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Vaulting heel drive...

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blantonnick

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Ask any gymnast or coach 'when does heel drive start on vault?' and the majority would say from the springboard to the vault table. In other words, once the feet contact the springboard the heels are driven upwards over the center of mass to facilitate rotation. I would challenge this answer in that I believe heel drive should start before the feet contact the springboard, during the hurdle phase. This process is very quick, allows for explosive compression of the springboard, which in turn will facilitate a stronger heel drive in the end. Any thoughts or disagreements?
 

Geoffrey Taucer

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I think in the case of vault, the term "heel drive" is not as accurate as it could be.

If we take "heel drive" to mean a tight arch (which is how I would normally interperet the phrase), it does not start until after the feet leave the springboard. If you snap to a tight arch when your feet are still on the springboard, it rotates you in entirely the wrong direction, the opposite of what a heel drive is intended to accomplish. What you have to do (and I don't actually tell kids to do this, because they tend exaggerate it if they try to do in intentionally) is a snap to hollow with the feet on the board, and then a snap to a tight arch right after they come off.

So the process of generating rotation starts as soon as the feet contact the board, but the snap to a tight arch occurs just after the feet leave the board.
 

blantonnick

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Just recently had a National Coach come back from a FIG conference where a lecture was performed by one of the Canadian National Coaches Edouard Iarov. A new trend is emerging and being recognized in advanced level vaulting to emphasize the hips being raised off the springboard then initiating a heel drive...quite an interesting concept, and one that is very evident when you look at Alicia Sacromone's Front Handspring Front 3/2.
However, aside from that, I think your comments are very valid in the context that you put them. Very good points.
It would seem that the heels being thrustfully driven into the board was the idea that I was referring to when driving the heels before they contact on the board.
 

Valentin

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I would have to say, i am definitely with the majority on this haha..

Biomechanicaly speaking, you can't generate any torque (rotation)without and eccentric force (one that doesn't pass through the center of mass).That being said it means that for the body to be rotating on take-off from the board the center of mass (so roughly the belly button). So regardless of when you start heel driving, without this there is 0 rotation.

No why do i think you have to heel drive as you push of the board.
1- Heel drive is really a leg drive, which is done mainly by the hip extensors, that is the butt muscles, hamstrings, and knee extensors (quads)
2- When you impact the board the knees bend and the hips flex a little

thus it means that as you impact the board you have to use the hip and knee extensors and quads to push on the board and extend the knees and hips to take off. If on the take off you are floopy, this strong fast/explosive push/rebound is not very effective. The tighter the better. THis can be demonstrated by the stick test.. If you throw a stick at a stick on a anglebut you throw it so that only one tip hits, given that its throw hard enough it will flip over its end..like in a vault take off-layout.

Thus saying that you heel drive before impact it means that you are hitting the board with straight legs, and open hips. which is just not efficient way to generate any kind of roation or explosive push of the board.

The heel drive in my opinio based on these facts occurs from the take-off.


Valentin

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blantonnick

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Let me take a second to clarify what the concept is because possibly the idea of heel drive is being confused...
Using the stick test as you did Valentin is a great way to illustrate what I was referring to. By throwing the stick forward, you the thrower, are in essence creating a heel drive by throwing the stick so that rotation begins from the second the stick leaves your hand. This rotation allows the stick to rotate such that once its impact occurs on the floor (feet contact the springboard) the transfer of energy from the stress on the floor to the stick generates maximal rotational forces forward from where the stick contacts the floor. This happens because as the stick contacts the floor the top (the other side of the stick, up in the air) of the stick is thrusted forward by a transfer of energy (the upper body rotates forward and the hands are reach towards the table).
That being stated (as confusing as it may be) the transfer of energy forward from the feet on the board, to the vault table, I believe happens just prior to the feet contacting the springboard. The idea is for the gymnast to produce 'that throwing of the stick towards the floor' as stated above.
The idea was not to imply that an arch is performed onto the springboard as pointed out ( that would actually be dangerous if performed at full speed). Heel drive in the case that I am referring to is actually the idea of thrusting the feet downwards into the board in such a direction that the upper extremeties of the body are thrusted forward (just as the stick was thrusted forward on the floor) allowing for less time from the feet leaving the board to the hands contacting the table.
Please keep up the reply as this seems to be a nice topic to chat about...
 

