But it doesn’t make sense – How could the pain you’re feeling NOT be due to the pain? Well… it’s because you can’t feel movement.
I’d always learned and read this in school, but sometimes a “refresher” is nice. I recently read a journal article that did that for me (Changes in Aβ non-nociceptive primary sensory neurons in a rat model of osteoarthritis pain [Molecular Pain 2010, 6:37]). Unfortunately, journal articles can be a pain to read. You need to look through the authors opinions, crappy statistical analysis, misreporting, etc. Anyway, that’s not what today’s post is about…
So what was the article about?
- The authors had mice that were either “normal” (not surgically injured) and those who were given osteoarthritis (surgical removal of medial meniscus and partial removal of the ACL in the knee)
- Time was passed and osteoarthritis developed in those rats with the surgical injuries (poor little guys)
- The authors then tested the rats neural pathways for nociception (pain) and mechanoreception (proprioception – range of motion/body sense/knowing where you are in space)
So what did they find? (all results are in comparison to the healthy, happy rats)
- The injured rats were much more quick to react to stimuli that would not normally perceived as pain (they were very sensitive to stimuli that could eventually be painful – think poking the back of your hand lightly with a toothpick versus pushing it into your skin)
- The resting potential of nerves responsible for the perception of pain were closer to depolarizing than control rats (this means less stimuli is required for these rats to experience pain)
- Conversely, the mechanoreceptors were further from depolarizing in the injured rats (this means they weren’t just not moving as much, their movement wasn’t being recognized by the brain as much
Why does this matter to you?
Like I’ve said before, movement and pain are competitive inhibitors, meaning they cancel each other out. This is often responsible for the good feeling you have after exercising (outside of the hormonal response) and chiropractic. Chiropractic being the donor of full, accessible, pain-inhibiting range of motion signals to your brain.
But those mice have arthritis and I don’t!
Maybe. Not to be a debbie downer, but most people have knee/elbow/shoulder/wrist/low back pain that isn’t really pain per se, but is inconvenient or annoying. That’s the very early stages of osteoarthritis, unless the reason you’re having that recurring problem (posture, movement patterns, etc.) is remedied. Besides, wouldn’t you want your brain and joints to benefit from a full range of motion?
All the best folks!