Or:

2.   A neuro-muscular reaction is to be expected in a goat but not in a human.

I doubt a medical doctor would give such an opinion. But if I am wrong, I would like to hear his arguments.

Unfortunately. we never got to hear Dr. Zacharko’s opinion on the relevance of the goat video because you decided to withhold from him the principle piece of evidence cited by LNers. I would suggest that you did so because you feared you would not get a favorable opinion from Dr. Zacharko if he knew of it, but you might if he didn’t.

I only have one simple question that I would like answered.

Question:

1.   Does an expert need to know the principle pieces of evidence, cited by both sides, to give an informed opinion on a question of dispute?


Offline Michael T. Griffith

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Re: A Question About Dr. Robert Zacharko.
« Reply #5 on: June 23, 2020, 08:57:20 PM »
Here is my section on the neuro-muscular reaction and jet-effect theories in my book Hasty Judgment:

Posner attempts to explain why the Zapruder film shows JFK's upper body rocketing backward in reaction to the fatal head shot (6:315-316). Citing the work of Drs. Luis Alvarez and John Lattimer, Posner says the backward snap of Kennedy's upper body resulted, not from a shot from the front, but from a neuromuscular reaction and the so-called "jet effect" after a bullet entered JFK's head from behind.

This is a far cry from the days when Warren Commission member Allen Dulles denied the Zapruder film showed Kennedy moving backward in response to the final shot. Gone, too, are the days when it was proposed that the limousine suddenly lurched forward at the precise moment of the last shot and thus caused the President's fierce backward motion. We can also rest assured that CBS's Dan Rather will never again tell a nationwide audience, as he did the day after the assassination, that in the Zapruder film Kennedy's head is thrust forward by the final shot (although Rather might have been describing a hit on JFK's head that was later almost completely deleted from the Zapruder film--see below).

Now we are told the President was indeed rocketed violently backward but that this movement was caused by a neuromuscular reaction and/or by the jet effect. There are serious problems with these theories. Neither is really credible. One expert told the HSCA that neuromuscular reactions normally do not begin for several minutes after the upper brain centers have been separated from the brain stem and the spinal cord, and such reactions do not resemble Kennedy's response to the fatal head shot. Former Rockefeller Foundation fellow Henry Hurt explained:

Quote
By 1975, when a copy of the Zapruder film was shown on national television, the violent rearward head-snap at last had to be given some official explanation. The HSCA addressed the question and heard expert testimony [from one questionable expert] that the motion of Kennedy's body could have been a neurological spasm. According to the Select Committee report, the expert concluded that "nerve damage from a bullet entering the President's head could have caused his back muscles to tighten which, in turn, could have caused his head to move toward the rear." A motion picture was shown of a goat being shot in the head, causing all the goat's muscles to go into a violent, involuntary spasm. Clearly, this does not appear to be what happened to Kennedy, whose whole appears to go limp as he is thrown backward. There is no splaying of his limbs, as in the shooting of the goat. (71:129-130).

Josiah Thompson notes that the neuromuscular-reaction theory conflicts with what is known about human reflex actions:

Quote
The extremely small time factor combined with the relatively large mass of the President's head would tend to rule out such an explanation. The fastest reflex action known to science--the startle response--takes place over an interval of 40 to 200 milliseconds. Beginning with an eyeblink in 40 milliseconds, the response wave moves the head forward in 83 milliseconds, and then continues downward reaching the knees in 200 milliseconds. The change in direction we observe [i.e., the change from the forward motion of JFK's head to the more violent rearward motion] occurs in 56 milliseconds (1/18th second), and involves not the negligible mass of an eyelid but the considerable mass of a human head moving forward under an acceleration of several g's. (59:93)

I asked Dr. Robert Zacharko, a neuroscientist at Carleton University in Canada, about the theory that JFK's backward head snap was caused by a neuromuscular reaction.  I wrote to Dr. Zacharko as follows:

In frames 312-313 of the Zapruder film, we see Kennedy's head knocked forward, but then, suddenly, beginning in frame 314, we see his head and upper body jolted violently backward and to the left as the right frontal area of his skull explodes.  One theory says that this violent backward motion was the result of a neuromuscular reaction.  This reaction would have had to occur in no more than 56 milliseconds.  I have two questions about this theory:

1. Some object to this theory on the basis that the reaction could not have occurred so quickly.  They point out that the fastest involuntary reaction known to man is the eye blink, which takes about 40 milliseconds. They argue that this indicates that the backward head snap would have taken longer to occur, since it involved much more mass.  One author phrases this objection as follows:
         
Quote
. . . it [the head] is suddenly driven forward between frames 312 and 313.  Amazingly, in the very next frame, 314, it is already moving backward, a movement it continues in succeeding frames until the President's shoulders strike the seat cushion at Z321. . . . The extremely small time factor combined with the relatively large mass of the President's head would tend to rule out such an explanation [i.e., the neuromuscular-reaction theory].
         