Valentin

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Hello

I have to be honest i think that i am really confused now about what you refer to heel drive.
Lets first clarify some of the biomechanics here, because it seems to me that you are confusing it, or applying it incorrectly.

First.. Throwing the stick actually does not generate rotation (well it should not if we could throw the in a way such as hurdle).

" By throwing the stick forward, you the thrower, are in essence creating a heel drive by throwing the stick so that rotation begins from the second the stick leaves your hand'

This is not true. When the thrower, throws the stick, they are imparting linear momentum to the stick in a specified direction which should be at something like 60deg for the stick test to work well. There is NO rotation, otherwise the stick will be rotating in the air before it hits the floor which it does not. It just flys ina straight line at a 60 angle downward towards the floor. Of course this is the resultant momentum vector, which is the result of a horizontal and vertical (downward) momentum. Meaning that the stick is moving forward and downward.

"rotation allows the stick to rotate such that once its impact occurs on the floor (feet contact the springboard) the transfer of energy from the stress on the floor to the stick generates maximal rotational forces forward from where the stick contacts the floor. This happens because as the stick contacts the floor the top (the other side of the stick, up in the air) of the stick is thrusted forward by a transfer of energy (the upper body rotates forward and the hands are reach towards the table)"

This is not entirely correct. When the stick impacts the floor, yes there is a action reaction pushing the stick back at a 60deg angle back towards where it came from, but because there is also a horizontal momentum, and the rebound of the floor is not instanenous (even though it may appear that way, because the eyes cant see at 2500 frames per second..haha... I WISH!!!).. and what we dont see is that as the stick ins going down and compressing the foam top of the floor (the stick test dont work on concrete very well haha)..it is also moving at a constant forward velocity (due to that horizontal momentum). By the time the ground vertical donward force (momentum) of the stick is attenuated, stoped, and then the ground reaction force pushes the stick back, ideal the stick should have rotated over the point of impact to about a 30deg-45deg (approximately). This is know as the centrifugal force. When the ground reaction force eventually pushes back on the stick the force doesnt pass through the center of mass of the stick, and thus produces a torgue.

One thing that you are not taking into account when you compare the stick example and the body is that the body is far! from rigid like a stick and thus the actual forces that take place are more complicated and always changing due to muscular effort and point of force application of the feet. The stick example only roughly illustrates the point that for the gymnast to get a good first flight they need to hit the board with the center of mass behind the feet...so that while the board springs are compressing the body rotates over the feet. When this happens the center of mass should ideal be as high as possible, and thus only about 30deg infront of the feet.

"transfer of energy forward from the feet on the board, to the vault table, I believe happens just prior to the feet contacting the springboard."

This is impossible... I am sorry but how can you tranfer energy without even being in contact with the object?? Think about what you are saying.. you are in the air flying towards the board and you are tranfering energy somehow to the table..it makes no sense. You need to rethink this..


For a bette explanation of how the vaulting works and why i say what i say please read the article i wrote on vaulting for The Gym Press newsletter from
- July Issue of the Gym Press

Valentin
The Gym Press Blog
 

blantonnick

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Very educational, thanks...

Let me clarify, are you throwing the stick like a javelin at the floor? if this is the case then yes i agree with you. However, I am interpreting you are thrusting the stick at the floor by holding the very bottom and allowing it to flip end over end to contact the floor...if that is the case then i must disagree with you...please clarify..

