Introduction
One of the questions I have heard more and more lately in the clinic is, “Where did you learn this technique?” To answer this question is my motivation in writing this article for the newsletter. Bare with me because I know this a long read, but I feel it is very important in the understanding of your musculoskeletal pain that most of you see me for in the clinic
First of all, I did not learn it in a book while doing my schooling as a physical therapist at the College of St. Scholastica in Duluth, Minnesota from 1980-1982. Although I can’t deny it gave me a foundation of physical therapy knowledge and techniques from which helped formulate what I am currently doing in the clinic, it was my experience as a nordic ski jumper for 23 years that was the greatest influence.
Nordic ski jumping is a very unique sport from the standpoint that you are not just defying the force of gravity as seen in most sports, but you begin the skill with your feet in contact with the ground, vault your body into the air, fly through the air, and hopefully land with your feet again in contact with the ground. Just think about what has to happen with an athlete’s nervous, muscular, fascial, and skeletal systems to do such a skill. If I had to pick one phrase to describe it, it would be “skeletal balance and equilibrium.”
Being the analytical person that I am, I just did not try to perform this athletic skill successfully, but would try to analyze in my mind what I was actually doing. In fact over and over again I would hear from my coaches, “Kern, you think too much!” But what really got my inquisitive juices flowing was when my ski jumping technique changed after a traumatic knee injury and resultant surgery while training to make the 1972 U.S. Olympic Team. I don’t have to tell you about my dream of making the team that Olympic cycle.
After my surgery and rehabilitation for a what was a medial meniscus and medial ligament tear of my left knee, I started jumping again during the late fall and winter of 1972-1973. On my first jump, I knew something was different. With each successive jump, I was consistently jumping off to the right from the take off and consistently drifting back over to the left while flying through the air in order to land in the center of what is referred to as the “landing.” I know I wasn’t doing this before my injury, surgery, and rehab.
What was even more amazing to me, this all happened without my conscious awareness. How could it be when reaching speeds of 60-70 mph at take off. Instead, it was occurring at a subconscious level. Of course, that created even more unanswered questions that started me on this path to understand the dynamic process of “skeletal balance and equilibrium.” I guess Albert Einstein was correct in stating, “The important thing is to never stop questioning.” I have always felt there is more insight in the questions you ask than the answers given. I must have drove my parents crazy.
In competing for the United States Ski Team from 1973-1981 and then for the United States Olympic Team in 1976, I was very fortunate to see some of the best athletes in the world at that time performing the skill of nordic ski jumping. From that experience, there is one thing I am absolutely sure of and that is no one did this skill in an identical manner. Everyone had their own style. That is when I came to a realization then as I now do in the clinic, that everyone has their own way, their own technique of finding “skeletal balance and equilibrium” that is influenced by their innate ability and their experiences.
Some of the questions I had while competing about skeletal balance and equilibrium are the same questions I now have about the status and performance of my clients when they are performing their activities of daily living. That is because whether performing an athletic skill or functional activities successfully, the foundation has to be skeletal balance and equilibrium. But unfortunately, there is no place to find detailed information and an integrated view of this important dynamic process. No one as of yet has put it all together to understand what is happening with the human nervous, muscular, and fascial systems to create skeletal balance and equilibrium.
Initially after getting my degree in physical therapy, I treated my client’s musculoskeletal pain with an emphasis on a physical defect as its etiology. After all, that is what I was taught from the Western medical point of view. Therefore, my treatment focused on such things as bad posture, poor alignment, weak core muscles, muscle imbalances, a bulging disc, or even a genetic defect. Not to say that this was wrong, but it doesn’t give the whole picture of what is going on with someone experiencing musculoskeletal pain.
But after forty years of practice (ha,ha!), I came to an important realization that what I was seeing with my clients in the clinic had more to do with their habits and behaviors than anything else. A “training effect” on their nervous system affecting the position and motion of their skeletal structure. Overtime, they have trained their nervous system to react to the consistent forces of ground and gravity in a certain way. Most likely, a “dysfunctional” way.