The fastest reflex reaction known to science--the startle response--takes place over an interval of 40 to 200 milliseconds.  Beginning with an eyeblink in 40 milliseconds, the response wave moves the head forward in 83 milliseconds, and then continues downward reaching the knees in 200 milliseconds. The change in direction we observe [in the head snap] occurs in 56 milliseconds (1/18th/second), and involves not the negligible mass of an eyelid but the considerable mass of a human head moving forward with an acceleration of several g's.

What is your opinion on the speed of the alleged neuromuscular reaction?

2. One author has objected to the neuromuscular-reaction theory on the following basis:
         
Quote
A "massive neuromuscular reaction," according to Messrs. Ford and Belin, occurs when there is "massive damage inflicted to nerve centers of the brain."  The nerve centers of the brain are the pons, the medulla, the cerebellum--all located in the rear of the brain. According to the Warren Commission and the HSCA, the head shot damaged the right cerebral hemisphere of Kennedy's brain--not a nerve coordination center, not capable of causing a "massive neuromuscular reaction."
         
The neuromuscular reaction that supposedly accounts for the backward snap of Kennedy's head when struck by a bullet from behind could happen only if a major coordinating center of the brain is damaged.  According to the x-rays and autopsy photos that lone-gunman theorists champion as evidence of a shot from behind, those areas of the brain are intact.

What is your opinion of this objection to the neuromuscular-reaction theory?

Dr. Zacharko responded as follows in an e-mail dated 8 February 1999:

Quote
If you ask any neuroscientist what a neuromuscular effect is they will tell you that it refers to some interface of nerve and muscle for example. In some cases a simple reflex response (e.g., knee jerk for example). Can certain reflexes be influenced? Certainly. Do head movements fall into such a category? No. The head movements that you are referring to are following the laws of physics. With all due respect to Belin and Ford I would ask what medical references or more precisely what research references are being using to document arguments of neuromuscular reactivity. Simply stated there are none. The pons and medulla contain centres for respiration, cardiovascular regulation, visceral reactivity and the like. The cerebellum is also present at this level. Damage to these areas will interrupt respiration and heart rhythm and affect motor coordination. Neural damage per se associated with bullet entry will not cause exaggerated head movement of the type you see in the Zapruder film. In fact there are no brain sites that will. This neuromuscular reactivity argument is simply nonsense.  [Note: One could make the argument, ludicrous as it may sound, that Kennedy actually saw the bullet approaching and jerked his head back reflexively to avoid being hit.]

The second author does not appear to be any more informed than either Belin or Ford. There is no such thing as a major coordinating centre. Those arguments were largely discounted in the 1960's. The brain simply does not act in such a fashion. It is a coordinated system. Actually there is a system which is referred to as the extrapyramidal motor system, which runs from the mesencephalon to the forebrain. It controls voluntary movement. If this system was to discharge, you would effect gross motor output. Such discharge would typically represent the invasion of seizure like activity to motor areas. It would not be coordinated and certainly not of the type evident in the Zapruder film.

The bottom line is that the head movements are reactions to the direction of bullet entry. They are not the product of central nervous system damage. It would almost seem that certain myths are maintained in the absence of documented data. Information from half-sources of documentation appear to blend with legitimate sources of information to provide muddled scenarios.
Sincerely,

Dr Robert M. Zacharko, Life Sciences Research Building, Institute of Neuroscience, Carleton University, Ottawa, Ontario, Canada

As for the jet-effect hypothesis, ballistics expert Larry Sturdivan gave testimony to the HSCA that tended to refute the theory, and he himself seemed to implicitly reject it. Among other things, Sturdivan pointed out that the right-frontal explosion seen in the Zapruder film would not have had sufficient force to rapidly propel JFK's upper body backward and to the left (1 HSCA 423). Furthermore, Sturdivan noted that whatever force was created by the right-frontal spray would have pushed Kennedy straight to the left, not backward and to the left. Some proponents of the jet-effect theory appeal to Newton's third law as support for the idea, but physics instructor Ken Degazio argues this suggestion is invalid (10:367-368). 