The other issue I would like to raise is regarding this comment...
'for the gymnast to get a good first flight they need to hit the board with the center of mass behind the feet'
I must agree maybe with younger gymnasts this may be the case. However, at advanced levels I believe you are greatly encouraging a loss of power by instructing a gymnast to place his center of mass behind his or her feet. By instructing this you are encouraging the gymnast to lean backwards on the springboard. This I believe is very detrimental to an effective hit on the board. The board is sloped so that the center of mass does not have to lean backwards to get an effective strike/compression of the springs on contact. If the springboard were flat as the floor is, then yes lean backwards. However, the shape of the board allows for the center of mass to be directly positioned over the feet for a dynamic and effective strike....please elaborate on the reasoning behind COM behind the feet...
Thanks
Nick
 

Valentin

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Hi Nick

"Let me clarify, are you throwing the stick like a javelin at the floor"
Yeah totaly. I would not throw the stick by holding the very bottom and allowing it to flip end over end to contact the floor, because this would imply that as the gymnast is jumping toward the spring board he/she is flipping and has a certain degree of rotational velocity. This however is obviosuly not true, because the gymnast is not rotation in the air, but rather following a parabolic flight curve from the floor to the board.

"please elaborate on the reasoning behind COM behind the feet..."
The reasoning behind it is, in order to allow the gymnast compression time of the board, and a take-off that optimises a vertical take off. The slopped is to maximise this. Here is a good photo of illustating what i am saying.


As you can see there is virtually no slope... Also the design on the board requires it to be sloped because
1- it reduces the risk of gymnast cliping feet as they hurdle
2- It allow the gymnast to enter the spring board long and low.
3- Stability

From studies on the worlds best vaulters, its actually been clearly be reported that they have a lean of about 30deg backward on impact of the baord. This being 1 key variable separating the great vaulters from the others.
But dont take my word for it here are 2 references to this.
1. Cuk I., Karacsony I. (2004). Vault : Methods,Ideas, Curiosities, History. Tiskarna Ljubljana: Slovenia. STD Sangvincki
2. Smith. T (1984).Gymnastics: A mechanical understanding. Holmes & Meier Publishers, Inc. New York.
3. Prassas, S. (2001).Vaulting Mechanics. [/SIZE][/FONT][SIZE=2][COLOR=#0000ff][URL]http://www.coachesinfo.com/category/gymnastics/315/[/COLOR]


 

blantonnick

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I tried to find both the abstracts you referred to however, were not able to locate them on the internet. However, I must ask you, do you advocate then instructing gymnasts to lean backwards on the springboard? I think sometime biomechanics and actual coaching can conflict greatly. For instance, keeping the head tucked in on a dismount off the high bar is something we all advocate for safety reasons when first learning, however, biomechanically speaking it actually will decrease angular momentum about the longitudinal axis...
 

Geoffrey Taucer

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I consider leaning back when you hit the springboard to be one of the hardest -- but most important -- things to teach beginning vaulters.
 

Valentin

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Hi

Its a shame about the coachesinfo website.. it seems to be down at the moment, i cant enter it either.
However i come prepared here is the article.
Prassas, S. (2001).Vaulting Mechanics.
You wont find the others because well they are books. The T.Smith one is from 1984 and i no longer sold, and the Cuk I., Karacsony I. (2004). Vault : Methods,Ideas, Curiosities, History is a book i got directly from Ivan Cuk, which was bloody nice of him if you ask me, and i have never seen it sold anywhere else. I have only seen their Rings books on http://www.gripsetc.com/store/shopexd.asp?id=879

"do you advocate then instructing gymnasts to lean backwards on the springboard"
Not really. I encourage hitting the board so that the feet are infront onf the knees, and the knees infront of the shoulders. Essentially that is leaning back, but i dont tell them that. I try and stress a proper hurdle and bringing the legs fast infront of the body without letting the front leg drop. Watch your gymnasts closely i am 99% sure that when they hurdle and the stretch their dominant leg forward before they actually hit the board their feet pull back (as i call it drop) so that they can feel that they will land in a stable position, which is not what we want, especially as that means they knees will generaly go infront of the knees before take off.
I dont say lean back on the board (even though i guess you could say that). I try to focus more on entry (hurdle) being long and low, with the hip remaining at a close to constant height during the hurdle rather then a jump/stomp ontop of the board.