Thus, the training of their nervous system became my focus in treatment of their musculoskeletal pain and not a possible pathology. Their nervous system that includes both the central (CNS) and peripheral (PNS) systems. As a result, the goal at my clinic has now become altering their habits and behaviors.
By changing the focus on their nervous system, I found that when someone feels better after treatment, it is because they have been successful in altering their habits and behaviors of posture and movement that has been imprinted on their nervous system over time. In chosing this path, it may not be the “quick fix” most people look for when managing their pain and rehabilitating from an injury, but it is a path to long lasting relief of their symptoms allowing them to move better and to generally feel better. On top of that, prevent future episodes of musculoskeletal injury and pain.
In reflecting upon my nordic ski jumping days, the best in the sport were not those who were the strongest, fastest, or most flexible. In fact, I would say most jumpers were pretty equal when using these parameters. Don’t get me wrong, these factors of physical fitness help in the performance of any athletic skill and activities of daily living. However the best in the world of ski jumping were those with the highest quality of movement, the best coordination, and the best timing. Simply, the best organization of their nervous system controlling their skeletal structure in the performance of this athletic skill. The best output of their nervous system in creating skeletal balance and equilibrium.
Skeletal Balance and Equilibrium
By now, I am sure you are asking, “What is skeletal balance and equilibrium?” If you look up the word balance in the dictionary, you will usually find a very simplistic definition stating that it is what prevents humans from falling over while standing, sitting, and moving. But it is just not that simple.
Another word you will hear along with balance is “equilibrium” which is defined as the physical state of the body in which opposing forces are balanced or cancel each other out. When discussing balance and equilibrium, “homeostasis” also has to be mentioned. It means the steady state of internal and external conditions within the body maintained by the nervous system. Simply, a condition of “optimal functioning.”
So when I am talking about skeletal balance and equilibrium, I am talking more specifically about the forces of gravity and ground reaction which is an effect of gravity and how the human nervous system is able to cancel out these forces affecting the position and motion of the skeletal system.
Internal and External Forces
When talking bout skeletal balance and equilibrium, both internal and external forces that affect the human skeletal structure have to be understood. The internal forces on the human skeletal structure are the tension or tensile forces produced by the body’s muscles, tendons, ligaments, and fascia. These internal, tensile forces produced are responsible for cancelling out the two main external forces of gravity and ground reaction. There are other external forces that affect the skeletal structure such as friction and momentum which I will mention later, but it is gravity and ground reaction that are the two primary forces.
That is because these two external forces are constant and never really change. The force of gravity actually has been found to compress the human body to the equivalent of 15 pounds per square inch. That is unless you are at a higher altitude where the effect of gravity on the skeletal structure is less.
But for the most part, all of us are athletes competing against the same constant force of gravity and ground reaction everyday. Ground reaction force is simply equal in magnitude and opposite to the direction of gravity going together like peanut butter and jelly.
I know you have heard of the therapy called “structural integration” or Rolfing created by Ida Rolf. She has a quote that describes the effect of gravity: “Gravity is always there. You can never escape it. From the day the single cell is fertilized and develops, gravity is with us. The fetus in the woman’s womb is under the effect of gravity; and until the undertaker gets the body and lays it away, it’s under the effect of gravity.”
Whether sitting on a chair or standing with the feet on the ground, these two external forces have to be canceled out by the body’s internal, tensile forces to create the state of skeletal balance and equilibrium. Gravity is what pulls a person down into a chair and the chair pushes up against the person’s pelvic girdle as opposite and equal forces.
To truly understand gravity and its effects on the body, let’s get a more complete definition as well as define other terms closely related to this primary external force. Gravity is in fact the very matrix of our world here on earth being a silent dictator that rules us. We as humans living on earth are in constant competition everyday against gravity no matter the activity. Listen to Ranier Maria Rilke (1875-1926) an Austrian poet and novelist and what he said about the importance of gravity in our lives, “How surely gravity’s law, strong as an ocean current, takes hold of the strongest thing and pulls it toward the heart of the world.”
