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ashita

The close to impossible : crazy move

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Joshua Slocum

Forgetting for a second about left/right, and forgetting about crosses, we have two dimensions: forward/backwards, and up/down. Given that gravity always points down, the torque on a joint is equal to the product of the distance along the forward/backwards axis from the joint to your center of mass, times your weight (minus arms). Since your bodyweight doesn't change across skills, the critical factor is the distance from your hips to

So for a back lever, the amount of torque that your shoulders must support is [approximately] equal to the distance from your hips to your shoulders, times your bodyweight (minus your arms). This figure is the same for front levers, malteses, planches and victorians. The varying difficulty of those skills is due to varying biomechanical advantage.

For the 'bad front lever' the torque is reduced, because the hips are closer to the shoulders along the front/back axis. Note that this means the torque for the CTI is in fact zero. This may seem counter-intuitive at first. To see how this works, imagine you were to weld two steel girders to a bar sticking straight out, parallel to the floor. If you were to rest the girders in your armpits, you wouldn't start to rotate: you'd just hang straight down. If your arms were strong enough to replace the steel girders, your torso would dangle in the same fashion from your shoulder joints.

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alec_ar

Thanks for the detailed reply bro. I really appreciate it, and understand it a little better I think ;)

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Rob Kowalski

Forgetting for a second about left/right, and forgetting about crosses, we have two dimensions: forward/backwards, and up/down. Given that gravity always points down, the torque on a joint is equal to the product of the distance along the forward/backwards axis from the joint to your center of mass, times your weight (minus arms). Since your bodyweight doesn't change across skills, the critical factor is the distance from your hips to

So for a back lever, the amount of torque that your shoulders must support is [approximately] equal to the distance from your hips to your shoulders, times your bodyweight (minus your arms). This figure is the same for front levers, malteses, planches and victorians. The varying difficulty of those skills is due to varying biomechanical advantage.

For the 'bad front lever' the torque is reduced, because the hips are closer to the shoulders along the front/back axis. Note that this means the torque for the CTI is in fact zero. This may seem counter-intuitive at first. To see how this works, imagine you were to weld two steel girders to a bar sticking straight out, parallel to the floor. If you were to rest the girders in your armpits, you wouldn't start to rotate: you'd just hang straight down. If your arms were strong enough to replace the steel girders, your torso would dangle in the same fashion from your shoulder joints.

That makes total sense. Thanks for the clear explanation. How would you calculate the torque required on the wrist for the CTI?

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Joshua Naterman

It is a lot more complicated than that, I mean it's not a huge deal to calculate a fairly reasonable external torque but internal torque is what matters here and that's extremely complicated.

You have to look at relative positions of the gravity acceleration vector and force-producing vectors of the muscles involved so that you can see which muscles can contribute force and which ones cannot, and to what degree this changes. Like I said, very complicated.

External torque and internal torque are completely different.

Your hips are irrelevant to your torque. Your center of mass is what matters, and that changes with every movement you make. To find where it is, you will need to assume the exact body posture of the movement and then balance on a small beam on your stomach or back. When you find the balance point with that posture, you will be able to make an approximate measurement from that spot to the shoulder. You TO be truly accurate you will need to know whether the CoM is inside the body or out, in other words you need the x, y AND z coordinates of the CoM. Once you've got that, you plot those and then plot the shoulder, and then the elbows and hand contact point. NOW you can start doing vector analysis and figure out what the external torque requirement is.

For internal torque, meaning actual muscle force production and distribution, you have to figure out exactly how much force each muscle is producing, the direction of force application, and then resolve these into a total. This is very, very very complicated which is why it is basically never done. You have to do PCSA, then compare baseline EMG to MVC EMG, then start plotting all the attachment points and bones, and the relative contribution of different fiber groups within multipennate muscles like pecs, deltoids, lats and traps. You have to adjust for tendon compliance, and so on.

With multivariable calculus this can be done, but it is a whole lot of work and the attachment points are just going to be guesses based on palpations where possible and anatomical averages from cadaver studies. Maybe MRI can be used, but unless you have a WHOLE lot of money that's irrelevant, and unnecessary exposure to powerful energy fields is an uncalled for health risk.