I would also agree with Geoffrey Taucer teh correct entry onto the board is one of the hardest and most under coaches areas of vault in my opinion. Its especially important for beginers.

"think sometime biomechanics and actual coaching can conflict greatly think sometime biomechanics and actual coaching can conflict greatly"
You are so right about that...the term being analysis to paralysis. However i do believe its important for coaches to have a basic biomechanics understanding of what they are asking their gymnats to do, as well as to be able to better analyse skills and understand why certain techniques might be better then others and when.


"For instance, keeping the head tucked in on a dismount off the high bar is something we all advocate for safety reasons when first learning, however, biomechanically speaking it actually will decrease angular momentum about the longitudinal axis"
Even though i total understand the reasoning and i totaly encourage safe techniqye and practices i think that this is not something that is mandatory. Reason is because you should be teaching the gymnast to push away from the bar at all times anyways and when teaching the flyaway if they have learned the progressions right then its not a problem. You are right however that tucking the head in against the direction of rotation, and the solution really is that you have to bring the body to the head so to speak, so that as the body is rotation towards the head there is a natural flexion of the neck. Doing so naturaly increaese angular rotation by reducing inertia and thus increasing angular velocity.

I personaly never find that i have to say anything to gymnasts that isnt biomechanically sound, even though i am sure there are probably cases where it might pay in order to make a point or as you say for safety. If anything i might say to change body shape which is an exagerate or far from idea, for them to feel something different, but that is about it (and i dont even think that is all that effective, but desperate times call for desperate measures haha).
 

blantonnick

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'If anything i might say to change body shape which is an exagerate or far from idea, for them to feel something different, but that is about it (and i dont even think that is all that effective, but desperate times call for desperate measures haha).'

I think that this reasoning you stated above is the reason for me originally stating the heel drive should start before the feet contact the springboard.
From a biomechanical standpoint I would agree with you, it is virtually impossible to safely perform a heel drive before the feet contact the springboard. I encourage gymnasts to anticipate this process by instructing them to begin driving their heels as the springs are compressing on the springboard, or just before contact. I am finding extremely good results with this process and would encourage others to examine this idea. By emphasising the gymnast slam his or her feet into the board (the idea of driving the heels into the board) I believe the anticipation allows gymnasts a better understanding and more powerful concept of heel drive...
Great posts though Valentin thanks...
 

blantonnick

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Valentin I would encourage you to check out the video on www.gymnasticscoaching.com to see Lu Bin's Front Handspring 2.5 twist on Vault. Pausing his position on contact to the spring board I believe will show you his upper torso region is, in line and even leaning over his feet on the springboard. It is vaults like this one that lead me to believe that the new table is encouraging the COM to be over the feet for advanced level vaulting rather then behind the feet as encouraged at the basic levels. The new table is changing the way vaulting biomechanics are looked at. It allows for lower contact of the hands on preflight, which in turn is allowing for the COM on springboard contact, to be leaning forward more towards being in line with the feet, rather then behind. I think the biomechanical literature needs to be examined and possibly updated due to the introduction of the table.

Prassas' article on Vaulting was published in 2001, the same year the Vaulting table was introduced in Ghent. I am not advocating that his literature is incorrect, as there are many techniques and biomechanical principles he addresses that are very important and educational. However, I would love to see a follow up study done, by him or anyone else, as to the effect the new table has had on the biomechanics of the springboard contact phase.

In my opinion, there seems to be a shift away from a previous thought important lean back phase on the board, as the pre flight on the new table does not need to be as high. This is due to two main reasons, the table is sloped and more importantly the table is springier (if that can be considered a word) than the old vaulting horse.
 

Valentin

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Interesting

The socratic method at work ladies and gentelman haha..