Lone-gunman theorists cite Dr. Luis Alvarez's experiments with melons, saying the experiments prove the jet-effect theory is plausible.  Mechanical engineer Tony Szamboti explains why Alvarez's tests aren't relevant and details one of the reasons the jet-effect theory is implausible:

Quote
The requirements for the “jet effect” to dominate and cause a motion towards the shooter are threefold and they are; the early development of a temporary cavity pressure, a low shear force through the skin or casing of the object, and an entrance side sealing of the permanent cavity. Although a “jet effect” may have occurred in Dr. Alvarez’s melon tests, the main trick was in using an object with a soft skin or casing (the melon) to reduce the shear force. The early temporary cavity produced by the lead projectile of the hunting ammunition also helped. The taping of the melon rind would allow it to resist any hoop stress due to internal pressure. Since the tensile strength of the melon rind is low, hoop stress could have caused a fracture and spoiled the test. The tape would also provide for a small entrance and better chance for permanent cavity sealing at the entrance side. The use of tape on the melons also provided these advantages without truly replicating the human skull. While the tape would tend to mock up the tensile strength of the human cranium, it would not enhance the shear strength very much. It is the shear strength that is operative here not the tensile strength. The melon tests were thus misleading and the “jet effect” seen on the melons, with the use of hunting ammunition and tape, really has no place in attempting to explain away the back and to the left head motion of President Kennedy as being possible if hit from the rear.

The shear forces generated by the bullet penetrating through the much higher shear strength of the President’s skull would preclude the appearance of a “jet effect” induced motion in the assassination. This was demonstrated at the Army's Edgewood Arsenal in 1978 during testing done for the HSCA. Ten human skulls, filled with the same tissue replicating material as that used by the Army Wound Ballistics Research program, were shot with 6.5 millimeter ammunition and all 10 skulls went forward, in the direction of the bullet. None went backward. (85:9-10)

Advocates of the jet-effect theory not only assume that the bullet came from behind, but also that no substantial amount of skull, if any at all, was blown out from the right rear part of the head. Yet, as we have seen, there is compelling eyewitness testimony, supported by the original Parkland Hospital reports, that there was a large, exit-type wound in the right rear area of Kennedy's head.
In 1988 3M's Comtal Corporation analyzed the fatal head shot in the Nix film. Comtal specializes in photographic analysis through computerized enhancements. Jack Anderson reported in his 1988 documentary Who Murdered JFK? that the Comtal study determined that "the fatal gunshot came from in front of the president's car . . . from the grassy knoll."

How does Posner explain the fact that the police officers who were riding to the left rear of the limousine were forcefully splattered with JFK's blood and brain tissue? He resorts to invention. He claims that in an "enhanced" version of the Zapruder film "the two officers drive right into the head spray, which actually shot up and to the front of the President" (6:316 n).  The Zapruder film shows no such thing.  The spray from the right frontal explosion blows mostly forward and also upward and toward Zapruder's camera, as Dr. Sturdivan noted during the HSCA hearings, and it dissipates very quickly. And, as will be discussed below, if a large amount of the spray had blown to the left side of the limousine, it would have plastered Mrs. Kennedy, but the Zapruder film clearly shows this did not occur.

As for the direction of the spray from Kennedy's head, much of it was blown backward, not just forward, indicating a shot from the front. Officer Hargis, riding just behind the limousine's left rear bumper, was splattered by blood and brain matter, and was struck so forcefully by a particulate matter that at first he thought he himself had been hit (Itek's experts acknowledged that this is the plain sense of Hargis's statements on the subject). Officer B. J. Martin, who was on Hargis's left, looked to his right after the first shots; later, he found blood stains on the left side of his helmet, as well as on his windshield. Only blood spraying from the rear of JFK's head could have reached all the way out to Officer Martin. There is also the fact that a piece of skull from the rear of the President's head was blown backward and to the left by the fatal head shot (5:13-15; 10:172; 18:316-317; cf. 18:530-533). There are indications that one skull fragment, known as the Harper fragment, was blown backward with such force that it flew at least ten feet before landing, although the FBI inexplicably failed to establish exactly where the fragment landed (14:32; 2:231). Dealey Plaza witness Charles Brehm, who was standing across the street from the grassy knoll, saw a piece of skull blown backward and to the left when the fatal shot struck the President (18:44, 96, 316, 331 n).

Online Joe Elliott

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Re: A Question About Dr. Robert Zacharko.
« Reply #6 on: June 23, 2020, 11:47:08 PM »

This is a far cry from the days when:
                        Warren Commission member Allen Dulles denied the Zapruder film showed Kennedy moving backward in response to the final shot.

The members of the Warren Commission did not see the film, so any statement by Allen Dulles was a guess.

                       Gone, too, are the days when it was proposed that the limousine suddenly lurched forward at the precise moment of the last shot and thus caused the President's fierce backward motion.

I never heard a LNer claim a lurch from the limousine caused the President’s head to go backward. I have heard CTers claim the acceleration of JFK’s head backwards over a quarter of a second was caused by the limousine accelerating, which is a false claim. I’ve heard that claim quite recently, on this board. I don’t have to reach back fifty years.

