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Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Fri Oct 05, 2018 3:56 am
by Yeung
The Chinese Administration promoted Taijiquan as a soft exercise, and to them it is just Shaolin Martial Arts does it softly. Maybe this is why people no longer differentiate between use and not use brute force. One of the method is relax and contract as a way of Fajin, but what happen after the so called Fajin? It falls into the trap of stiffen up and takes longer time to relax again. I am doing some experiment on the concept of store and issue non-concentric forces for acceptance to the next European College of Sport Science congress. It is difficult to measure the difference between relax from concentric contraction and recoil from eccentric contraction, but the result is obvious.

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Fri Oct 05, 2018 7:55 am
by cloudz
Can I see;
Brush knee twist step
parry punch
cloud hands
tai chi kicks
pull down
single whip
snake creeps down
cockeral stands on one leg.

all performed with issuing power (fajin): without concentric contraction and only eccentric contraction taking place in the movements/ postures.
If it's real, then the least you can do is show me how you do it. And a description of what differes to the 'regular way' of performance would be a help.

Can you also explain why you think when a tai chi practitioner was scientifically measured why concentric contraction was detected (which I think is fair to assume would be typical) - and then please explain why exactly it would not be detected in your performance. Let's say for argument sake it's a typical Yang style kind of form. Can we do that ?

You must have some answers for that kind of enquiry, otherwise, for me at least, this goes nowhere productive. It would be nice to see it - but a reasonable explanation would make a nice start.

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Mon Oct 08, 2018 2:58 am
by Yeung
cloudz wrote:Can I see;
Brush knee twist step
parry punch
cloud hands
tai chi kicks
pull down
single whip
snake creeps down
cockeral stands on one leg.

all performed with issuing power (fajin): without concentric contraction and only eccentric contraction taking place in the movements/ postures.
If it's real, then the least you can do is show me how you do it. And a description of what differes to the 'regular way' of performance would be a help.

Can you also explain why you think when a tai chi practitioner was scientifically measured why concentric contraction was detected (which I think is fair to assume would be typical) - and then please explain why exactly it would not be detected in your performance. Let's say for argument sake it's a typical Yang style kind of form. Can we do that ?

You must have some answers for that kind of enquiry, otherwise, for me at least, this goes nowhere productive. It would be nice to see it - but a reasonable explanation would make a nice start.


Interesting that you did not mention "grasp the peacock's tail", I think most people work out the application of this signature form of Taijiquan should workout some of your questions.

I have sort of worked on some of your questions in my experiment with fajin workshop:

Experiment with Fa Jin, East Midlands, August 2018
Post by Yeung on Mon Jul 23, 2018 2:30 pm

Experiment with Fa Jin, East Midlands, August 2018

From the classical literature of Taijiquan, Fa Jin has the following characteristics:

1, Store and then issue
2. Store power is like opening a bow
3. Issue power is like shooting an arrow
4. The requirement is the coordination of above and below

Fa Jin is a combination of stored power and generated power to issue an explosive type of power with the coordination of movements of the upper body and the lower limbs. Traditionally the body is described as the movements of 15 joints of arms, legs, and the spine in generating a straight line of attack.

The experiment with Fa Jin sessions will work through various techniques from martial arts that does not use brute force every Saturday from 10 am to 1 pm in August 2018 at the upper hall of Trinity Methodist Church Centre, Royland Road, Loughborough, Leicestershire, LE11 2EH.

Participants will be shown the following:

1. Eccentric strength
2. Stored elastic energy
3, Utilization of stored elastic energy with eccentric strength
4. Utilization of incoming force with stored elastic energy and eccentric strength
5. Practice Fa Jin in various techniques that known to them

The aim of these sessions is to experiment with various possibilities of Fa Jin in martial arts to verify the non-concentric exercise model, and to identify observable differences between pure eccentric strength and combining with stored elastic energy.

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Mon Oct 08, 2018 3:12 am
by cloudz
I thought this was a simple look at the 3 types of muscle contraction and the gross related movements.
https://www.healthline.com/health/conce ... ontraction

I don't object to taking an emphasis to eccentric movements and or contractions. I am just trying to understand why you think concentric contractions are problematic ?
Going by that guide some gross movements like coming up from a squat are concentric or an arm pulling in towards the body, for example; I don't really see how someone practicing TCC can avoid it completely. I would rather accept and work with the reality of this natural phenomena.. I believe in balanced training generally speaking, and I have yet to hear a good reason why certain natural movements need be avoided whether loaded or not.

