Homoeostasis Performance Model

Homoeostasis Performance Model is a synthesis between Noakes’s Central Governor Model and Schmidt’s Conceptual Model of Human Performance. Some of the Bernstein’s conclusions about motor controler, who controls human movement, were:

  • Control system is hierarchycally organized on couple of levels
  • There is a feed-back that connects lower parts with higher parts of control system, which is used to adjust motor comands
  • Time lag between neural connections finaly leads to a need of combining signals from feed-back with feed-forward preprogrammed, anticipatory signals
  • Number of degrees of freedom of the motor system is always bigger than needed. System is redundant and the control can be viewed as the process of solving redundancy problems (finding the optimal control strategy - learning)

So basically, skill is a result of the process of searching the optimal solution for a particular motor task/problem. Abilities are the undelying (hiden, latent) factors that affect performance and skill. But abilities are also measured via performance, so there is no such thing as a crisp boundary between skills and abilities. When you want to measure strength, you can give someone to do 1RM squat. But doing squats takes skill to accomplish, especially with begginers. So, I would say that stregth is a skill, rather than a some hidden, latent factor – ability. Same thing for a endurance, speed, flexibility, agility and other.

I am not saying here that there is no such thing as abilities, but I am saying that it is hard (or maybe impossible) to put the line between skills and abilities, because they are interelated, and cannot exist by themself alone.

It is quite helpfull to look at the things that, specific skill uses specific abilities to solve specific problems. If there is no needful development of underlying specific ability, then the skill cannot be learned nor performed. It is imposible to teach someone to squat 200kg with proper skill (technique) if his level of strength (ability) is poor. Same thing with sprinting form. It cannot be learned nor reached if the underlying strengths and flexibilities (and endurance to maintain it) are not well developed. Pushing the athlete to do something he cannot do because of the lack of underlying abilities is only frustrating and can lead to injuryes.

Skill is NOT such thing as stereotype or fixed patter (of muscular activation), but rather a dynamic, complex, continual motor problem solving. To teach some skill, you should not give answers but rather questions.

Ability structure makes things more complex, because there is no consensus about their number nor interrelation. This is also one more proof that the line between skills and abilities is hardly made. There is one general ability which correlates with every other. Is is coordination. Coordination is specific ability to control movement, but there is also a number of types of coordination. This makes things more complex. We can look at the coordination as the connection between skill and abilities.

There is a trend in my country (Serbia) to develop coordination with youth, which can help later with learning and performing sport specific skills. The question is can coordination be developed, by the way, there is different types of coordination. I am thinking that giving kids a various exercises does not improve coordination (or it is) but rather enrich their motor space, so there is a skill transfer later in their sport development to more specific sport skills. This is not the issue here, so we are going to leave this debate for some other time.

So what the hell is new here? What new does Homoeostasis Performance Model bring to the world? This was just an introduction, so lets start…

The main thing that Homoeostasis Performance Model brings is the integral approach to study human movement. It is time to stop reductionist approach dividing motor control for creating movement and physiological metabolic/energy systems that maintain life. The human acts as a whole and thats the way it should be viewed and explored.

The main principle/concept of Homoeostasis Performance Model is that movement is allways done within the limits of homoeostasis (in healthy humans). I will first explain my point of view for „movement“, then for „homoeostasis“ and finaly for their interaction.

Movement is an interplay between stability and mobility. To allow movement to happen, at the specific instant of time, some joints must be stable and stiff, while others must be mobile. Movement is an act of the whole body (not just muscles according to this model), even when you move your little finger, your whole body moves. Take an example. Stay upright with your arms by your side. Quickly rise your arms. Which are the muscles that activated first? Deltoideus? Not exactly, your leg and core muscles, because they must maintain your whole body balance and prevent you not to fall, and also, they have to maintain the stability of the individual joints (spine). This is an example of anticipatory postural adjustments. Because system is redundant, which means that there is unlimited number of solutions, motor controler must find the best/optimal way to produced desired movement and to solve desired motor task. This is a process of searching. This is the motor learning, finding the optimal control strategy to solve some motor problem. The result of this searching (motor learning) is the motor skill.