By analyzing this way you can actually figure out which muscles aren't contributing what they are supposed to so that you know what to specifically work on.

This has been done at the Shepherd Spine Center in some research for spinal cord injury rehab purposes. It is intensely academic.

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Joshua Slocum

It is a lot more complicated than that, I mean it's not a huge deal to calculate a fairly reasonable external torque but internal torque is what matters here and that's extremely complicated.

You have to look at relative positions of the gravity acceleration vector and force-producing vectors of the muscles involved so that you can see which muscles can contribute force and which ones cannot, and to what degree this changes. Like I said, very complicated.

No, you don't. If you want to know the torque being applied about the shoulder joint, you don't need to know anything about the muscles. You need to know where the center of mass is, where the fulcrum is, where the support is, and which way gravity is. If you want to know how much contractile force the muscles must exert, that is a different story.

External torque and internal torque are completely different.

I'm not a kinestesiologist, so I don't know the precise definitions of 'external torque' and 'internal torque.' If you could elaborate further on what you mean by the two terms I'd be curious to know what the difference is.

Your hips are irrelevant to your torque. Your center of mass is what matters, and that changes with every movement you make. To find where it is, you will need to assume the exact body posture of the movement and then balance on a small beam on your stomach or back. When you find the balance point with that posture, you will be able to make an approximate measurement from that spot to the shoulder. You TO be truly accurate you will need to know whether the CoM is inside the body or out, in other words you need the x, y AND z coordinates of the CoM. Once you've got that, you plot those and then plot the shoulder, and then the elbows and hand contact point. NOW you can start doing vector analysis and figure out what the external torque requirement is.

Yeah, or you could just note that hips tend to be a reasonable back-of-the-napkin estimate for your center of mass when in a laid out position and use that to get a first-order approximation. Also note that since we're dealing with torque about the shoulders, the arms and the body have to be considered separately.

For internal torque, meaning actual muscle force production and distribution, you have to figure out exactly how much force each muscle is producing, the direction of force application, and then resolve these into a total.

*snip*

That sounds like a pretty awesome process, but it's completely unnecessary here. The torque exerted on the shoulder by the weight of the body is negligible, therefore the muscular forces required to maintain that shoulder position will also be negligible.

Also, you're mixing units. Torque is not force. Units of torque measure mass*distance/time^2, whereas unites of force measure mass/time^2. Torque is a measure of how strongly something is being rotated, and force is a measure of how strongly something is being pushed.

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Rik de Kort
Yeah, or you could just note that hips tend to be a reasonable back-of-the-napkin estimate for your center of mass when in a laid out position and use that to get a first-order approximation. Also note that since we're dealing with torque about the shoulders, the arms and the body have to be considered separately.

Actually you can't really consider them seperately because some muscles cross mutliple joints. Good examples are the biceps and triceps, which cross both the elbow and the shoulder.

There are some theorems in mathematics that may make this a whole lot easier, though. So if we were to do a complete analysis of all factors involved, we could get a reasonable approximation that requires less calculation given certain circumstances (small ranges for muscle/tendon length and such).

Also, you're mixing units. Torque is not force. Torque is mass*distance/seconds^2, whereas force is mass/seconds^2. Torque is a measure of how strongly something is being rotated, and force is a measure of how strongly something is being pushed.

Torque is what matters during movement. The muscles produce force, but there is a lever system involved, so if you want to talk about 'force production' at a joint, you are talking about something imaginary, as the amount of force produced by the joint varies with the lever length of the load. If you put weight on your wrist, you will produce more force than when you put the weight on your fingertips, even though joint torque can be equal and muscular contribution is equal.

If you want to know muscular force production, you need to start with joint torque.

Also, you're mixing up units and quantities. "Seconds" is a unit. "Mass" and "distance" are quantities.

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Joshua Slocum

Actually you can't really consider them seperately because some muscles cross mutliple joints. Good examples are the biceps and triceps, which cross both the elbow and the shoulder.

There are some theorems in mathematics that may make this a whole lot easier, though. So if we were to do a complete analysis of all factors involved, we could get a reasonable approximation that requires less calculation given certain circumstances (small ranges for muscle/tendon length and such).

