To give a sense of our complexity, scientists estimate that there are >7 trillion nerves in the entire body. A 1 inch by 1 inch square box on your arm is estimated to contain 3 yards of blood vessels, 4 yards of nerve fibers, 100 sweat glands, 3 million cells, and 32 million bacteria. Numbers this large are almost unfathomable. While the exact number is not important, it speaks to the sophistication and complexity of the human nervous system.
The nervous system is responsible for two very important functions. First, it provides all of the sensory input to the brain- “that’s too hot,” “my arm itches,” and “my shoulder feels tight,” as examples. This raw data about the state of the body is translated into usable information in the brain. Second, the nervous system coordinates the movement of the body. These movements are both voluntary and involuntary, meaning we can choose to perform a movement or we reflexively move out of habit or for safety. Bending forward to pick up your groceries is a voluntary movement, and crossing your legs when you sit on the couch is an involuntary movement. Becoming familiar with these two nervous system functions is important for understanding how it directs our feelings, actions, and emotions.
From End to End
When thinking about the nervous system, I like to imagine the nerves as small roots of a tree that each connect back to a larger central root system. The nerves on the bottom of your toes run through the arch of the foot to the inner ankle, up the back of the calf and thigh, into the spinal column, and finally into the brain. In other words, almost all nerves travel from the body, into a specific region of the spine, and eventually arrive at the brain. As the nerves travel throughout the body, each one winds through the skin and muscles, around bones, and across joints. Just like the roots of a tree, our entire nervous system is connected; and therefore, responds as a single unit.
Each of these nerves communicate via special receptors that interpret temperature, vibration, pressure, body position, pain, and more. While there is plenty of variation in each individual’s anatomy, the general pathways are consistent for almost all people. For this reason, if you have tingling in your little finger, we know that somewhere along the nerve pathway is involved. Each part of this pathway- body, spinal cord, and brain- needs to be in balance to efficiently and appropriately pass information back and forth.
Tension & Compression
While the nervous system is highly resilient and adaptable, it is also very protective against injury. As a result, the nerves are highly sensitive to local changes in blood flow and oxygen. Normal, healthy movement is important for a well-tuned nervous system. Contrarily, nerves become less resilient with poor postural and training habits. Limited movement and imbalanced training only stimulates the nerve receptors in a small range of totally capacity. If something occurs outside of that range, the nervous system does not know how to respond, and the chance of injury increases.
Specific to movement and training, nerves are sensitive to tensile and compression forces. Tensile forces on a nerve can be compared to stretching a rubber band from both ends. A common posture that tensions the nervous system is prolonged slouching through the lower back while sitting. The slouched posture stretches the lower back nerves as it runs from the spine into the glute muscles. Compression forces- on the other hand- are any pinching (or narrowing) forces on the nerve. Similar to how a blood pressure cuff shunts blood, certain postures or movements compress our nerves. For example, compression from a blood pressure cuff is a relatable example. You can tolerate a blood pressure cuff at a low intensity for a very long time. As the cuff gets tighter, the duration of time decreases. The nerves register the increased compression and send signals to the brain about potential threat. The result is often tingling, temperature changes, and a feeling of muscular agitation. The key is remain strong and mobile through a wide range of tensile and compression forces.
All systems in the body strive for an internal state of equilibrium, which is known as homeostasis. Since the nervous system is the command center of the other systems, maintaining equilibrium is especially important. Both physical and mental stressors significantly impacts the ability to regulate the nervous system. When a nerve reaches its capacity for tolerating stress, nerve related symptoms will present. Symptoms can range from numbness and tingling to itchiness, and even to muscle atrophy in more pronounced cases.
Having had intermittent nerve pain in my right arm, this concept is intimate to me. My nerve pain presented as itchiness in my elbow during the middle of the night. The itchiness was so intense that I would wake up scratching my skin raw. After becoming familiar with the pattern, it became apparent that my nerve symptoms were largely related to prolonged sitting at the computer, a lack of physical exercise during these time periods, and poor sleep habits. No single factor induced the nerve pain, but rather the cumulative stressors eventually led to nerve irritation. While I primarily experienced itchiness, each person’s nerve symptoms will depend on the specific pathways that are perceiving stress.