Muscles produces forces (torque) and, in the same time, stiffness (short range active stiffness) which allows them, with the pair of their antagonists, to stabilize joints and to move joints.

Movement is bigger then the sum of its components, so trying to isolate one movement (and muscle) is misleading and errorneous. As Zatsiorsky stated, we are not trying to imporove our muscles but rather our movements. One my friend, when someone asked him, while doing cleans, for what muscle is that exercise, he answered: „Do you know that muscle that works when you jump to catch a ball under the baskett? It is for that muscle!“.

Homoeostasis is an inner (only inner?) physiological enviroment that should be stable and maintained under narrow boundaries to maintain life. Take the body temperature for an example. Body temperature is about 37C, but when it crosses 44C or fall below 33C, you die! End of story. So to maintain life, your body must control its internal enviroment (its state). There is a lot of variables that should be controled: body temperature, blood sugar, hydration, nutritional status of the blood, biochemistry status of blood, pressure and a lot of others. Dont forget that between them is a strong correlation and interaction, so your control mechanism have a very complex job to do to keep you alive.

To maintain homoeostasis, control mechanism have couple of systems to help him (executables). That includes circulatory system, respiratory system, digestive system, termoregulatory system, urinal system. Control mechanism comunicate between them via hormonal system and neural system. It is hard to find localization of the homoeostasis control system, because same as motor controler (are they the same?) have hierarchical structure and it is widespread over the body. Sometimes it is said that hypotalamus is the main controler, but I think it is maybe just one (highest) part, because a lot of organs have their control systems in themselves.

To maintain life, control mechanism have to find the optimal relation between different variables which defines homoeostasis, but again, it have to find optimal way controling-keeping them in the narrow ranges. I dont know is the human body one state system (representative point), but something tells me maybe it can have couple of stable states and switch form one to another as a result of training or some sickness.

If we take some paralels with cybernetics and automatics, homoeostasis control mechanism need to have defined goal of control (relation between variables – representative point) which there is maybe more of them, algorithm or optimal control to maintain it within narrow ranges (the process of searching) and gain which helps him to do it quickly and effectively. We can look at the gain as a functioning of physiological systems (heart, lungs, blood etc). Making them more efficient, creates greater gain in the systems and thus allows homoeostasis control mechanism better control and maintaining of homoeostasis.

Are these two systems really separated or not? Homoeostasis Performance Model states that they are not! According to this model, movement is allways done within the limits of homoeostasis and the homoeostasis is never lost (in healthy humans). If there is a threat to homoeostasis, movement is stoped or altered. Take an example of exercise in altitude. Do you expect to find more or less lactate in the blood? You expect to find more, but contrary you found less, because motor/homoeostasis controler shuts down-decrease the muslce activation to maintain homoeostasis. The feed-back to the motor/homoeostasis controler from the muscles and other organs via III and IV afferent fibers, informs it about what is happening „down-there“ – is there a threat to exit from homoeostasis? This is a new concept added to classicaly Bernstein motor controler. Controler gets feed-back information form chemoreceptors at the periphery and acts by increasing the functioning of heart, lunges and other physiological systems or by decreasing/altering muscle activation for the goal of maintaining homoeostasis. Controles only permits movement within the ranges of homoeostasis.

Homoeostasis Performance Model brings another point of view at the fatigue. Fatigue is not a physiological impairment, but rather protective mechanism that acts as body trys to leave boundaryes of homoeostasis (which starst at the onset of exercise). Sense of effort (RPE, rate of percieved exertion) is a concious perception of subconcious (underlying) integrative effort of control mechanisms to maintaing homoeostasis.

To improve you performance you must improve your motor skills and ability to maintain homoestasis. That includes improving you control strategy (learning) for both motor controler and homoeostasis controler which is done by practicing. Motor controler develop skill, and homoeostasis controler develop optimal control of heart, lunges, urinal tract etc. Both of these two result in pacing strategy, as an example, in running. Also, you must develop the gain in the system, as a result of training adaptation. Gain in motor controler represents motor abilities, and in homoeostasis controler represent functioning level of heart, lunges etc. And finaly you must improve you mental ability of „pushing“ or stimulating homoeostasis controler while it de-stimulates you with sense of effort (or RPE).