I'm talking about calculating the torque about a joint, not finding the required force-production for individual muscles. The torque about the joint is mostly independent of the attachment points of the muscles. What matters [in this specific case] is where the torso's center of mass is, and where the shoulder is. There might be some minor differences due, as you noted, to some muscles spanning the shoulder joint, but it's going to be such a small amount that it's hardly worth considering.

Torque is what matters during movement. The muscles produce force, but there is a lever system involved, so if you want to talk about 'force production' at a joint, you are talking about something imaginary, as the amount of force produced by the joint varies with the lever length of the load. If you put weight on your wrist, you will produce more force than when you put the weight on your fingertips, even though joint torque can be equal and muscular contribution is equal.

If you want to know muscular force production, you need to start with joint torque.

I'm in complete agreement here.

Also, you're mixing up units and quantities. "Seconds" is a unit. "Mass" and "distance" are quantities.

Good catch, thanks.

If you happen to have access to a set of parallel bars, try this experiment: set one bar to be a setting higher. Then do an assisted CTI by placing your upper arms on the lower bar, and gripping the higher bar in an undergrip (you may need to move the bars closer together than normal). You'll find your body ends up being more or less vertical, without an effort on your part. (It will likely deviate to some degree, depending on your body and your shoulder position), but correcting that will be a cinch compared to the strength required for a full lever.

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AlexX

From what I've heard about Jasper (those who are still alive) he was a pretty stand up guy and was pretty humble. He never liked talking about what he could do you just either saw him doing it one day or you had no idea what he was capable of. Yeah it's all talk from people that knew him but I would still be more inclined to believe that if he said he held it.

I also know that John Gill did some analysis and tests with the CTI (I believe you can find them on his site), and he also believes that the CTI how it is shown in the first picture was held for the time that Jasper mentioned.

Of course I am willing to admit that I am a bit biased as I got into bodyweight training after being inspired by Jasper, Edit: Jim (beastskills) and John Gill.

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Rik de Kort

The guy from BeastSkills is called 'Jim', Alex. :P

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AlexX

The guy from BeastSkills is called 'Jim', Alex. :P

Hehe oops. On the other hand when I read your post I was like wait a second how does he know my real name, I think I spent a good 5 minutes trying to figure that out :facepalm:

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Nyikhaj

If we assume, that the arms perpendicular to the body (or at least the angle between them is constant) there are two extremes:

1) bodyline is nearly parallel to the gravity vector

2) CoM is under the bar (support)

In case 1) the maximum of the external torque is on the wrist, the shoulder joint is not loaded with torque (theoretically)

In case 2) the maximum of the external torque is on the shoulder joint, the wrist is not loaded with torque (theoretically); in addition this torque on the shoulder is significantly smaller than that in case 1) on the wrist.

I think no one have a grip strength for case 1) (maybe for nanoseconds). But as one's position is moving toward case 2), CTI is getting possible.

So in my opinion the first picture of the cti (with no legs) is a fake or the guy is in motion.

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alec_ar

And the second photo was probably a three second hold like he claimed it was right?

And btw, am I just crazy Nyikhaj or would there still be a significant amount of external torque on his shoulder in the second photo?

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Joshua Naterman

jfslocum: You do have to consider the muscle attachments. They determine how the pressure gets distributed in the joints. If we want to ignore that, then super simple stuff is just angle of CoM to center of shoulder joint to gravitational vector, with trigonometry applied to the relationship. That tells you the force the bar feels, but not the force you produce in your body.

internal torque is the force the muscles have to produce. External torque is the torque you'd see on a dynamometer (think a force scale).

You are right that the torque is really a measure of force * moment arm, but when you take different moment arms you find that different forces are present along the perpendicular line between force application point and the axis of rotation for a given torque, and that is what I was trying to get at. It takes multiple times the force to produce the same torque at muscle attachment site compared to where the hand holds the bar.

That's the difference between external and internal torque... the applied force. External torque could be the same for everyone of a given body type but if they all have different muscle attachments they will all need different internal torque capabilities to produce the same external torque. This makes it very hard to predict what someone should be able to do simply based on external factors. That was what I meant to say.