Low Quality Input= Low Quality Output
In this post, we have discussed how the body sends input to the brain, how the brain translates this data into usable information, and how mental and physical stress impacts the nervous system. This information provides the necessary framework for understanding how to maintain a healthy and responsive nervous system. Additionally, it highlights the importance of both the input from the body & the output from the brain. In other words, the quality of input influences the quality of output. Our nervous system is strong, complex, reslient, and adaptable. The more we use and test our bodies, the better understanding we will have of our nervous system!
The explosive start of a swim race requires a 0 to 100% effort at the beep of a horn. From the starting blocks, the swimmer's legs essentially perform a maximal broad jump while the arms shoot overhead into a streamline position. Power, reaction speed, mobility, and aerodynamics are several of the necessities to a strong start, and a strong start is essential to a successful race. The physical and mental preparation before a race is highly important.
For many swimmer's, part of this race preparation involves swinging their arms in circles and slapping their arms around their body. These large warm-up movements are so common that even Michael Phelps has a video promoting his impressive #MPbackslap. So why do swimmers perform these pre-race motions?
Priming the Tissues
Athletes from all sports have their signature warm-up movements. These movements are specific to the sport, but general in their functional intention. For swimmers, the specific purpose of the backslap is to activate the shoulder and core muscles in a quick, explosive, and springy nature. Generally, the functional intention is to prime the tissues in a similar fashion to how they need to work during the race.
Slapping the arms around the body wakes up all the muscles from the powerful Latissimus dorsi muscle down to the tips of the fingers. The vibration of the slap jump starts the nervous system and sends blood flow and oxygen to the arms. Additionally, the backslap is a plyometric movement for the upper body. The quick stretch and release primes the upper body's connective tissues, such as the tendons. Similar to how a track and field sprinter jumps in place before a 100-yard dash, a swimmer performs the backslap to mobilize their tissues and find their tempo before hopping off the block.
Take Home Advice
Listen to Your Body
Many factors play into a successful warm-up, but the most important is listening to how your body feels.
-Jim Heafner PT, DPT, OCS
Owner, Heafner Health Physical Therapy
Learn how to determine when it’s safe to continue a workout and when to stop exercising if pain arises.
Until recently pain has been thought to be an indicator of the amount of tissue injury present in the body. The belief is that a high amount of pain equates to a serious injury, and a small amount of pain equates to a minor injury. However, through extensive research, we now know that pain has surprisingly little correlation to the amount of tissue damage present. For example, it’s estimated that 40% of people without any low back pain have at least one “bulging” disc on a lumbar spine MRI. Instead of pain acting as a barometer for tissue damage, it should rather be thought of as an alarm system, warning you about actual or potential threats to continuing a workout.
When is it Safe to Continue Exercising?
Since pain does not equate to tissue damage, does that mean you can exercise past the point of pain without any consequences? No pain, no gain…right? Not quite! As mentioned above, pain is an alarm system meant to alert you to potential danger. In the case of exercising, the danger may be caused by a specific movement or a specific weight machine. However, just as alarms can misfire, your internal protective mechanism can do the same. Factors such as fear, stress, anxiety, lack of sleep, overactivity, poor nutrition, and many others can influence your alarm system’s perception of danger. When exercising, do not underestimate the importance of these factors.
In my clinical practice, I always tell patients, “respect the pain and evaluate the symptoms you are feeling!” If the pain persists, stop exercising. If the pain decreases by modifying the exercise, warming-up the muscle, or simply desensitizing the movement with a few repetitions, it’s likely okay to continue exercising!
Sharp pains may indicate that a muscle, ligament, or joint is actively getting injured or overstressed. These pains quickly catch our attention because they travel along fast-moving nerve cells to warn us something is not in balance.
