A clarification on "reflexive stability"

Matt

Level 3 Valued Member
I know everyone can read it for themselves, but the article Brett initially posted talks about this too.  I was going to mention it yesterday but couldn't read some of the references.  Yet :
In some circumstances, a combination of both feedforward and feedback control exists, such as during the maintenance of postural control.6 Additionally, consider the situation in which a subject watches a tester trigger a device that induces a joint perturbation. Many subjects will naturally ‘‘tense up’’ when they see the tester beginning to push the trigger before the perturbation. Whether the muscle activation before the perturbation reaching the joint is the result of feedforward or feedback control remains controversial. For this reason, the term feedforward control has been recommended to describe actions occurring upon the identification of the beginning, as well as the effects, of an impending event or stimulus.4,5,7"
Brandon and Brett have put that in their own words too.
I was thinking of a similar thing in an earlier post when my response to my anticipation of an event was much more than the direct stimulus (my eye reading a number on the screen).
To be fair, I can also see how Scientist can claim they are learnt motor patterns, not reflexive (where a reflexive response must always at all times be a response from a nerve being stimulated, not anticipating the stimulation)?  A baby or an ignorant newbie learns these responses from direct stimulation then anticipates.  YET a baby has a direct stimulus (gravity) from day 1 and so straight away is learning to "control" it's huge range of mobility (ie. stabilise reflexively).  This is probably talked about somewhere in the paper Brett referenced or it's followup.
Something that surprised me - these concepts and terms are over 100years old, involving a Noble Laureate.  The paper Brett referenced outline some changes in terminology today, yet you'd think the discussion we're having has been had over and over already?
 

Matt

Level 3 Valued Member
Umm, sorry about the double-post.  No I am not seeing double this New Years day.  The second has a spelling typo corrected, somehow I did this with some tweakage of IE's feedforward-feedback...
 

Brett Jones

StrongFirst Director of Education
Master Certified Instructor
Beast Tamer
Sean,

Again - you know my feelings on this and on your level of experience and knowledge on this and other areas so stopping now would be a good idea IMO

Happy New Year

 
 

Matt

Level 3 Valued Member
Ha - the second post of this discussion by Brett :

The inputs are visual, vestibular, proprioceptive... 7 pages later...

 
 

Matt

Level 3 Valued Member
Sean, perhaps what you are wondering about is considered in the literature as muscular coactivation, which is related to this discussion on reflexive stability.  A global behaviour, not a linear cause and effect.  Maybe.
 

Sean Schniederjan

Level 3 Valued Member
"Brett,

“…after an imposed joint perturbation…”

RS is being defined as anticipatory. If we are talking about a response to a perturbation, it can’t be anticipatory.  It is a response. Why is this so hard to understand?"

Good point here, anticipatory is not a good word choice here if you want it to include things that are not anticipatory.
 

Matt

Level 3 Valued Member
Onto the second half of Scientist's question.

Can reflexive stability be trained - or reflexive strength improved, strengthened? (or to quote him : " The reason this matters is that motor learning can be trained, but reflexes cannot. So it seems suspicious when I hear people talking about training “reflexive stability” when I know (at least I think I know, but could be wrong) that reflexes cannot be developed and trained – they are innate. Muscles can become stronger, and motor patterns can be learned, but nobody is adding a new stretch reflex that they didn’t have before through training."

I would consider a baby first learning to pick up something.  It is clueless how much force to apply etc - it's brain is clueless how to position the joints to be able to generate such a force etc. etc.  So it probably either uses too much or too little force.  Yet after a while it learns to control this.

Same way - I could try for a  heavy DL and not budge the bar.  But after some training, get stronger and lift it.  In the same way a baby learns control it's reflexive "strength", I am getting stronger reflexively to be able to generate right stability-force combo etc. in the right sequence to be able to make the DL.

So yes - I believe it could be trained.
 

Matt

Level 3 Valued Member
Brett - ? what reflexive stability is involved in diaphragmatic breathing if any?  I guess it would be pretty low intensity if there is.
 

Brett Jones

StrongFirst Director of Education
Master Certified Instructor
Beast Tamer
Matt,

Flip the question - how is diaphragmatic breathing involved in motor control/reflexive stability?

 

For clarity - the anticipatory comment being batted around is from OS not from anything I have posted
 

Matt

Level 3 Valued Member
Hmm, thanks for the homework Brett :) New Year and I’m already hitting the books. I’ll ponder that now as I go for a walk.

Happy New Year, thanks!