                       We can also rest assured that CBS's Dan Rather will never again tell a nationwide audience, as he did the day after the assassination, that in the Zapruder film Kennedy's head is thrust forward by the final shot.

Only another example of why we should not trust eyewitnesses, even professional reporters. Dan Rather was trusting in his memory. And he wasn’t asked to note if the head moved backwards before seeing the film, then saw the film, then reported it did not move backwards. The question first came up after he saw the film, could not refer to it before answering and answered it wrong.

Now we are told the President was indeed rocketed violently backward but that this movement was caused by a neuromuscular reaction and/or by the jet effect. There are serious problems with these theories. Neither is really credible. One expert told the HSCA that neuromuscular reactions normally do not begin for several minutes after the upper brain centers have been separated from the brain stem and the spinal cord, and such reactions do not resemble Kennedy's response to the fatal head shot. Former Rockefeller Foundation fellow Henry Hurt explained:

No. Only CTers lie and tell us that the President’s head rocketed violently backward.

The Zapruder film shows, which you can check Physics graduate student’s William Hoffman work which he did for Josiah Thompson’s “Six Seconds in Dallas”:

https://archive.org/details/SixSecondsInDallas/page/n103/mode/2up

That initially, the head moved forward 2.3 inches between two Zapruder frames. Then it moved back
          z-312-313: moved forward 2.3 inches
          z-313-314: moved backward 0.6 inches
          z-314-315: moved backward 0.9 inches
          z-315-316: moved backward 1.2 inches, and reached the z-312 position
          z-316-317: moved backward 1.4 inches
          z-317-318: moved backward 1.8 inches
From z313-318, over a quarter of a second, the head accelerated backwards

From z313 through z318, over a quarter of a second period, it accelerated from 0.0 mph to 1.9 mph. 2 mph is not being moved violently.

This is not in accordance to Physics if the explanation you want is from a single bullet from the front. I know, I took Classic Physics in college. If the movement was caused by a bullet, all the momentum exchange would take place in a millisecond. You would not see an acceleration over the next quarter second.

Never, have I seen a CTer even attempt to explain how a bullet could cause an acceleration of the head over a quarter of a second period, from z313 through z318. Never.


I asked Dr. Robert Zacharko, a neuroscientist at Carleton University in Canada, about the theory that JFK's backward head snap was caused by a neuromuscular reaction.  I wrote to Dr. Zacharko as follows:

You now repeat again what you said to Dr. Zacharko and how he responded. And how you left Dr. Zacharko in ignorance of the goat film. So, whatever opinion he has is based on ignorance.

I would like an expert who addresses the neuro-muscular reaction hypothesis to know three things:

1.   Observe a film of an animal being shot though the brain. Like the film of the goat. To see the reaction from the body.

2.   To have studied the work of William Hoffman, and to know that the movement backwards of the President’s head was a gradual acceleration that lasted over a quarter of a second. And, ideally, study the Zapruder film carefully, frame by frame, to see if William Hoffman got it right.

3.   To understand basic Classical Physics. To know that a bullet that passes through a target in a millisecond isn’t going to cause that object to gradually accelerate away from the shooter during the next quarter second. Instead, such an interaction would cause the transfer of momentum to take place within a millisecond, thereafter the target should move away from the shooter at a constant speed, with constant momentum.


At a minimum, at a minimum, an expert would have to know these three things. He could argue goats are different than humans. He could say he thinks William Hoffman did not do a good job. He could say that Classical Physics is just wrong and not to be trusted, no more than the Theory of Evolution. But he has to be aware of these three facts.


As for the jet-effect hypothesis, …

I reject the jet-effect hypotheses. Yes, it happens with taped melons. But these targets start moving back toward the shooter immediately, within a few milliseconds as the melon explodes. JFK’s head doesn’t start moving backwards for roughly 55 milliseconds. So, let’s not waste anymore time on the jet-effect hypotheses.


How does Posner explain the fact that the police officers who were riding to the left rear of the limousine were forcefully splattered with JFK's blood and brain tissue? He resorts to invention. He claims that in an "enhanced" version of the Zapruder film "the two officers drive right into the head spray, which actually shot up and to the front of the President" (6:316 n).  The Zapruder film shows no such thing.  The spray from the right frontal explosion blows mostly forward and also upward and toward Zapruder's camera, as Dr. Sturdivan noted during the HSCA hearings, and it dissipates very quickly. And, as will be discussed below, if a large amount of the spray had blown to the left side of the limousine, it would have plastered Mrs. Kennedy, but the Zapruder film clearly shows this did not occur.