Nerve-related Numbness or Tingling
Numbness, tingling, or sudden muscle weakness may indicate that a nerve is getting angry because the normal amount of oxygen around the nerve has been altered. In my book, Making Sense of Pain, I discuss how the nervous system is highly sensitive to changes in oxygen levels. The nervous system weighs only two percent of our total body weight yet requires 20 percent of our total oxygen supply. When a nerve becomes tensioned or compressed, its oxygen flow is altered, often resulting in perceived numbness, tingling, burning or aching.
Finally, pain that continually increases is a good reason to stop a workout. Increasing pain may indicate that the aggravated tissue is repeatedly getting over-stressed. This can lead to an overuse injury, which could require you to stop exercising for several weeks.
Written by: Dr. Jim Heafner PT, DPT, OCS
Originally written for the IDEA fitness blog with contributions from OPTP.
If you have ever experienced lower back pain, there is a good chance you can recall some very specific details about the experience. For example, you may remember where you were, what you were doing, and how intense the pain was for 24-48 hours after the injury. People often remember this experience (and those similar to it) because the human brain prioritizes experiences that require a significant amount of attention. On the same list of significant experiences (even though the emotional response is different) would be watching the birth of your child, seeing a beautiful sunset, getting married, etc... Any experience that overwhelms the senses (sound, sound, touch, smell) is likely to be remembered because of the intense emotional association.
If you are currently experiencing low back pain or worry about having low back in the future, this article will help you better understand pain and quickly manage any symptoms that may arise.
Understand Your Pain
At this point, you may be thinking, "Leave the emotions out of it...I strained my back muscle, not my brain!" While the low back muscle may be the injured tissue, it is necessary to look beyond the muscle to fully understand why the magnitude of your pain. Pain, by definition, is an unpleasant sensory and emotional experience, unique to every individual, associated with actual or potential tissue damage. Therefore, it is impossible to seperate the pain from the emotional response.
Regarding low back pain, it is important to know that pain is rarely caused by a serious medical issue (such as a fracture or cancer), that would require urgent medical attention. The majority of lower back pain (>70%) is due to tissue sprains and muscle strains, which respond well to rest, easy exercise, and education. For this reason, X-rays and MRIs are not indicated as they often do not correlate with pain.
Learn the Back Facts
Get Moving (Gradually and Easy): The Goldilocks Principle
The story of Goldilocks is about finding the right fit, and I can tell you that little blonde girl was onto something! The idea of not too much, not too little, but just the right amount applies to many facets of life. Gradually increasing activity to improve pain and gain strength is certainly no exception. The human body gets stronger and more resilient through a process of gradual, progressive exposure and strengthening. To get stronger, you slowly and steadily lift heavier weights over time. If you lift too much too soon, you’ll become sore, or worse, injured. However, if you don’t lift enough weight to challenge your body, you’ll never get any stronger. The exact equation of not too much, not too little, but just the right amount is unique to everyone and will change over time as your body matures.
As you are recovering from a lower back injury, start moving slowly in small ranges of motion. As your fear decreases and ability to move increases, gradually increase the range of motion and demands of the movement. For example, in the progression below, I show how to gradually improve bending forward.
Don't Neglect Other Areas of Your Health
If you are experiencing pain, it is easy to blame the pain solely on a physical or structural problem. With that being said, I am not discrediting the tissue injury that may have occurred. After a traumatic event, such as a car accident or lifting injury, inflammation and other chemical signals (redness, warmth, swelling) can be observed. However, since you just learned about the complex nature of pain, I urge you to think about other areas in your life that may impact your pain response. In these moments, I always tell my patients to 'respect the healing process.' This includes focusing on good sleep and rest, reducing or minimizing stress, eating a well balanced diet, and performing gentle movement (as discussed above). In the picture below, I outline many of the areas that impact your experience of pain.
Remain Positive and Optimistic
Finally, mindset is key! Following an injury, our brains naturally revert to the worst case scenario. Fear, anxiety, worry, and other negative emotions flood your mind. While listening to these emotions is important in the moments of actual threat, the majority of these fears are not accurate. The reality is that you will most likely return to your normal life in a matter of days or weeks. In the midst of pain, having a mantra, such as "my back is strong and health," can help slow down the negative emotional response. By mindful repeating or thinking optimistic thoughts, you will strengthen the brain connections geared toward optimism and happiness.