Terms of Gravity
The center of gravity (COG) of the human skeletal structure is not an actual physical point, but a hypothetical point around which the force of gravity appears to act. It is the point around which the skeletal structure can freely rotate in all directions. It also can be defined as the hypothetical point where the sum of all linear and rotatory forces and force movements acting on the human skeletal structure are zero. This is also where the weight of the body is considered to be concentrated and about which all the parts of the body are balanced. But keep in mind that because it is a hypothetical point, its position will change. Just look at the picture below.
It is considered a hypothetical point because the skeletal structure’s COG changes as the body’s individual or isolated parts change in position. Therefore, consider the body’s COG as the sum of its individual or isolated parts. More precisely, it is the constant flow of information coming from the nervous system regarding the body’s isolated joints that is integrated and processed by the nervous system that will alter or change the body’s COG. This is an important concept to remember when looking at the nervous system output and the compensation seen with the skeletal structure.
In standing, the body’s COG ideally is located anterior to the second sacral segment equally distanced between the front and back and right and left sides of the pelvic girdle. This is the “ideal” position standing representing homeostasis or “optimal functioning” of the skeletal structure. But again, the body’s COG will change with each position such as when sitting where the COG is located slightly higher than when standing.
The line of gravity (LOG) is another term associated with gravity. It too is a hypothetical, imaginary, vertical line which fall through the body’s COG within the body’s base of support (BOS). When the human skeletal structure is in the ideal, standing position, the LOG passes from the crown of the head through the second sacral vertebrae (S2) to just in front of the ankle joint between both feet and falling perpendicular to the floor.
Another term heard in reference to gravity and structural balance and equilibrium is “stability.” Simply put, stability is defined as the amount of resistance or tensile forces produced by the nervous system to create enough internal force to offset the disturbance of the skeletal structure’s COG. Put another way, the stability of the human skeletal structure is achieved by creating balance and equilibrium that is affected by the position of the COG, the LOG and where it falls, the BOS, body mass, and friction. These then are all considered to be the “principles of stability.’
The base of support (BOS) refers to the area beneath the body that includes every point of contact the skeletal structure makes with the supporting surface. The body is balanced and stable when the COG is vertically within the BOS. If the COG falls outside of the BOS, the skeletal structure is less stable. Balance then can be defined as the body’s ability to maintain the LOG within the BOS while in a static position or while in motion. Therefore, balance is both a static and dynamic process. When thinking about the activities of daily living, it can be considered to be along a continuum going from static to dynamic balance.
With other factors being equal, keep in mind that the lower the COG the greater the stability of the skeletal structure. For instance when a person squats to improve stability, they do so by lowering the the height of the body’s COG above the BOS. That is why someone is instructed to squat when lifting something heavy. It gives them more stability.
The amount of resistance provided by the “force of friction” at the interface between ground and contact points of the skeletal structure contributes to stability. For example, a person standing or walking on a dry, sidewalk or pavement would encounter more friction and be more stable than let’s say someone doing the same on ice. Simply, the greater the friction between a surface and contact points of the skeletal structure, the more stable the body is.
The inclination of a surface too will affect stability while standing or walking. The greater the inclination like going down a ramp or walking downhill, decreases skeletal stability. Momentum, a property when the body is in motion and by virtue of its mass and speed will determine the length of time required for the body to come to rest in a static position affects stability.
Internal Forces
Thus far the focus has just been on the external forces affecting the nervous and skeletal systems of the body. Keep in mind the output of the nervous system in reaction to these external forces is what creates the position and motion of the skeletal structure. This reaction is not the product of one isolated part of the nervous system, but a number of its systems working together in “coordination or integration as a unit.” If you have been treated at my clinic, you know my favorite phrase used is, “everything is connected.”
Many of you in the past have asked, “Why the eyes?” Well, skeletal balance and equilibrium involves your visual system and eyes (vestibular-ocular reflex), vestibular system and the middle ear, and the body’s sense of where you are in space or proprioception. All this sensory input affects the output of your nervous system affecting the muscular and fascial tone creating enough tensile force to offset or cancel out the primary forces of gravity and ground reaction.