The limousine was going 8 mph directly into a 10-15 mph head wind. Any bloody spray that exists will be blown backwards onto the trailing motorcycle offices. The cloud will approach them at a speed of 18-23 mph. Posner’s explanation is not a fantastic explanation but a reasonable one.

The Zapruder film shows the spray go upward and forward and then fade from view, as if it passed from existence. Except it couldn’t have passed into non-existence. It must have become too dispersed to see and we would expect the wind to blow it back onto the trailing officers at 18-23 mph. I don’t know if that happened, but it sounds reasonable. Maybe the bloody spray immediately dived into the ground like a lead ball, but I suspect it would stay suspended in the air for a second, long enough for the officers to drive through it.



But let’s not continue to go off on tangents, on bloody spray, jet-effect hypothesis, what was said fifty years ago, etc.

Questions:

Why was Dr. Zachanko kept in ignorance of film of the goat?

Why was Dr. Zachanko kept in ignorance of the William Hoffman study?

In the future, would you make certain a medical expert was made aware of my three points when you ask them if the neuro-muscular reaction hypothesis could be true?

When to you expect the CTers will find a single doctor, in the world, he knows about the three points I listed and still rejects the neuro-muscular reaction hypothesis? It’s been over 50 years. Do you think this will ever happen?


Offline Michael T. Griffith

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Re: A Question About Dr. Robert Zacharko.
« Reply #7 on: June 24, 2020, 09:58:35 PM »
The members of the Warren Commission did not see the film, so any statement by Allen Dulles was a guess.

I never heard a LNer claim a lurch from the limousine caused the President’s head to go backward. I have heard CTers claim the acceleration of JFK’s head backwards over a quarter of a second was caused by the limousine accelerating, which is a false claim. I’ve heard that claim quite recently, on this board. I don’t have to reach back fifty years.

Only another example of why we should not trust eyewitnesses, even professional reporters. Dan Rather was trusting in his memory. And he wasn’t asked to note if the head moved backwards before seeing the film, then saw the film, then reported it did not move backwards. The question first came up after he saw the film, could not refer to it before answering and answered it wrong.

No. Only CTers lie and tell us that the President’s head rocketed violently backward.

The Zapruder film shows, which you can check Physics graduate student’s William Hoffman work which he did for Josiah Thompson’s “Six Seconds in Dallas”:

https://archive.org/details/SixSecondsInDallas/page/n103/mode/2up

That initially, the head moved forward 2.3 inches between two Zapruder frames. Then it moved back
          z-312-313: moved forward 2.3 inches
          z-313-314: moved backward 0.6 inches
          z-314-315: moved backward 0.9 inches
          z-315-316: moved backward 1.2 inches, and reached the z-312 position
          z-316-317: moved backward 1.4 inches
          z-317-318: moved backward 1.8 inches

From z313-318, over a quarter of a second, the head accelerated backwards

From z313 through z318, over a quarter of a second period, it accelerated from 0.0 mph to 1.9 mph. 2 mph is not being moved violently.

This is not in accordance to Physics if the explanation you want is from a single bullet from the front. I know, I took Classic Physics in college. If the movement was caused by a bullet, all the momentum exchange would take place in a millisecond. You would not see an acceleration over the next quarter second.

Never, have I seen a CTer even attempt to explain how a bullet could cause an acceleration of the head over a quarter of a second period, from z313 through z318. Never.

You now repeat again what you said to Dr. Zacharko and how he responded. And how you left Dr. Zacharko in ignorance of the goat film. So, whatever opinion he has is based on ignorance.

I would like an expert who addresses the neuro-muscular reaction hypothesis to know three things:

1.   Observe a film of an animal being shot though the brain. Like the film of the goat. To see the reaction from the body.

2.   To have studied the work of William Hoffman, and to know that the movement backwards of the President’s head was a gradual acceleration that lasted over a quarter of a second. And, ideally, study the Zapruder film carefully, frame by frame, to see if William Hoffman got it right.

3.   To understand basic Classical Physics. To know that a bullet that passes through a target in a millisecond isn’t going to cause that object to gradually accelerate away from the shooter during the next quarter second. Instead, such an interaction would cause the transfer of momentum to take place within a millisecond, thereafter the target should move away from the shooter at a constant speed, with constant momentum.


At a minimum, at a minimum, an expert would have to know these three things. He could argue goats are different than humans. He could say he thinks William Hoffman did not do a good job. He could say that Classical Physics is just wrong and not to be trusted, no more than the Theory of Evolution. But he has to be aware of these three facts.