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Mon Oct 08, 2018 5:03 pm
by marvin8
cloudz wrote:Can you also explain why you think when a tai chi practitioner was scientifically measured why concentric contraction was detected (which I think is fair to assume would be typical) - and then please explain why exactly it would not be detected in your performance. Let's say for argument sake it's a typical Yang style kind of form. Can we do that ?

You (Yeung) answered cloudz by mentioning a past fajin workshop without any explanation of what happened in that workshop that supports non-concentric, martial art movements. A biomechanic or physics explanation, test through surface electrodes or other means should be used as evidence that there are no concentric contractions.

Yeung wrote:Interesting that you did not mention "grasp the peacock's tail", I think most people work out the application of this signature form of Taijiquan should workout some of your questions.

The "Grasp the peacock's tail" and "Absorb Repel" movements appear to use the same eccentric and concentric contractions as an external, orthodox fighter's movement: Pull Back, then counter with a short right hand—which can include shifting weight by folding the inguinal crease.

Mark Rasmus explains (arguably) elastic force using sink and stretch with no weight shift that might be closer to non-concentric movement.

Sifu Mark Rasmus
Published on Aug 7, 2015:

https://www.youtube.com/watch?v=ec8LmxGAlXY

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Tue Oct 09, 2018 2:10 pm
by Yeung
Actually, I am trying to address the question of what you will do next if someone neutralized and retaliated your most powerful strike? This will have to verify the techniques involve in striking, neutralization, and retaliation in additional to the possible responses. The subjects need to know how to do it, undergo various tests to confirm their correctness, and interview them to confirm their experiences. It is not possible to do comparative studies until some sort of standards are achieved.

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Wed Oct 24, 2018 7:23 am
by Ron Panunto
Question - is holding postures, like sitting the horse and zhang zhuan considered eccentric or isometric?

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Thu Oct 25, 2018 2:33 am
by Yeung
Ron Panunto wrote:Question - is holding postures, like sitting the horse and zhang zhuan considered eccentric or isometric?


Good question because isometric can be eccentric, concentric, or both in a static posture. Maybe what you are looking for is how to do a passive stance, or just standing passively.

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Thu Oct 25, 2018 7:58 am
by Ron Panunto
Well, my thought is that standing postures are the essence of developing internal strength, and eccentric muscle contraction can be considered as a "braking" type movement, that is when we are sitting the horse, our thighs are parallel to the ground and our quadriceps are contracted eccentrically as a "brake" to keep us from falling to the ground. The same in zhang zhuan where we are standing as if sitting on a bar stool, and when tree hugging is added, the anterior deltoids are eccentrically contracted as a brake to keep our arms from falling down. My point is that if my analysis is true, then eccentric muscular contraction does indeed play an important part in the internal arts.

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Thu Oct 25, 2018 8:27 am
by Steve James
In order to stand, one must resist the force of gravity. It seems to push down, so one has to push back. The more the knees are bent, the more the leg muscles must resist. If this weren't so, standing wouldn't be exercise.

I thought that isometric meant exerting force without movement. I'd argue that there is movement even while standing. Imo, an isometric exercise would be to lay down and use the legs to push up on something stationary.

Re: Biomechanics of Non-concentric Martial Arts

PostPosted: Fri Oct 26, 2018 2:28 am
by Yeung
Ron Panunto wrote:Well, my thought is that standing postures are the essence of developing internal strength, and eccentric muscle contraction can be considered as a "braking" type movement, that is when we are sitting the horse, our thighs are parallel to the ground and our quadriceps are contracted eccentrically as a "brake" to keep us from falling to the ground. The same in zhang zhuan where we are standing as if sitting on a bar stool, and when tree hugging is added, the anterior deltoids are eccentrically contracted as a brake to keep our arms from falling down. My point is that if my analysis is true, then eccentric muscular contraction does indeed play an important part in the internal arts.

Thanks, I think you sort of explained passive stretching as "braking" type of movement. In fact muscles are being pull by the weight of the arm or the torso in the case of quadriceps. It is using gravity to activate muscles without work or contract muscle concentrically. In some cases of zhang Zhuang, people tend to contract muscle concentrically to maintain stability in their stances. But this can be avoided by activating the gluteal muscles.