The Human Nervous System
This is referred to as, “central sensorimotor integration” and the major integrating factor is the human nervous system which includes both the central and peripheral nervous systems. Skeletal balance and equilibrium, an output of the nervous system, is often times taken for granted. But without it, you would find it difficult to walk across a gravel driveway or get out bed during the night without stumbling or worse falling. Whereas in my case when much younger, it would have been impossible to fly through the air on a pair of skis.
I have been called many things by my clients which I will not mention. Just kidding! But through the years I have been called a “muscle whisperer” or even a “muscle therapist” implying my expertise is working with the spinal cord and its muscle reflex action. That statement may be true, but it is only half the truth.
As the years have passed, I’ve come to the realization that I am working not only with the quick and immediate reflex action of the spinal cord affecting the internal, tensile forces, but also with the brain involving processing, integration, and memory which in the scheme of things takes longer. I know you have heard before the phrase “muscle memory” when exercising. You cannot talk about memory without talking about the brain. Memory is a system or process within the brain that stores what you learn during your personal life experiences to be used for future use.
I know this sounds confusing when I am working on your physical body with treatment, but while physical position and motion of your body is central to what I do, it is no longer my foundational focus. Instead my focus is more on the human brain and its processing, integration, output, and memory. Sometimes I refer to memory in the clinic as the “imprint”on your nervous system, but to put it another way it is the pathway or pattern most often used by your nervous system with the least amount of resistance.
Everything you have ever felt, experienced, or done in your life has been due to your brain function. At its most basic level, the complex firing rates and patterns of your brain determine who you have been or who you will become. Simply put, all your human life represents the changes in your nervous system and all that you are involves your brain because “you are your brain.”
Your entire existence , everything you experience such as the sights, sounds, touch, smells, tastes, and yes the position and motion of your skeletal structure is merely electrical firing of neurons that occurs within your CNS. Everything you experience in your life boils down to which neurons, which pathways are firing, when they are firing, and how often they are firing. I am talking about your own, personal, individual organization of the nervous system based upon the the sensory input, processing and integration, and motor output. That’s your life all summed up or cumulated into electrical activity through your nervous system over time.
During the many years of brain research there has been a gradual paradigm shift in how we look at the brain and its electrical activity. Contrary to popular belief, the brain does NOT stop developing after a certain age. Your brain is constantly learning, adapting, growing, and changing throughout your life. It is developing new neural pathways everyday and this continuous neural change is referred to “neuroplasticity.”
If your nervous system has the potential to change as is now established, then you can alter the neural pathways, the neural circuits that are causing your musculoskeletal pain. It doesn’t matter how old you are or what’s happened in the past. You can just throw out the old quote, “You can’t teach an old dog new tricks!” I have worked with clients as old as 97 and made changes with their nervous system that altered the position and motion of their skeletal structure and more importantly the perception of their pain.
Do not accept the phrase by doctors in treating your musculoskeletal pain, “It’s because you are older. There is nothing you can do to change it.” The neuroplasticity of the human nervous system just mentioned tells us otherwise.
I know this all sounds overwhelming, but despite its complexity, the human nervous system is organized in such an orderly manner that it helps you to understand what is going on within your body when it comes to musculoskeletal pain. Again, your nervous system has two main divisions: The Central Nervous System (CNS) involving the brain and spinal cord and the Peripheral Nervous System (PNS) involving the sensory and motor neurons or cells that transmit nerve impulses or electrical activity and the Autonomic Nervous System (ANS).
The Brain
Since my focus in the clinic has become more “brain based,” I will start my explanation of what happens within the nervous system loop of communication in finding skeletal balance and equilibrium with the brain. The brain is actually split into the “first or old” brain, which is the instinctual part that is primarily concerned with keeping you safe from threats during your life. In short, it’s about your survivability and keeping you alive. The “second or new” brain, on the other hand, controls your higher-order thinking, creativity, and logical decision making. Simply, your frontal lobe thinking that separates us from the rest of creation.
The Loop
To understand how your nervous system works, you have to come to the realization that it is designed in such a way as to communicate and function as a loop and within this loop there are four stages: Sensory Input, Integration, Decision, and Motor Output.