(Aim for the new year - to post here and not have to edit after every post?! I am forum typing dyslexic or whatever word describes it..)
 

The Scientist

Level 3 Valued Member
Brandon,

You said: "As far as Brett’s quoted ” after an imposed perterbation”.  If they eyes are opened and the individual can see what is going to cause the perterpation, there will be an anticipatory response prior to the perterpation (almost like a learned behavior, hmm)."

It seems like you are making my point for me. If you see something coming and anticipate a perturbation before it actually happens, this simply cannot be reflex. This is the engagement of a complex motor response that involves enormous amounts of  integration that goes far beyond reflex circuits.

Now, if you don't see the perturbation coming and begin to fall, this is when reflexes may become active. In my first post I said:

"To me, it sounds like the “anticipate movement before it actually moves” part suggests that what they are actually attempting to describe is motor learning and patterning. This is a critically important thing for movement, but it really is not a reflex at all."

... and it is coming back around to the same again now. This big problem I have with all of this that everyone is dodging or ignoring is saying that reflexes can anticipate. They can't. It is just not possible. There must be a stimulus, and if you are anticipating the stimulus, it can't possibly have occurred yet. I think I have now exhausted my desire to pursue this, so I'll let it go now.
 

Brett Jones

StrongFirst Director of Education
Master Certified Instructor
Beast Tamer
Scientist

Again “you are arguing one point off of a definition I did not provide....
but as Brandon noted “anticipatory” does not negate the concept of reflexive response or reflexive stability but rather can be part of the discussion”

Visual input is a stimulus – so it can be part of a reflex “action”
(the highest order input actually)

If you use the definitions I provided off of the article referenced I think we are actually pretty close to agreement IMO
Or should be contact the authors and inform them that they are wrong?
 

The Scientist

Level 3 Valued Member
Brett,

This definition?

"Specifically, from a joint stability perspective, we define neuromuscular control as the unconscious activation of dynamic restraints occurring in preparation for and in response to joint motion and loading for the purpose of maintaining and restoring functional joint stability. Although neuromuscular control underlies all motor activities in some form, it is not easily separated from the neural commands controlling the overall motor program. For example, in throwing a ball, particular muscle activation sequences occur in the rotator cuff muscles to ensure that the optimal glenohumeral alignment and compression required for joint stability are provided. These muscle activations take place unconsciously and synonymously with the voluntary muscle activations directly associated with the particulars of the task…”

They are defining neuromuscular control. Reflexes are not mentioned. I think you may be making the mistake of using the terms unconscious and reflex interchangeably. Most unconscious actions are not reflexes, even though reflex are unconscious. If you are proposing to replace the term "reflexes stability" with "neuromuscular control", I think that would be perfect and would solve the entire problem.
 

Brett Jones

StrongFirst Director of Education
Master Certified Instructor
Beast Tamer
I certainly prefer the term "motor control" to stability or reflexive stability so neuromuscular control does encompass the issue much better

 
 

Matt

Level 3 Valued Member
I hate to disagree Scientist, especially since you two are the experts.

To me reflexive stability is the appropriate, logically consistent terminology.

As I understand it, from the context in that it is used, the meaning of reflexive is: a response to a stimulus.

That stimulus could be anticipation (imagined fear for example) = input. The response ie. reflex = stability and perhaps movement or some action.

Visual stimulus = input. Response ie. reflex = stability etc in anticipation of a future movement.

The stimulus can be quite varied – direct/tactile, imagined, initiated ie. wilful, and of course the three Brett mentioned visual, balance and proprioception. These are often anticipating a future and create stability for that movement – but there is a consistent causal logic here of input-response-output. The response is reactionary to the input, therefore a reflex in the same manner that a literal physical reflex responds to stimulation. How this is done is a combination fo feedforward and feedback loops with different timing within neural circuitry related to this.

The reflexive response is to the brain anticipating, but there’s no ”reflex” anticipating. Even if you use the anticipation of a knee-tap as a consideration, the reflex does reacting to the tap but the timing and what the body does is different if you can and can’t see the tap. The reaction time for example (an obvious one) is different etc. So here there is perhaps double reflexive stability. But this example where a reflex in the literal sense is involved is a subset of a larger sense of the use of reflexive in my understanding, and so shouldn’t be THE only conceptual situation considered.

To me it seems you want to insist Scientist of the meaning of reflexive stability as stability-reflex – and to me that’s not what it is trying to describe as Brett, Brandon and others have been saying.

If you would use the term motor control it would be too general, as motor control would encompass muscle relaxation, the opposite of stability.
 
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