Yeah, or you could just note that hips tend to be a reasonable back-of-the-napkin estimate for your center of mass when in a laid out position and use that to get a first-order approximation. Also note that since we're dealing with torque about the shoulders, the arms and the body have to be considered separately.

I have to disagree here, simply because that's not true. The umbilicus AKA belly button (or more accurately maybe 2" below the umbilicus) is your best approximation, particularly with your shoulders flexed nearly 90 degrees. That's a good bit above the hips, unless you meant the upper part of the pelvis. I think I have kind of lost touch with what the general assumption of "hips" means in the non-academic world because your hips are maybe 2-4" above where your greater trochanger is at, and if we measure hip girth it's generally around the trochanters.

This is kind of where I got confused for a while in my studies, because inside a single muscle you get your greatest force production with a maximal isometric contraction. However, when measuring external torque (force the outside world actually experiences) the highest forces are from extremely rapid movements even though this is where muscles are intrinsically the weakest. It's a mixed up crazy world, sports performance is.

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Joshua Slocum

jfslocum: You do have to consider the muscle attachments. They determine how the pressure gets distributed in the joints. If we want to ignore that, then super simple stuff is just angle of CoM to center of shoulder joint to gravitational vector, with trigonometry applied to the relationship. That tells you the force the bar feels, but not the force you produce in your body.

This is true, but even at the most extreme possible configuration, the external torque on the shoulder is still going to be many times less than in a front lever, simply because your center of mass (minus arms) isn't going to be far from your shoulders on the anterior/posterior axis. In fact, you might be able to bring the external torque to zero by pro/re-tracting your shoulders to bring the joint directly over your center of mass.

internal torque is the force the muscles have to produce. External torque is the torque you'd see on a dynamometer (think a force scale).

You are right that the torque is really a measure of force * moment arm, but when you take different moment arms you find that different forces are present along the perpendicular line between force application point and the axis of rotation for a given torque, and that is what I was trying to get at. It takes multiple times the force to produce the same torque at muscle attachment site compared to where the hand holds the bar.

Ok, so "internal torque" is actually a measurement of force? And each muscle has it's own internal torque? So then the sum of (internal torque*muscle lever arm) over all muscles is equal to the external torque?

I have to disagree here, simply because that's not true. The umbilicus AKA belly button (or more accurately maybe 2" below the umbilicus) is your best approximation, particularly with your shoulders flexed nearly 90 degrees. That's a good bit above the hips, unless you meant the upper part of the pelvis. I think I have kind of lost touch with what the general assumption of "hips" means in the non-academic world because your hips are maybe 2-4" above where your greater trochanger is at, and if we measure hip girth it's generally around the trochanters.

Thanks for the correction. Is that for the average human or someone with a gymnast's (top-heavy) body type?

When I said 'hips' I was thinking of the part of the pelvis that protrudes on either side of the body, where a belt might rest if you were wearing pants (I believe 'illiac crest' is the technical term, based on some illustrations I just looked up). I guess 'just below the waist' might be a better term for colloquial use. Sorry about my imprecise terminology: I haven't studied much anatomy.

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Nyikhaj

And the second photo was probably a three second hold like he claimed it was right?

And btw, am I just crazy Nyikhaj or would there still be a significant amount of external torque on his shoulder in the second photo?

I think that is possible. If one's center of mass is under the bar, it is not more tough than a full front lever. (Unfortunately I cannot verify this last statement in practice. :) )

On "torque" I meant the momentum which wants to "open" the body-arm angle. Of course you have to exert force in your shoulders to fix your body to your arms. However you won't struggle maintaining the body-arm angle in (the absolutely theoretical extreme) case 1) (see my post before): gravity will do it.

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Antonio Boyer

I saw this video on facebook and i was wondering what other on the forum thought about it too. the two things i notice is that his arms aren't fully straight and that he is using a false grip.. i'm not sure if that makes it any easier but its different then the way jasper grips it.

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Joshua Slocum

That's very impressive. However, he's using a false grip, his arms are quite bent and his shoulders are well below the height of the bar. A CTI it is not.

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ngoachoi
That's very impressive. However, he's using a false grip, his arms are quite bent and his shoulders are well below the height of the bar. A CTI it is not.