With sensory input, your spinal cord is dominant in taking information from various sources and sending the information to the brain to be processed. However, some of this input can facilitate reflexes at the spinal cord level with all this information none the less being sent up to the brain or so called “higher centers.”
Exteroception/Interoception/Proprioception
There are three categories of sensory input which include exteroception, interoception, and proprioception. Exteroception is the neural, sensory input from the external environment outside your body that usually involves the cranial nerves and the five basic senses of sight, sound, smell, touch, and taste. Interception, on the other hand, is the neural, sensory input coming from inside the body. It includes an awareness of your bodily sensations and feelings like heart rate, respiration, visceral function, and temperature. Finally proprioception which is the the sense of your body in space or the perception and awareness of the position and motion of your body. The sensory input from these different categories comes into the CNS at the spinal cord and is sent to the brain to be integrated and processed in different parts.
However as already mentioned, some of this sensory input will cause output directly from the spinal cord as in the example of the “patellar reflex” which most of us experience during a medical evaluation. This is an example of proprioception when a clinician taps your patellar tendon with a reflex hammer and the knee should automatically extends in what is referred to as a monosynaptic reflex arc.
Keep in mind that these spinal cord reflexes play a big part in the neural sensory input when talking about skeletal equilibrium and balance. But, more importantly there are many types of receptors and sensors that feed into the CNS including the proprioceptors, mechanoreceptors, baroreceptors, thermoreceptors, chemoreceptors, electromagnetic receptors, nocireceptors or pain receptors. These receptors feed information to the spinal cord and to the “higher centers” of the brain for processing and integration.
Processing and Integration
The processing and integration of the sensory input occurs inside different locations of the brain where certain input is localized. These include the occipital lobe for visual input, parietal lobe for spatial awareness, temporal lobe for the senses of smell, hearing, and long term memory, cerebellum for movement, coordination, and balance, and the brain stem and limbic system for the autonomic system which includes the sympathetic and parasympathetic divisions.
Then there is the frontal lobe at the front of your brain that controls your cognition or process of acquiring knowledge and understanding through your thoughts, life experiences, and senses. Also, an executive function because it is the major control center for attention and decision making. However its main function is in “inhibition.” That is because it prevents you from acting just on instinct with the sensory input coming from the “older brain” and pares down your reflexes to allow you to remain focused on the task at hand or what is really important at that moment in time. But it does even more controlling your voluntary movements of the body and extremities through what is called the primary motor cortex. That is because this part of the frontal lobe has ascending fibers running directly down the spinal cord to make your muscles contract because of your volition or decision.
The integration process is not innate, but has to be learned. An acquired skill where all different types of sensory information you experience are put together. It is like most acquired skills, the more you practice, the more trials and errors experienced, the better you will become at integration. Just look at the trials and error by an infant when first beginning to walk until they finally get it. The successful neural output of the human gait. Or what about learning things like fire and a hot stove are too hot to touch? An infant usually only has to do this once processing and integrating this sensory information so not to do it again.
Decision and Output
All these areas of the brain aforementioned are constantly working receiving information, processing and integrating so it can be interpreted and a decision made about how to act on the input. Keep in mind the decision and output stages of this loop are designed first and foremost with your survival in mind. “What a great design?” The brain fist needs to know if the sensory input it is receiving is safe and performance is secondary. This is the function of the “first or old brain” making a quick judgement on the input occurring at the subconscious level. The “second or new brain” will be involved only when necessary in order to make a more logical decision that takes more time.
Now that it has been substantiated that your brain’s primary job is your survival, its secondary job is performance which includes movement or output. Listen to what Dr. Daniel Wolpert, a medical doctor and professor of neurology at Columbia University has to say about this: “We have a brain for one reason only…that’s to produce adaptable and complex movements. Movement is the only way we have affecting the world around us…I believe to understand movement is to understand the whole brain. And therefore it’s important to remember when you are studying memory, cognition, sensory processing. They’re for a reason, and that reason is action.”
Simply put, your brain always wants to move. Think about this! When you were younger, you moved around a lot being in constant motion. Then as you have gotten older, you have found a nice, comfortable rut to settle into and move less and less. You become more sedentary. Because of this decreased movement, certain neurons and pathways in your nervous system begin to lose optimal function by way of a process called “transneuronal degeneration.” Simply like a phrase I will use in the clinic, “use it or lose it.!”
