Last weekend I took a workshop from Jules Mitchell, MS, an exercise scientist and yoga educator. It was titled “The Science of Stretching: Biomechanics and Neuromechanisms” and went into the latest research on what is REALLY happening at the cellular level when you stretch a muscle. The implications for these findings are fascinating and worthy of many blog posts. Good thing Jules has a blog! Not to mention students who also blog!
One topic that came up frequently in the seminar was pain. It turns out that pain is very closely tied to movement, or lack thereof, but not necessarily in the ways you might assume. I’m still processing all of the earth-shattering information presented in class, but I’m so excited about it that I wanted to share a few points that really stood out for me.
Before I go on, I should say that another thing that was emphasized in this class is that a reductionist view of health and the human body is not always useful. The ideas that I’m about to mention just barely scratch the surface of a new and exciting way of looking at pain, and are not even close to being the complete story. Also, for the most part these thoughts are my interpretation of someone else's interpretation of the research, as well as my own speculations on the subject. But they’re still really exciting to think about (at least in my opinion)!
And FYI, the pictures only have a tenuous relationship (at best) with what I'm writing about, but it's good to mix it up a little!
1 - Muscle Pain
What we experience as muscle soreness doesn't actually originate from the muscles themselves, but rather from the fascia (the epimysium, for any anatomy nerds out there) that surrounds the muscles. While this might seem like a small distinction, it could have huge implications for how we treat pain.
2 - Pain & Habits
Pain is our brain’s response to what it interprets as a dangerous situation. Similarly, the sensation you feel during a stretch probably doesn’t actually have anything to do with any mechanical properties of the muscle being stretched (the traditional view of what's happening during stretching). Rather, when a muscle has been habitually held in one position for a long time, (such as the hip flexors being in a shortened position while sitting), the brain starts to consider this to be the “correct” muscle length. It then takes a lot of convincing for the nervous system to let go and allow the joints to change position. Perhaps idiopathic pain is really the nervous system acting from a habituated state, rather than a symptom of a mechanical problem or injury.
3 - Pain & Injury
As crazy as it sounds, tissue damage does not always correlate to pain! It’s possible to have an injury that is pain-free, and on the other extreme there’s someone who experiences pain in a “phantom limb”, where there are no pain receptors involved.
4 - Pain & Movement
Proprioception is the ability to know where one’s body parts are in space. For instance, if I’m holding my arm behind me, then (assuming my proprioceptors and nervous system are healthy), I don’t need to look back to know where my arm is. Interestingly, proprioception inhibits nociception (the interpretation of a stimulus as pain). Also interestingly, there are lots of proprioceptors within ligaments, which are connective tissue structures found in and around joints. And in order for movement of a body part to happen, there must be movement at a joint, and therefore movement of the ligaments surrounding the joint.
Putting this in plain English, perhaps we NEED movement in order to not be in pain. Imagine someone who has back pain with no diagnosable cause, but they are advised to move the back as little as possible (perhaps until it “heals”), and maybe even become fearful to move. This leads to a gradual decrease in their use and movement of their back, which means that there is less stimulation of the proprioceptors in the back. It could then follow that the area becomes sensitized and starts interpreting signals as pain that would otherwise not be interpreted that way, and they enter a vicious cycle of less movement and more pain.
5 - Pain & the Brain
This last bit is actually from a class I took from fascia nerd and massage therapist Michael Hamm, but it ties in nicely to #4.
We have a HUGE number of nociceptors (the receptors that receive the input that can be interpreted as pain) all over our bodies. So why is it that we’re not in pain all over, all of the time? Because it’s possible for the nervous system to NOT interpret the signals from the nociceptors as pain. To put it another way, when a nociceptor is stimulated, pain is not the inevitable result.
So what determines whether our nervous systems will interpret a signal received by a nociceptor as pain? The short answer is, I don’t know! But what I gleaned from Mike’s lecture is that the brain, as well as the peripheral nervous system (the nerves outside of the brain and spinal cord) can get sensitized for various reasons and influence one another - it can go both directions. And the longer the pain has been going on, the more the brain gets involved.
And then, of course, our brains are influenced by things such as our culture and belief systems. I was fascinated to learn that different cultures have different words to describe pain. In the west, we tend to use very invasive words for pain, such as “stabbing”, “searing”, and “burning”. In contrast, other cultures talk about and experience pain differently. Is it possible that our words are actually creating our experience of pain?
Somebody Tell Me What This All Means!
As I said before, the short answer is, "I don't know". Sorry! It does make me wonder about what it means for our modern allopathic approach to pain treatment, though. We are currently experiencing an epidemic of undiagnosable pain, and have had little success treating it with pain "killers" and surgery.
Personally, the most useful things I've found for the chronic low back pain that used to drive me nuts are a combination of lifestyle changes such as ditching my furniture and making walking an almost-daily habit, movement modalities that have given me more awareness of how I use my body (RE primarily, as well as a bit of tai chi, qigong, and Feldenkrais), and mindfulness meditation. I still experience pain, of course (those nociceptors aren't there just for the heck of it), but my relationship and response to it has changed a lot. And the more it changes, the better able I am to accept, and perhaps even welcome the pain as a part of my body and brain, rather than something that I need to struggle against.