I reject the jet-effect hypotheses. Yes, it happens with taped melons. But these targets start moving back toward the shooter immediately, within a few milliseconds as the melon explodes. JFK’s head doesn’t start moving backwards for roughly 55 milliseconds. So, let’s not waste anymore time on the jet-effect hypotheses.

The limousine was going 8 mph directly into a 10-15 mph head wind. Any bloody spray that exists will be blown backwards onto the trailing motorcycle offices. The cloud will approach them at a speed of 18-23 mph. Posner’s explanation is not a fantastic explanation but a reasonable one.

The Zapruder film shows the spray go upward and forward and then fade from view, as if it passed from existence. Except it couldn’t have passed into non-existence. It must have become too dispersed to see and we would expect the wind to blow it back onto the trailing officers at 18-23 mph. I don’t know if that happened, but it sounds reasonable. Maybe the bloody spray immediately dived into the ground like a lead ball, but I suspect it would stay suspended in the air for a second, long enough for the officers to drive through it.

But let’s not continue to go off on tangents, on bloody spray, jet-effect hypothesis, what was said fifty years ago, etc.

Questions:

Why was Dr. Zachanko kept in ignorance of film of the goat?

Why was Dr. Zachanko kept in ignorance of the William Hoffman study?

In the future, would you make certain a medical expert was made aware of my three points when you ask them if the neuro-muscular reaction hypothesis could be true?

When to you expect the CTers will find a single doctor, in the world, he knows about the three points I listed and still rejects the neuro-muscular reaction hypothesis? It’s been over 50 years. Do you think this will ever happen?


Whoosh. . . .  A few points in reply:

Dr. Zacharko was not "kept in ignorance" about anything. I didn't mention to him all the war footage that shows bodies traveling in the same direction as that of the striking bullet, either. I didn't mention that the bullet that struck Connally knocked him forward, and that Connally said it felt like someone hit him hard in the back with their fist. Why don't you deal with Dr. Zacharko's answer instead of this diversionary line of questioning?

It is a little silly to claim that Dr. Zacharko's answer was "based on ignorance" because I didn't mention an irrelevant goat film. I notice you did not address Dr. Riley's point that the neurobiology and neurophysics of a goat are completely different from that of a human.

I notice you didn't address Dr. Thompson's arguments against the neuro-muscular reaction theory, either. Without that theory, you have no way to explain the incredible speed of the opposing movements unless you allow for a shot from the front.

To excuse Dan Rather's description of the head movement as a memory mistake seems weak and strained. He had just watched the film a few hours earlier. His description of Connally's reaction is accurate. His description of when the film started matches what Zapruder himself said. His description of the head movement was the movement seen on the original film. Rather would not have mistaken a violent backward movement for a violent forward movement. DeLoach saw the same violent forward movement in the version (the original) that he saw. Bill Newman and several other witnesses likewise reported that sharp forward movement.

Posner's theory that the wind blew the particulate matter at Hargis with such force that he thought he'd been hit is ridiculous. The current Z film shows no spray blowing backward (it blows to the right front, toward the camera, and then, remarkably, disappears in a few frames). The wind that day was not continuous but was blowing intermittently. The limo's windshield and roll bar would have blocked much of the wind from blowing the spray backward anyway.

You said, "That initially, the head moved forward 2.3 inches between two Zapruder frames. Then it moved back." Uh, yeah, I made that exact point. And your only explanation for this amazing reversal of motion is the neuro-muscular reaction theory, a theory that even some of your fellow lone-gunman theorists reject, which is why they've opted for the jet-effect theory.

You said, "From z313 through z318, over a quarter of a second period, it accelerated from 0.0 mph to 1.9 mph. 2 mph is not being moved violently." LOL!  Seriously?!!!  So a 190% increase in speed in five frames on an object that has moved 2.3 inches in 1/18th of a second does not meet your definition of "violent"?!  And leaving aside this nonsensical denial, has it just been a while since you watched the Zapruder film?  I have never known anyone who claims that the backward movement of JFK's head in the film is not violent and dramatic. Not only does does his head move violently backward, but his torso is also thrown backward with considerable--obvious--force. 








Online Joe Elliott

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Re: A Question About Dr. Robert Zacharko.
« Reply #8 on: June 25, 2020, 12:17:44 AM »

Dr. Zacharko was not "kept in ignorance" about anything.

False. He was kept in ignorance of the main piece of evidence that LNers always bring forward when arguing for the Neuromuscular Spasm Hypothesis. The film of the goat being shot through the brain.



I didn't mention to him all the war footage that shows bodies traveling in the same direction as that of the striking bullet, either. I didn't mention that the bullet that struck Connally knocked him forward, and that Connally said it felt like someone hit him hard in the back with their fist. Why don't you deal with Dr. Zacharko's answer instead of this diversionary line of questioning?