It is obvious that I differentiate between learning and adaptation. Learning represent searching for the optimal control, and adaptation represent increasing the system gain. They are different but interconnected. Both have to be improved for the performance to improve.

According to Homoeostasis Performance Model, endurance is a ability to maintain homoeostasis. It is maybe most fundamental ability (?) more than strength, because also when you push 1RM bench press, it takes time, and for that time homoeostasis must be maintained. This includes joint stability, tendom integrity etc.
There is alway reserve for life-threating situations. Movement is allways done within the boundaryes of homoeostasis. Dont forget that homoeostasis controler is still learning and that internal/external enviroment is always changing, so sometimes it cannot compensate for the changes, and injuries happen! There is also a posible threats with psycho-stimulans usage, because it affects you „pushing it“ too much.
Note that for the purpose of better explanation I splitted this controler to motor and homoeostasis but really they are the same.

Comments, critiques welcome!

BTW I got some questions formyself!
If this controler limits maximum force to maintain tendon and joint integity and prevent muscle injuries, why then there is a difference between concentric and eccentric force in vivo conditions as in vitro, and why there is bilateral deficit? Why those forces are not the same?

It seems like i am always the first to respond to these type of posts. :slight_smile:

It seems like a good model in qualitative terms. Could you post a larger feedback diagram? (Breaking up some of the larger blocks in the model). It would be easier to discuss this model this way as my knowledge of physiology (minus some perception stuff involving hearing) is not the greatest.

I do admit that i personally enjoy these models that involve control theory and information theory . (BTW, it would be interesting to apply both of these fields to this model).

Quark, tnx for your interests and reply! I will expand more on this topic-expanding diagrams as soon as I go get a book from my friend (Motor Learning and performance). On the other hand it is quite hard to do a splitting of a controler because there is a concious part and not-concious part and their interaction is unknown. On the other hand, interactions between components of this model are done also on the periphery level (III and IV afferents affecting alfa-MN and its sinapse in the spine etc.). I will give my best to this job… even if you are the only interested Quark :slight_smile:

To allow best performance, as said, you must improve your skils and ability to maintain homooestasis (and mental abilities). Homoeostasis could be more expanded into conserving joint integrity, tendon integrity, avoid muscle strains and sprains etc.
So, to develop maximum performance you must develop skill and underlying abilities with specific high-intensity training, but aslo you must maintain your ability to maintaing homooestasis by doing low-intensity general work to improve capilarization, heart and luns function, tendon and joints. From the point of Homoeostasis Performance Model, Francis HI/LI approach is highly approved and correct!

Sounds good. I will be looking forward to it.

You know what I am thinking? To create a web page, and to explain more on this issue and ints impact on training because it refects my cuurent point of view at the subject… I will translate and include a lot of my other works and papers… this is going to be a job… we will see!
Also, I am thinking to defend this theory (and Central Governor) as my graduate work (final exam) so I am going to expand on the subject!

Quark, about that graphs… hm… The things arent clear that much in my head that I could just put the graph on the paper… I will try that, but it is tough work! So, for now, I will redirect you to find articles from Tim Noakes and his coleagues… There is about 10 articles and they are all free to download. You can find them among www.powerrunning.com articles, or by google, just type Noakes, or something, and ofcourse at the site of Br J Sport Med website!
Also, I strongly recomend reading Motor Learning and performance from Schmidt! It is a must have book!

I will look into those articles. Don’t know when i will have time to look into that book. I have a bunch of references to my own research that i still need to read. :slight_smile: It is cool that you are doing this for grad school. When are you planning on defending?

I am listening 4th year of studies till 1. april 2006, then I plan giving some exams, and, to graduate till september 2006… Tnx for asking :slight_smile:

This waves-oscilations in biorhythm affects performance. As I stated before (http://www.charliefrancis.com/community/showthread.php?t=11026) training should adapt to these waves (providing unloading when needed) and on the other hand athlete should adapt his waves to training (pre-planed unloadings) to allow peaking for the given moment –competition!

Quark, go to wikipedia and type homoeostasis, the article is very good!