"I encourage gymnasts to anticipate this process by instructing them to begin driving their heels as the springs are compressing on the springboard, or just before contact"
Now this i can agree with. I do the same. I just tell them to begin the heel drive of the springboard instead. i guess the concept is the same. Yours is probably a better way of putting it, because i guess it gives them i guess more time to react haha.
"By emphasising the gymnast slam his or her feet into the board (the idea of driving the heels into the board) I believe the anticipation allows gymnasts a better understanding and more powerful concept of heel drive"
I agree with the concept its good. One thing that i would have a problem with is with actually telling the gymnast to slam the heels down, As entry should idealy by on a flat foot, to close to.. (this is actually a gray area to be honest, because there are certain advantages on flat foot entry and with on almost full planterflexted feet. No matter what the ankles need to be held tight on impact. But in short concept is good and i shall tell my gymnasts from now on to try and anticipate the heel drive. I like the idea. I guess the common term coaches use is ...punch of the board, which i guess is teh same thing, but what you say is more specific i like that better.

"Lu Bin's Front Handspring 2.5 twist on Vault. Pausing his position on contact to the spring board I believe will show you his upper torso region is, in line and even leaning over his feet on the springboard."
You are right and actually everyone will see virtually all gymnasts leaning forward over their feet a little. Key consideration when we analyse video like this is to watch out and remember that
Cameras used have a Low frame rate and detail of video is shocking (thanks you tube haha). Becasue most cameras work at 25fps we actually dont always (hardly ever actually) see the real moment of impact which is vital for proper analysis, becase ms do matter here. Video quality is shocking (as you can see) and its not a proper side on view so there is prespective error
http://www.imagehosting.com/show.php/1425932_LiuBinentryonvault.jpg.html
I did a very very very rough little drawing showing you that actually on impact and this is actually much past the moment of impact as the board is quite depressed at this stage, his center of mass is behind his feet at a about a 30deg angle from the point of impact.
His upper body is also virtually almost upright, it probably was on impact istant aka 30deg leaning back. As you can see he is showing all the KEY points of a good vaulter
1- Entry being with center of mass behind point of impact at around 30deg.
2- Upper body is very upright
3- He will leave with the cente of mass relatively high,
4- Arms reaching forward hard!! which will ensure a nice fast first contact with the table 4
5- You can tell that his turnover prior to first contact will be FAST! look at the video its just awesomely fast.
6- HEAPS!!! of horizontal momentum.

"In my opinion, there seems to be a shift away from a previous thought important lean back phase on the board, as the pre flight on the new table does not need to be as high."
I have to disagree here. I dont think the table has changed the springboard mechanics a lot. Not for me anyways at least. The table has only optimised male performance due to arms being able to be a little wider and thus optimise the block resultant force (due to anatomical advange of arm position).
For women it has a huge effect because since the table is three times wider then the old horse meaning that women need to try and have a technique that slightly favours going for distance then height.. which is a limitation to womens vaulting (this is because women are in general weaker, smaller, slower etc..)

The pre-flight has always! be emphasised to be low. At a younger age gymnasts should come on a little higher because its easier for the to get over, and to block, because using a more advanced technique requires strength strength strength and power and power and even more power.
If you looked at the vaulting technique of Marian Dragulescu pre 2001 and post you will see its the same in general but he able to get more height of the table the then the horse.
1- Beacause of the slight slight slight slope,
2- Springiness (i think that is word or it should be haha).

I agree with you that someone should do a follow up study. Ivan Cuk, however did all his stuff (analysis with the table and not the horse, and pretty much everything for the horse is still valid (for MAG anyways).

Nik brilliant discussion..thank you. i am learning here..always a pleasure
 

blantonnick

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'The socratic method at work ladies and gentelman haha.. '

Haha yes but Valentin no one wants to win here, no ego involved...we just want to examine and find out for ourselves (well ultimately our gymnasts) what we believe to be correct.:)

Some of the issues raised were brilliant and have caused us to question what we teach (at least they did for me). I would love to engage in some more questions with you in the future!