You’re still playing the same game. Only mentioning films that show bodies falling away from the shooters. How about mentioning films were the bodies fall toward the shooters. Like the Holocaust film from Liepaja, Latvia, taken in the summer of 1941:


The amount of momentum in a bullet weighing a third of an ounce, going 1,400 mph, contains the same amount of momentum that a 28-pound weight has going 1 mph. And only about half or less of the momentum gets transferred since a rifle bullet typically exits a body with half or more off its speed. That is why some of the victims of this massacre fell toward the shooters, others away.

Look at the Mythbusters videos of targets weighing the same a human being struck by many types of bullets, including rifle bullets. The experiments match what simple calculations, like the one I provided, say. Not a lot of momentum is transferred, because bullets only have a small amount of momentum. They don’t fling bodies around violently, or even at 2 mph.

A soldier shot in combat might start moving quickly in certain directions just before getting hit, might start to flinch away from gunflashes. Giving the false impression that they were being flung about by bullets.

Tests with a ballistic gel target, like the Myth Busters use, are a better test because ballistic gel targets don’t’ flinch away from gunfire.



It is a little silly to claim that Dr. Zacharko's answer was "based on ignorance" because I didn't mention an irrelevant goat film. I notice you did not address Dr. Riley's point that the neurobiology and neurophysics of a goat are completely different from that of a human.

You claim the goat film is irrelevant.

Can you support your unfounded claim? This unfounded excuse not to inform Dr. Zacharko of the existence of this film? That is:

Question 1:
Can you name a single article, a single book, that argues for the Neuromuscular Spasm as being the cause of JFK’s backward movement, that does not even mention the film of the goat?


If not, then this is not an irrelevant fact, but core of the claim of the Neuromuscular Spasm Hypothesis and should have been mentioned to Dr. Zacharko before asking for this opinion, since this might have altered his conclusions.



Question 2:
Should an authority be informed of the main argument, the main piece of evidence, of both sides before being asked for his opinion? Yes or No.


Or is it sometimes best to keep him in ignorance.



Question 3:
Should the decision to dismiss the main piece of evidence presented by LNers, be made by Dr. Zacharko or Michael Griffith?




I notice you didn't address Dr. Thompson's arguments against the neuro-muscular reaction theory, either. Without that theory, you have no way to explain the incredible speed of the opposing movements unless you allow for a shot from the front.

Doctor Thompson, is it? Are you trying to give the false impression that you do have a medical doctor who knows about the goat film and whose medical expertise leaves him to not believe in the Neuromuscular Spasm? Josiah Thompson has a Ph.D. in Philosophy, not in medicine. Again, you phrase things that are technically correct, but misleading.

So, what does our good “doctor” has to say:

Quote
The extremely small time factor combined with the relatively large mass of the President's head would tend to rule out such an explanation. The fastest reflex action known to science--the startle response--takes place over an interval of 40 to 200 milliseconds. Beginning with an eyeblink in 40 milliseconds, the response wave moves the head forward in 83 milliseconds, and then continues downward reaching the knees in 200 milliseconds. The change in direction we observe [i.e., the change from the forward motion of JFK's head to the more violent rearward motion] occurs in 56 milliseconds (1/18th second), and involves not the negligible mass of an eyelid but the considerable mass of a human head moving forward under an acceleration of several g's.

Interesting. Except the goat started moving its body 40 milliseconds after being shot. And not with an eye blink. So, regardless of the opinion of “Doctor” Thompson, the Neuromuscular Spasm can start within 55 ms, or indeed, withing 40ms.



To excuse Dan Rather's description of the head movement as a memory mistake seems weak and strained. He had just watched the film a few hours earlier. His description of Connally's reaction is accurate. His description of when the film started matches what Zapruder himself said. His description of the head movement was the movement seen on the original film. Rather would not have mistaken a violent backward movement for a violent forward movement. DeLoach saw the same violent forward movement in the version (the original) that he saw. Bill Newman and several other witnesses likewise reported that sharp forward movement.

Witness are often in error when interviewed within a few hours, or even immediately. They may remember somethings right and somethings wrong. Can you prove that Dan Rather had an infallible photographic memory? Or name any person in the world with an infallible photographic memory?



Posner's theory that the wind blew the particulate matter at Hargis with such force that he thought he'd been hit is ridiculous. The current Z film shows no spray blowing backward (it blows to the right front, toward the camera, and then, remarkably, disappears in a few frames). The wind that day was not continuous but was blowing intermittently. The limo's windshield and roll bar would have blocked much of the wind from blowing the spray backward anyway.

Again, you are being misleading. Hargis never said that he was hit with such force he thought he had been hit. Only CTers said that.