I expanded the conceptual model… The comments and futher explanation will come in due course, because it is 2am and I am feeling sleepy…
Till the next time try figuring out on your own :slight_smile:

  • Graph is based on Noakes and Schmidt work as stated before (I am not a copy-pase creator)

Firts of all, it is quite hard to distinguish between conscious and subconscious part. Maybe there is no line at all, but I must say that I am proponent of Descartes dualism, so I strongly believe in „something“ that is not material (soul, spirit or call it whatever you want)! I dont belive that my behaviour and my existance is just biochemical process in brain cells or some complex algorhyth(s) as stated by strong AI proponents. In every motor control book, there is explanation of motor control from periphery to CNS, but I didnt find no one asking who or what triggers first neuron to fire? I dont belive it is somekind of random processes, I strongly believe in free will… But we will leave this issue for some other time!

Conscious part is there to feel (perception) and to act or to set goals! When you move your hand, you dont voluntary activate your muscles, but you just set goals to a motor controler what to do and it creates movement based on his ability to control it optimaly (skill).

Perception from outter world is filtrated trough your current emotions, attitudes etc, you never got it in pure shape (only if you are enlightemented :slight_smile: ) RPE (rate of percieved exertion) is also a perception of how hard is homoeostasis controler working to maintain your state in the boundaries of life. RPE is aso affected from your expectations, emotions, prior experience etc. Based on you mental strength (will power) you can push homoeostasis controler to work harder, while it tryes to „break“ your will with RPE feeling-perception! What is the purpose of RPE (teleology) if the fatigue is just some physiological impairment? So, according to this model, fatigue is a protective control mechnism, which shut-down or alter your performance to keep the homoeostasis between boundaries. This do not exclude the posibility of peripheral fatigue, just it states that homoeostasis in never lost in exercising, and that movement is altered before it is too late. Some drugs (stimulans) can change this and can lead to homoeostasis lost and finaly to death!
When you try to execute some movement, you give a feed-forward information to homoeostasis controler so it can act much faster and not to wait deteoriation of the homoeostasis. To maintain homoeostasis, its controler activates heart, lungs, metabolic pathways, vascular system, detoxification system and finaly it alters movement execution via his connectons with motor controler.

Everytime something changes in the system (human body), in most case gain of the system or in other words function of cardiovascular, respiratory systems, muscle etc. , motor controler and homoeostasis controler must find a better way to control its behaviour. It is a process of finding the best/optimal control strategy based on some criteriums. Criteriums can be various: speed of motion, energy efficasy etc. So every time you improve your abilities you must improve your skill. Take an example. If you improve your arm strength without practicing free shots in the same time, you motor controler will use same control strategy but your muscle are producing more force so you will miss the shots. You must give a time for motor controler (and homoeostasis controler) to adapt, to find the best control strategy, so the best solution is to practice free shots while improving strength! For this same reason, interval training is better than continuous, because it forces homoeostais controler to find stabile state more that once as is the case with continuous running. When doing continuous runs, controler find the stabile state and keeps it while with interval training he must learn to find it more quicker and more than once and to learn to use muscle more efficiently (neuromuscular coordination). This is why a allways say that endurance is a skill!

I am very interested. Haven’t digested it all yet, but I will. You might imagine that I’m interested in motor learning issues :wink:

Cool :cool:
If you have some questions, suggestions, please post! Tnx

Looking at the diagram, wouldn’t it be clearer to pull the right hand comparitor and attach it to the sensory path this could differenciate between sensory information from vision, inner-ear, haptics etc. and the internal sensors (golgi tendon etc.) as there are different pathways for both processes.

I have more to add regarding the AI bussiness, but i won’t be about to comment on that till i am done with my last final… :slight_smile:

Actually, the right part of the graph is mostly from Conceptual Model of Human Performance (Schmidt’s Motor Learning and Performance book). The stimuli from eyes, vestibular, etc are considered as exteroceptors (stimuli outside the body)! Actually stimuli from muscles via III and IV afferents (chemoreceptors) can affect motor program or synapses causing “fatigue”. It is hard to differentiate, but I think the both controlers are actually ONE! But this is easyer to understand…