Explaining Pain: The Neuroscience of Pain-Free Training

The Z-Health Approach to Pain & Performance Barriers

Concept #1 – Understand that pain is produced by the brain.

Many people, physicians, therapists and trainers included, are still struggling with what is now an undisputable fact – that pain perception is produced by brain activity. Unfortunately, the cultural beliefs surrounding pain still tend to focus on pain as a reliable source of information about what is happening in the body. This is a false assumption and the leading cause of ongoing pain for most people. One of the most important phrases to remember comes from Dr. Karel Lewit who always states, “He who treats the site of pain is lost!”

Concept #2 – Pain is produced when the brain perceives that danger to body tissues exists and ACTION is required. Pain should then be seen as an ACTION SIGNAL.

The leading pain society in the United States, the International Association for the Study of Pain, currently uses this classical definition of pain:

“Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”

Unfortunately, this definition fails to adequately describe the true purpose of pain, and as a result can confuse the real issue. While pain IS an unpleasant experience its main goal is not to simply be unpleasant or attempt to signal the body about damage. Instead it is primarily a Danger Signal which should prompt Action.

Concept #3 - Because pain is a part of the survival system, ANY THREAT, can be interpreted as pain.

One of the most powerful concepts to come out of the Threat Neuromatrix approach is that virtually any stimulus can create pain if the brain interprets it as threatening. When you understand this concept, it will forever revolutionize your understanding of the multi-faceted event that is pain.

The brain can produce a pain signal in response to any stimulus or event that threatens your survival. Whether that event is emotional, physical, or even spiritual, if your brain perceives a threat to your ongoing survival there is a possibility that you will experience pain or a noxious event of some kind.

Concept #4 - Pain is individual.

Life experience has shown each one of us that people respond very differently to what appears, from the outside, to be the exact same stimuli. In other words, two individuals struck with the same amount of force in the same place will often have two very different internal experiences of that event. Modern pain research points out the fact that there are many different factors that determine what types of and when stimuli are painful for each individual. Some of these factors are:

  • Context – In what situations does the athlete experience the pain? If the pain is always present when moving while seated, changing the context and performing the movement while standing and talking with a friend may alter the pain.
  • Posture – If the pain always accompanies standing movement, the same movement could possibly be performed pain-free while seated or lying.
  • Competing Stimuli – Performing movements utilizing different visual or vestibular positions may alter the pain experience.
  • Emotional State – An athlete may experience less pain while listening to his favorite music versus when he is angry.
  • Visualization – Imagining that the movement is pain-free prior to performing it can alter the pain event.

At a basic level, this is a beautiful, ongoing real-life example of how the Threat Neuromatrix actually works. It helps us understand that pain is an EVENT that is based on the athlete’s perception of that event. As a result, altering this perception of the pain event can have long-term consequences in either improving or worsening their pain experience.

At this point, the main question becomes, “What can/should we do about it?”

 

Z-Health Pain Relief Strategies

Concept #1 – Make Pain-Free Training a Requirement

This is a simple, but crucial concept, that as a coach you must embrace. We must teach our athletes that practicing being in pain improves their ability to be in pain! As a result, we want to teach our clients to move with pain-free precision to maximize their life-long capacity.

Concept #2 - Reduce the Threat Level

Based on the previous discussion you should be comfortable with the fact that the first aim of pain reduction must be to decrease the amount of, or neural perception of, threatening stimuli. Remember that pain (or poor movement and performance) are danger/action signals in the body that result when the CNS feels threatened. The primary initial goal in working with your athletes must be to decrease the amount of threatening input/stimuli that their brain perceives. There are two primary means to accomplish this in the Z-Health® approach:

A. Alter the Signals

This term, which forms the basis for much of the beginning and intermediate approaches in Z-Health® refers to the need to maximize correct neural signaling from all parts of the body to the spinal cord and brain. Improper or disturbed mechanoreceptive input from body tissues makes high threat levels virtually inevitable.

In addition to working at the joint level, it can also be important to assess and improve the signals reaching the brain from both the visual and vestibular systems. Both of these systems are extremely vital to the body’s survival systems, and as a result, have a tremendous impact on pain perception. Just as in the proprioceptive system, disturbed signals from either the visual or vestibular system can result in painful symptoms.

  • Emphasize mechanoreceptive-specific movements. (Move Joints First!)
  • Decrease local negative arthrokinetic reflex activity.
  • Alter habitual movement speeds.
  • Address biomechanical force transmission issues to decrease the threat level associated with basic movement patterns such as gait.
  • Change postural inputs.
  • Alter visual and vestibular inputs.
  • Increase required visualization of movements and develop enhanced proprioceptive awareness.