One such question that has plagued me for some time, still on the Vaulting event, would be regarding Yurchenko's:
Do you teach Yurchenko's by beginning with a backwards flick (backhandspring) and move higher...or do you advocate beginning with a high straight back and moving lower? Better yet a mixture of both? any feelings?
This is all assuming work has already been done on the Roundoff entry...
 

Valentin

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Hi Nik

You are right, i am sorry i didnt mean it like that."no ego involved"
None at all, as a matter of fact i think its absolutely ignorant and a bad coaching trait not to want to explore alternative methods. To many coaches just stick to what they know and never branch out, or try anything different. Its either their way or the highway you know. I am glad that internet provides a forum where people can actually share ideas and learn from one another. Like i have from you, like you said "Some of the issues raised were brilliant and have caused us to question what we teach", totaly agree.

I actually have never coaches a Yurchenko. Its a vault that i have not researched a lot simply because well its not something i have had the pleasure to coach. I start on it once with a few of the gymnasts but i had to leave the club before we got any further then round-offs onto the board.
However, from what i do know, i would say i would definitely insit on 2 things
1- A ReaLLLLLY strong standing back handspring
2- A layout over a table height from a spring board.
As you said if the round-off entry is good/perfected (which i would say is key, and probably better time investment to perfect over just learning to throw a vault), i would do a mixture of the two.
I would work on doing layouts onto mats at least vault height, and also work on the block of action learning to lift the shoudlers and not snap the feet down.

I say this because recently i was working at a top club in the US (California) and head coach teaught his gymnasts to do the back handspring first, and did no layout stuff at all. All his gymansts had closing shoulders actions on the vault table, and could not reach back with open shoulder.
I would spend HEAPS!! of time drill in how to take-off and reach back to open the shoulder angle.
 

ACoach78

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I say this because recently i was working at a top club in the US (California) and head coach teaught his gymnasts to do the back handspring first, and did no layout stuff at all. All his gymansts had closing shoulders actions on the vault table, and could not reach back with open shoulder.
I would spend HEAPS!! of time drill in how to take-off and reach back to open the shoulder angle.
This sounds more like an issue of a coach who's sending the kids over the table way too soon. A good coach will back these kids up and correct those issues. But, it sounds like they're probably nervous about what they're doing and they're changing their technique so as to insure that they feel safer.

I tend to prefer to teach it from a RO BHS because I want the kids to really learn the rhythm of the skill. Teaching the skill as a double layout in which you touch your hands works well for the really powerful kids because frankly, I think that most anything will work for them. However, with the less powerful kids, I'm not sure that you'll be able to get a very good layout off of the board. Plus, to me, you're ingraining how to come on high onto the table. I'd rather be more patient and gradually build the RO BHS up to a higher and higher level.

With that said, I still like to do RO double backs/layouts and such into the pit for air awareness purposes.
 

Valentin

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ACoach78 i can't speak for that coach, and why he does what he does, but i would agree that the kids are made/asked to learn the vault very early on. From what i observed when i was there, most go from the handspring (and it doesn't even have to be a great looking handspring) straight to the Yurchenkos. However thinking about it, these are the kids who were selected for TOPS and made the selection. Do you know why he might do that, is there something in the TOPS program that requires kids to do Yurchenkos?

I like your call about the double layout...i can see the logic, and i totaly agree, with the powerfull ones almost anything will work haha..so sad. Actually i would say that is why we see so many different techniques used, cause the powerfull ones get lazy, and the caoches say...stuff it it works lets not mess with it, lets just try and add another twist or whatever.

With the less powerfull kids my priorities will definitely lie in coming on a little higher. reason behind that (and it can be argued both ways), is that if they can block of the table with the center of mass already a little higher it will/ could make up for lack of power. However that being said it does require power to be able to do this, and thus it is a catch 22, so conditioning and preparation (specific) would be a major factor.
 
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