Jim Heafner PT, DPT, OCS
Heafner Health Physical Therapy
If you are looking for low back self treatment strategies, click here!
Your muscles are a very important organ system in the body, as they play the role of the workhorse in every movement you make. However, you can’t forget that the muscles are at the mercy of the governing nervous system. Everything you feel is actually an experience created by your brain and nervous system. For this reason, muscle memory is somewhat of a misnomer! Muscle memory is a term used to describe how our nervous system and brain work together to build strong connections and develop movement habits for specific activities. For example, if someone repeatedly practices throwing darts at a target, they will most likely improve their accuracy over time. While the fingers and forearms feel the movement, the 'memory' is really encoded in the brain. At the same time, if someone postures their muscle is a certain position for working for multiple hours each day, the movement or posture will remember this position.
The nervous system tells the muscles how to act and what to feel. If there’s tightness, stiffness, guarding or pain in a muscle, it’s often because the boss is unhappy and the employees are just carrying out the boss’ orders. For example, think of the last time you exercised when you were tired, stressed or hungry - it probably wasn’t a great workout. If the boss (your brain and nervous system) is in a bad mood, the employees (your body) feel the strain. Allowing the boss to calm down or letting the boss rest can reduce stress on the employees. In response, the boss can stop the overbearing micromanagement, which is causing the employees to revolt.
Following an Injury, Your Muscle Memory is Altered!
While you do not remember this learning process, it occurs through countless hours of practice and repetition. As a new father, I see these repetitions happening in my baby daughter each day. While my daughter is not picking up a cup of water yet, she is starting to see objects, identify her hands, and reach for the objects. Over time, each piece of the puzzle will come together and her 'muscle memory' will be encoded.
In your own body, think of this “muscle memory” as an internal GPS that’s aware of every movement you make. When an injury occurs, your internal GPS is often reprogrammed to make you move in different ways. With an injury, there can be different messages sent between the brain and the muscle, meaning your “muscle memory” has been disrupted. After some time, your internal GPS may no longer be able to accurately identify certain roads on your body’s map. While the injury is healing, the brain and body often coordinate alternative, compensatory strategies for certain movements like a limp, awkward bending mechanics, stiff movements, or limited range of motion. These protective phenomena are much like how a GPS detours to an alternative route because of a road closure.
The movement detours may feel uncomfortable or less efficient, much like driving down a heavily trafficked and overcrowded street. This is because your brain isn’t familiar with the detour, which may place new or different stresses on the system. By building new and confident movement strategies, you can experience minimal issues while the main road is being repaired. However, once the body’s healed and the route’s obstructions are cleared, it’s important to return to the main road without fear.
Keys Points and Takeaways
Jim Heafner PT, DPT, OCS
Heafner Health Physical Therapy
Boulder, CO 80301
After being fouled in a basketball game, players find themselves at the free-throw line to take a shot. Overall, the shooting motion looks relatively similar among players, but there are small differences that make each player’s technique unique to them. If you watch closely, you may notice that each player has their own stance, pre-shot routine and shooting mechanics.
A professional basketball player spends countless hours practicing this shot and developing a routine that makes them feel comfortable and confident. There’s a saying in neuroscience that’s applicable here: “Nerves that fire together, wire together.” With practice, their brain creates a crisp and fine-tuned program for shooting the free throw, and repetition makes approaching their shot second nature. The less thinking required for the actual shot mechanics, the less they’ll try to make small adjustments in response to stress, pressure, fatigue and fear that could interfere with making the shot. This ability of the brain to adapt, change, rewire and refine is referred to as neuroplasticity.
The repeated experience of pain is fired and wired together similarly to practicing free throws. The more you experience, think about and focus on pain, the more you can improve your brain’s ability to activate that pain program. Just like the way practice refines the shooter’s skills, the more you expect and believe pain will occur, the more likely pain will actually occur.
Want More Analogies Similar to This One?