Yup arms r bent I agree definately makes it easier. But even gymnast use false grip for their moves in olympic rings which count as a hold. And about the head height can u show me a pic of jasper with better height and leg position?

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FREDERIC DUPONT

Very nice & very close to a "CTI" to me... :)

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C-Blu
It always seems impossible until you actually see it :)

Hehe, saw you posted a like on that video on the youtube, wanted to share it here, but you were faster.

 

This quite impressing, even performed like this. WIth false grip, at least you can benifit more from CTI, because with normal grip, it is pointless to try to achieve the CTI, because the grip strength is much more demanding as the angle increases. Grip is the weakest link, because of the force of gravity.

 

But in the end, I would choose Victorian Cross as the ultimate strength goal not CTI. It's real, it's very rare, and if you train for it, you will get the ultimate upper body strength.

 

Grip strength problem, I assume, won't let you advance more than this guy. So the upper body strength increase will stop at some point.

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alec_ar

I too saw that on Facebook. If it were real I would be extremely impressed. All the people here who are saying 'arms bent false grip, no CTI' I agree that it would be all the more impressive if it were an ideal hold. That being said, the degree of CTI that this guy supposedly has is very impressive imo.

But coming from someone who has also trained for the CTI, I don't believe that vid is real. I smell fish.

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ngoachoi
Hehe, saw you posted a like on that video on the youtube, wanted to share it here, but you were faster.

 

This quite impressing, even performed like this. WIth false grip, at least you can benifit more from CTI, because with normal grip, it is pointless to try to achieve the CTI, because the grip strength is much more demanding as the angle increases. Grip is the weakest link, because of the force of gravity.

 

But in the end, I would choose Victorian Cross as the ultimate strength goal not CTI. It's real, it's very rare, and if you train for it, you will get the ultimate upper body strength.

 

Grip strength problem, I assume, won't let you advance more than this guy. So the upper body strength increase will stop at some point.

I mqy be wrong, but with this current world wide hype with street workout. I believe its a matter of time before we see a full cti. Give it a couple years or so but it has to come lol..ps I totally agree with the victorian comment

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Alessandro Mainente

the strength you need to perform that skill is very very very high but for sure the false grip can eliminate the grip torque problem. also his shoulders are not at bar level and arms are bent...but...is impressive

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C-Blu
I mqy be wrong, but with this current world wide hype with street workout. I believe its a matter of time before we see a full cti. Give it a couple years or so but it has to come lol..ps I totally agree with the victorian comment

Well, that guy will be a legend if it happens, and all the people who made physical calculations, will have to admit that they understimated human body capabilities.

 

But as for now, even after seeing alot of impessive planches, and front levers and human flags in the workout community, to tell the truth, their strength is not to be compared with Olympic Gymnasts and Circus performers.

 

For example. The planche (with ideal technique) is only a level B skill (in gymnastics FIG rating). Only the best guys in workout community have a solid planche, that is counted in gymnastics. Many can do it with the back bended, but it's inferior level of strength.

And of those who have it perfect even less can do a planche press to handstand (C skill).

I saw a guy from workout community who did maltese on the floor (C skill), but yet the gymnasts have Maltese press to Japanese(Wide) handstand, that is D skill. And not to mention the same skills on the rings, which is much more harder.

 

I guess, for someone to get closer to CTI than the guy on the video, they need to do a lot of hardcore ring training for years. To get the level of olympic gymnasts you have to train for 12-15 years. I don't believe that even the most dedicated and gifted guys in workout community, can do anything against pure training time. Time is time. You can't make progress of 15 years dedicated gymnastic training in 5 years of workout.

So I guess we would likely see the CTI from some gymnasts, circus artists or climbers (yeah, their one arm pullups and grip strength is amazing), if it will ever happen (don't believe in it after reading more physics exlanation behind the movement).

 

Workout movement is inspiring. But in the end, they are several steps behind the gymnastics and circus. It just can't be the other way. It inspires guys(well and girls) to achieve something. Even if they don't have gymnastics background. It shows that a lot of things are real for average people. Workout feats of strength mimic gymnastics elements (I say mimic, because not always they are executed correctly).

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