Most of your brain is dedicated to movement. Therefore, you need to move to drive the foundational and functional sensory and motor loop of your nervous system. It is as simple as you move, you get sensory input that is interpreted causing output, and then you move again and this cycle starts over.
Now within the output control of the brain, there are two primary parts: the “voluntary motor activity” and “reflexive stability.” Voluntary movement is controlled by the contralateral or opposite side of your brain so that the left side of your body is controlled by the right side of the brain and vice versa. Approximately 10% of the total brain output is dedicated to your voluntary movement. The other 90% of brain output is dedicated to creating reflexive stability ipsilaterally or on the same side of the body by activating a portion of the first or old brain called the pontomedullary reticular formation (PMRF).
The PMRF’s main job is in controlling your posture, setting the tone of your muscles, inhibiting sympathetic nervous system tone, and also inhibiting pain. All output from your nervous system whether it be pain, compensation, or perfect performance of an athletic skill, is the sum total of everything that occurs within your nervous system’s sensory and motor loop: you move you get sensory input which is then processed and integrated to be interpreted and decide the motor output; you move again and the cycle repeats over and over again. That is life!
While most physical therapists still focus mainly on the motor output, I have been using a more neuro, brain-based approach utilizing techniques to alter the sensory input by using the muscular and fascial systems of your body. As a result, I now consider myself more of an “input analyst.”
Most of you come to me with the generally stated desire to improve your posture and movement as well as manage your pain. You want to move, sit, and sleep without pain and feel stronger and more flexible. What is preventing you from achieving these goals is not foremost the motor “output” I used to emphasize, but rather it is the sensory “input” that affects your skeletal structure.
In our conversations about your musculoskeletal problems, I often will hear hear fear and anxiety about the symptoms whether it is your neck, shoulders, lower back, hips, knees, ankle, or feet. In your mind, I know you are afraid that you could have these symptoms for the rest of your life. That’s where I come in to alter your nervous system’s input so that the input is not interpreted or processed by your brain as a threat creating these emotions of fear and anxiety.
Remember, the more your brain is concerned with survival, the more likely you are to have outputs that prevent you from reaching your goals and causing the compensation of your skeletal structure that I see in the clinic. I know that because I experienced it when training for nordic ski jumping after my injuries. That fear and anxiety is real, I lived it. It becomes your reality.
My brain would not let me achieve the optimal performance of the athletic skill I trained so hard for until I could overcome the fear and anxiety. When looking at activities of daily living, your brain will not allow you to lift something heavy with optimal performance if your brain starts to assess that you may tear something. Your nervous system will shut you down because its main job is to protect you from harm. If you move too quickly and your brain assesses you may fall, it will shut you down!
The more the threat to you, the more likely the brain will produce the output of compensation that includes the pain, fatigue, inflexibility, dizziness, poor movement, poor balance, and headaches. The negative outputs of the nervous system I hear everyday in my clinic. These are all the protective outputs your nervous system creates in order to make the threat less and stop what you are doing to keep you safe and alive. After all, “survivability” is the main job of your nervous system.
Now don’t misinterpret what I am saying because protective outputs can be healthy like if you touch your hand to a hot stove and have the output of pain. Your nervous system alerts you and teaches you not to touch that hot stove again. But other than these instances, these protective outputs of your nervous system only get in the way of your life and performance.
Keep these things in mind when seeing me next time in the clinic or when you are seeing a medical doctor or some other allied health professional about your musculoskeletal pain. The key to treatment, no matter the technique, should be primarily to train your CNS and especially the brain to recognize your dysfunctional postural and movement patterns acquired over time that is causing pain. Then learn to work with these dysfunctional and dominant patterns imprinted on your nervous system and “alter the brain input.” That is why I want to become the best “input analyst” I can to help you get better and stay better throughout your life.
That is where I will end this article. Next month, I will talk more about these dysfunctional patterns of output by your nervous system and how I try to change them. Until then, BE SAFE, BE WELL!
Terry