B. Alter the Interpretation – Think Neurologically NOT Structurally!

The primary route for most trainers in this arena is both simple and complex: education. Remember that each individual athlete’s perception of their situation determines their pain levels. For many athletes the fear of injury, re-injury or long-term disability actually sensitizes their brain to increase their perception of pain. This must be dealt with carefully and systematically for best results.

The main goal here is to help your athletes understand that PAIN DOES NOT EQUAL INJURY!

This requires that we help them understand that they are working from an incorrect model through no fault of their own. It is very important here that you use care in communicating what you believe to be the cause of their pain. Remember, if you always return to explaining their pain via a structural explanation, this is what they will latch on to.

 

Pain as an Action Signal – Background Information

The question that we need to remember to ask ourselves about EVERY PAIN COMPLAINT is “Why does the brain believe that it is in danger?” The answer(s) to this question will give you a path to follow…

 

Classical Pain Basics

In the words of Albert Schweitzer: “We must all die. But that I can save him from days of torture, that is what I feel as my great and ever new privilege. Pain is a more terrible lord of mankind than even death himself.”

To be as efficient and effective as possible as a movement educator, it is essential that you have a strong understanding of the basic neurophysiologic mechanisms of pain. Developing your knowledge and understanding of what pain is, how it occurs, and how it can be dealt with is vital.

To begin, let’s look at the classic definitions of pain provided by the International Association for the Study of Pain (IASP):

“Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”

From this definition, the IASP then subdivides pain into two primary types:

  1. Acute pain is the normal, predicted physiological response to an adverse chemical, thermal, or mechanical stimulus associated with surgery, trauma, and acute illness. It is generally time-limited…”
  2. Chronic pain is a pain state which is persistent and in which the cause of the pain cannot always be removed or is difficult to treat. Chronic Pain may be associated with a long term incurable or intractable medical condition or disease.”

From this humble beginning, it becomes possible to add in more distinguishing characteristics about the various types of pain. The IASP has a textbook that covers over 30 different “types” of pain, and adds many other pain classifications as well. This system is based on the various tissues involved and the brain areas impacted. While this detailed approach has great value, on a day-to-day basis as a movement coach, it is probably more useful to begin this process with a simplified paradigm.

As you can see, this chart breaks pain down into two primary categories:

  1. Pain arising from nociceptive activity in the body, and,
  2. Pain that is non-nociceptive.

Nociceptive Pain

Nociceptive pain is pain that is driven by the activation of nociceptors in body tissues. It follows a distinctive path characterized by six primary steps:

Transduction – This occurs when an imminent or real injury occurs that stimulates nociceptive activity. Normally, this means that there have been thermal, chemical or mechanical stimuli applied to the sensory nerve endings of peripheral nerves. The nociceptors then translate or transduce this stimulus into electrical signals. If these electrical signals are strong enough to reach a certain threshold, this triggers an action potential, which starts the process of sending information to the CNS. As some authors have indicated, this is like lighting a fuse. While it may require some effort to light a fuse, once it is lit, the flame (or in this case the electrical signal) progresses along the length of its course unless it is somehow interrupted.

Inflammation – At the same time that the transduction process is beginning, local chemical changes are occurring at the site of the “injury”. Damaged or irritated cells release inflammatory substances that increase sensitivity to pain. Some of these chemicals are: prostaglandins, substance P, bradykinin, serotonin, and histamine. The release of these substances makes the area red, swollen and hypersensitive to pain. When this occurs, normal stimuli can now create pain. This is called allodynia. Sunburn is a good example of this phenomenon.

Conduction – Once the above two steps are in progress, the nerve signal is conducted along nerve fibers via action potentials along neurons. Sodium and potassium ions play a large role in this process as the sodium causes neuronal deplorization to occur and potassium restores a normal electrical charge. Nociceptive conduction, particularly in an acute injury, is carried out by A-delta fibers and C fibers. Interestingly, A-delta fibers carry sharp, well-localized pain sensations, while C fibers carry poorly localized burn and ache sensations around the area of injury.

Transmission – As one nerve conduction pathway ends, neurotransmitters must now transmit the original nerve signal across the synaptic gaps separating them. This is carried out by a variety of neurotransmitters including: glutamate, norepinephrine, serotonin, dopamine and others. Nociceptive signal transmission takes place in three distinct areas:

  1. Between the nociceptor and the dorsal horn of the spinal cord.
  2. Between the spinal cord and the thalamus and brainstem, and
  3. Between the thalamus and the cerebral cortex.

Many painful conditions can be traced to inappropriate activity at one of these three transmission sites.