For this analogy and 50+ others, I highly recommend checking out my new book with co-author Jarod Hall. The book is titled Sticks and Stones. It is a collection of analogies & stories to help people gain a deeper understanding of the complex nature of pain. With each analogy and metaphor covered throughout this text, you’ll find multiple stories that help relate the complex topics of pain, tissue breakdown, posture and more. Through each story, you’ll notice a strong focus on the power of language.
Jim Heafner PT, DPT, OCS
Heafner Health Physical Therapy
Sciatica, carpal tunnel, neuropathy...these words all have scary connotations! Fortunately, the majority of nerve-related symptoms are not threatening. Each of these diagnosis' are a symptom describing the specific tissue that is irritated. They do not address the underlying issues that cause the pain, nor how to treat it.
For example, if someone comes into Heafner Health with wrist pain, and I identify they have carpal tunnel syndrome, I know the median nerve is receiving extra stress. While the compression or tension may be at the wrist (where the person is experiencing pain), the issue could be ANYWHERE along the nerve- in the neck, the shoulder region, forearm, or the wrist. Since the nervous system is a continuous structure, providing education about the nervous system and treatment anywhere along the nerve can result in a successful outcome! For this reason, understanding how nerves move and work can make a huge impact if you are experiencing pain.
Nerves are like Garden Hoses
The nervous system functions similarly to a garden hose. Just as the garden hose delivers water, our nerves are responsible for feeding the muscles, joints, skin and other soft tissue. If the garden hose becomes kinked or compressed, the amount of water flowing through the hose is reduced. Your nerves respond in a similar fashion. If nerve pressure or irritation rises to a certain level, blood flow to the nerve and electricity through the nerve, known as the axoplasmic flow, is interrupted. This alters the amount of nutrition through the nerve and leads to an aggravated state.
The nerve’s response to reduced nutrition can be a vague array of symptoms, most commonly described as numbness, burning, heaviness or tingling.
To improve nerve nutrition, you must improve the flow of electricity and blood in the nerve. This is accomplished through gentle and specific movements and exercises. Fortunately, just as the garden hose returns to full function when the kink is released, nerves also respond favorably to the decreased compression and increased movement.
-Jim Heafner PT, DPT, OCS
Heafner Health Physical Therapy
Recently, I have been fascinated with the subject of sleep, specifically the positive and negative health benefits of sleep.
The research is overwhelmingly in favor of getting more sleep than not. According to the National Sleep Foundation adults need 7-8 hours of sleep each night (1). The good news: I am finally on board with this idea! I have dropped my old machismo ideations that I can force my way through fatigue. I know longer view exhaustion as an admirable, but rather an indication that my health is being compromised. The bad news: This is unfortunate and ironic timing considering I had my first child 6 days ago...! Regardless, I am finally prioritizing sleep.
On my journey of learning about sleep, I ran across a fascinating story about medical residencies and sleep deprivation.
More and more physical therapists are attending demanding residency programs! The physical therapy residency training model appears to be largely based off our close friend in the community: medical residents.
In 2013, I graduated from the Harris Health System Orthopedic Residency program in Houston, Texas. Our program was tough, but our director, Dana Tew, did an excellent job mentoring my fellow residents and I on all aspects of life. We worked extremely hard at the clinic, but there was at least the opportunity of a work-life balance. Dana, who is also owner of the OPTIM Manual Therapy Fellowship, understood that our success and efficiency in the clinic directly correlated with our ability to sleep and manage stress outside the clinic.
As I was going through my residency, my older brother, Tom was completing his general surgery residency. I recall him spending 30+ hours at the hospital on a regular basis. These long hospital shifts often had little (if any) sleep! Hearing this information, I thought to myself, "I would certainly rather have a surgeon at the beginning of a 30+ hour shift than the end. It has to be unsafe to perform a fine motor task that requires mental acuity after intense sleep deprivation."
Who instituted these unattainable demands of high work and low sleep for people who need to in prime mental health to help others? The story is a quite interesting one!
I would regularly ask myself, "Who instituted these unattainable demands of high work and low sleep for people who need to in prime mental health?"