He only said he felt something hit his face and thought he was shot. He doesn’t say it was the force of the object that convinced him he was shot. It could be he saw the head explode, felt something touch him and thought he was struck. And how much force could he been struck with and still leave him unwounded?



You said, "That initially, the head moved forward 2.3 inches between two Zapruder frames. Then it moved back." Uh, yeah, I made that exact point. And your only explanation for this amazing reversal of motion is the neuro-muscular reaction theory, a theory that even some of your fellow lone-gunman theorists reject, which is why they've opted for the jet-effect theory.

Not all LNers are right about everything. I’m sure some of my current beliefs about the assassination will change in the future, as they have in the past.



You said, "From z313 through z318, over a quarter of a second period, it accelerated from 0.0 mph to 1.9 mph. 2 mph is not being moved violently." LOL!  Seriously?!!!  So a 190% increase in speed in five frames on an object that has moved 2.3 inches in 1/18th of a second does not meet your definition of "violent"?!  And leaving aside this nonsensical denial, has it just been a while since you watched the Zapruder film?  I have never known anyone who claims that the backward movement of JFK's head in the film is not violent and dramatic. Not only does does his head move violently backward, but his torso is also thrown backward with considerable--obvious--force.

No, it’s not a 190% increase. It is an infinite amount of increase, from 0 mph to 2 mph. But it doesn’t matter, a 190% increase or an infinite amount of increase, is still only an increase of 2 mph. If this is violent movement than every time, I walk through the neighborhood I do so with a violent amount of speed. I’m liable to break someone’s ribs if I bump into them.

If you say to someone: JFK’s head was very violently thrown backwards. Could this be the result of a Neuromuscular Spasm? Your average person will answer no. How could the human body be capable of such violent movement?

But if you say to someone: JFK’s head moved backwards, over a time of a quarter of a second, from 0 mph to 2 mph. Could this be the result of a Neuromuscular Spasm? Your average person will be more inclined not to dismiss the Neuromuscular Spasm Hypothesis out of hand.


Question 4:

In the future, will you tell people that JFK’s head was thrown back violently, or tell them it moved backwards at 2 mph?



Question 5:

And the most important question of all. Do you believe a bullet only transfers momentum to a target while it is passing through the target?

Or do you believe a bullet can continue to transfer momentum to a target even after it’s left the body. Accounting for the gradual increase of speed of JFK’s backwards from 0 mph to 2 mph over the course of a quarter of a second.




I’m going to keep asking questions 1 through 5 until you answer them.

Offline Michael T. Griffith

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Re: A Question About Dr. Robert Zacharko.
« Reply #9 on: June 25, 2020, 01:13:56 AM »
Dr. David Mantik, who is both a physicist and a medical doctor (radiation oncology), explains some of the problems with the neuromuscular reaction theory:

Quote
The other traditional explanation for the head snap has been the "neuromuscular reaction." This was first proposed to the HSCA not by any neuroscience specialist, but by a wound ballistics expert based on his viewing old films of goats being shot in the head. To date no official testimony has been obtained from appropriate specialists (the neuroscientists) on this question. At the very least, interspecies differences in neurophysiology would leave this conclusion open at least to some doubt. In addition, the usual reaction to such brain trauma is not the highly directed movement observed in the Zapruder film but rather random muscular activity. Even Alvarez concluded that the highly directional recoil seen in the Zapruder film required the application of an external force.

Yet another objection to the decerebrate rigidity invoked by the HSCA is the time of onset; even the HSCA admitted that this would develop only after several minutes. I have been unable to find any literature references that even hint that this reaction could occur within milliseconds in human subjects-as is required for the head snap as seen in the film. Furthermore, in a large collaborative study (A.E. Walker, Cerebral Death, 1981, p. 33) with over 500 patients who experienced cerebral death, 70% were limp when observed just before death and an additional 10% became limp at about the time of death. At the very least, therefore, based on all of these considerations, the attempt by the HSCA to implicate a neuromuscular reaction is open to serious doubt. Moreover, the minimum requirement has never been met-the appropriate experts have never been officially consulted.

An additional argument against a neuromuscular reaction is that the observed reaction in the film is much too fast to fit with such a reflex. By the analysis of more than one study, within the space of one Zapruder frame interval (55 msec), the head clearly moves backward. Typical human reflex times are 114 to 112 second (250 to 500 msec). This is an extraordinary discrepancy-a factor of 5 to 10, which, all by itself, makes this scenario quite unlikely. (Assassination Science, pp. 281-282, PDF copy available online at https://www.krusch.com/books/kennedy/Assassination_Science.pdf)
« Last Edit: June 25, 2020, 01:14:40 AM by Michael T. Griffith »

 

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