Modulation – This refers to the adjustment of pain intensity carried out by the nervous system’s antinociceptive system. As everyone knows, the pain of an acute injury often fades within seconds or minutes. Based on tissue healing times, the injury is certainly not “healed” at this point, yet the pain fades allowing the body to return to more normal function. As Whitten, etal, write in their article Treating Chronic Pain: New Knowledge, More Choices (The Permanente Journal/ Fall 2005/ Volume 9 No. 4) this is a perfect example of the Melzack and Wall Gate Theory:

“One way to conceptualize this pain inhibition is the Gate Theory, first introduced by Melzack and Wall. Nerves are analogous to telephone cables: Both carry many types of calls or signals, but the total number of these carried at any moment is limited. Checks and balances built into the system help triage those signals. For example, if you hit your thumb with a hammer, rubbing the injury decreases pain because rubbing generates inhibitory signals that “close the gate” to the pain. An intense level of pain for a short time produces stress-analgesia, a short-term protective mechanism whereby the limbic system inhibits pain signals within the spinal cord. (On the battlefield, for example, a soldier may not feel a wound until after fighting stops.) However, the spinal cord is excited by prolonged stimulation of the limbic system by either stress or pain, and this prolonged stimulation can produce hypersensitivity to pain. Patients with chronic pain have reduced pain thresholds and therefore feel pain more intensely. Pain is diminished by factors which “close the gate” and is intensified by factors that “open the gate.” Medications, emotions, behaviors, and thoughts both open and close the gate by affecting transmission and modulation.”

Here is a table that describes from a medical perspective some of the things that can “open” or “close” the pain gate.

Factors that Close the Pain Gate

Factors that Open the Pain Gate

Physical

  • Movement
  • Heat/Cold
  • Massage/Mechano Stim
  • Comfortable Environment/Clothes/Furniture

Physical

  • Inactivity
  • Poor Sleep

Chemical

  • Diet – Anti-inflammatory
  • Supplements
  • Drugs

Chemical

  • Poor Diet
  • Inflammatory Food Reactions
  • Nicotine

Behavior

  • Relaxation
  • Humor/Laughter
  • Pleasurable Activities

Behavior

  • High Stress Environments
  • Difficult Relationships
  • Isolation
  • Worry

Emotions

  • Optimism
  • Focus
  • Realistic Goals

Emotions

  • Catastrophizing
  • Hopelessness/Depression
  • Anger
  • Focus on Pain

Structural

  • Corrective Exercises
  • Postural Correction
  • Surgery as Necessary

Structural

  • Postural Abnormalities
  • Trauma
  • Surgery or Post Surgical Issues

 

Perception – The last step in this nociceptive process is perception, or how the pain control centers of the brain interpret the signals that reach them. Pain enters the brain through the thalamus which then routes the signals to different regions of the brain involved with sensation, motor responses, emotions, behavior, stress and autonomic nervous system activity. Needless to say, these interactions are very complex, but the sum total defines the perception of pain. Research shows that hypersensitive people have more activity in the areas of the brain primarily responsible for pain perception, whereas, distracted people manifest less pain center brain activity. The short story here is that the best way to feel more pain is to focus on it! Unfortunately, focusing on the pain can lead to a vicious cycle impacting on all aspects of the clients’ functioning.

Non-Nociceptive/Chronic Pain

Conversely, non-nociceptive chronic pain offers an entirely different picture. It begins with changes in what are known as NMDA receptors that lie in the cleft between neurons. When an initial pain stimulus goes on too long, these NMDA receptors become sensitized, which triggers a cascade of events that leads to CNS hypersensitization. This is referred to in the literature as “central windup”. As this process kicks in, NMDA activation alters the balance of neurotransmitters, changes the firing threshold of nerves, and induces synthesis of different gene proteins, among other things. All of this together leads to:

  • The firing threshold of surrounding nerves is lowered which produces hyperalgesia or excessive pain sensitivity.
  • Non-pain nerves begin to fire and carry pain messages.
  • The threshold of opiod receptors is increased which makes endorphins less able to control pain.
  • Threshold sensitivity to catecholamines is lowered, thereby facilitating transmission of pain signals.
  • The pain fields spread to adjacent neurons in the spinal cord. This leads to non-anatomic pain and symptoms. Usually this means that uninjured areas of the body close to the original injury begin to hurt; then as additional nerves are recruited, areas increasingly further away become painful.
  • All pain perception increases making it seem more severe.

As Whitten, etal, point out:

“In the short term, these changes allow healing by forcing protection of the injured area. “Windup” usually resolves as the injury heals; in some patients, however, these changes persist. The more severe the pain and the longer it persists, the more likely that the change will become permanent.  We do not yet know the exact combination of pain severity, duration, etiology, and genetic predisposition that leads to chronic pain, but one important conclusion is clear: Inadequate pain control increases the likelihood that pain will become chronic.

 

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