1. National Sleep Foundation’s sleep time duration recommendations: methodology and results summary Hirshkowitz, Max et al. Sleep Health: Journal of the National Sleep Foundation , Volume 1 , Issue 1 , 40 - 43
From professional athletes to musical entertainers and beyond, high-energy performers execute complex motions with relative grace and ease. Whether it’s LeBron James dribbling down the court or Bruno Mars dancing on stage, their coordination and precision are due to the incredible motor control and movement pattern memory they’ve gained through countless hours of training. However, these well developed movement patterns can be altered in the presence of injury, fear, and more!
At my clinic in Boulder, Colorado, I was recently working with a middle-aged man who was experiencing low back pain when lifting more than 40 pounds from the ground to the trunk of his SUV. This pain was interfering with his ability to perform work tasks as well as household chores. Within 3 treatment sessions, he was able to mimic the mechanics of the lifting motion without any pain. During visit 5, he performed the 40 pound lifting task repeatedly pain free. However, the following day at work, his pain immediately returned when attempting a lift.
The above example, demonstrates the complexity of pain. This client objectively demonstrated proper strength and mobility to perform the lift in clinic; yet, when attempting the lift at work, the pain returned. When I asked him about the experience he said, "I don't know why it hurt at work...I felt tense as if my muscles were protecting me from the movement...I was anticipating the pain...Since I was injured at work, the lift scared me." At this point, I reminded him of the many factors, including fear, that can impact his experience of pain.
"Fear and pain have a very intimate relationship"
Martial artist and actor Bruce Lee illustrated this idea beautifully: “You must be shapeless, formless, like water. When you pour water in a cup, it becomes the cup. When you pour water in a bottle, it becomes the bottle. When you pour water in a teapot, it becomes the teapot. Water can drip and it can crash. Become like water, my friend.” Water flows freely and fearlessly. Water doesn't stiffen or guard itself for protection. Water is smooth and fluid. Water is powerful. When learning how to move out of pain, you must challenge yourself to relax and allow your body to become like water!
While this may sound funny or unrealistic, it is important to learn how to relax with movement. For precise movement to occur, certain muscles must activate, while others simultaneously relax. Practicing the ability to move without stiffness can bring awareness to the movement and create learning opportunities that strengthen the connection between your brain and muscles.
When dealing with pain, do not forget about the contextual factors! Practice and repetition of movement will decrease the protective response from your nervous system and improve the mind-muscle connections!
Dr. Jim Heafner PT, DPT, OCS
Heafner Health Physical Therapy
If you found this post interesting, check out the book Sticks and Stones written by Dr. Jarod Hall and myself! The ebook contains 50+ analogies and stories pertaining to pain and movement!
Sticks and Stones will officially be available in early June 2018 at our site: theraPTeutic alliance.
Pre-order the book at the lowest price today by using the promo code: WORDSMATTER
I was recently working with someone who had neck pain after a mountain biking accident. During the evaluation, he reported hitting his head on the ground and experiencing a concussion during the accident. He stated "I am having difficulty remembering recent events and multi-tasking is near impossible! It's extremely frustrating!." Performing higher level tasks was easier in the morning and became progressively more challenging throughout each day. Additionally, he reported the desire to take naps throughout the day. When he questioned why his brain felt exhausted, I told him "It is because your brain operates much like a battery."
(This text is adapted from "Sticks & Stones," a book by Jarod Hall PT, DPT, OCS and Jim Heafner PT, DPT, OCS. "Sticks and Stones" is in the final stages of development. Final versions of the text to be released to public in May 2018. Please reach out if you are interested in learning more information!)
If you have persistent pain, recently had a surgery, or an injury (such as a concussion), your brain may be working in overdrive! In each of these scenarios it's not uncommon for patients to report that their brains feel tired early in the day, that they have trouble doing complex thinking tasks such as math, and even mix up their left from their right! Why does this happen? In situations like this you can liken your brain to a battery. This idea can be thought of in two separate ways.
1) You start each day at 100%, but quickly drain the battery each day