September 9, 2021
Pondering Postural Control Update: Muscle Tone
My apologies again for the long radio silence. I hope you are all staying safe and taking care of yourselves and each other.
Last summer I offered a live, online course called Foundation for Function. It was a deep dive into postural control and I was honoured by the group of therapists who took that leap of faith with me and completed a 16-session intensive examination of the systems involved in postural control. For those of you who read my original Pondering Postural Control series on this blog, the model I now use (see the graphic below) is quite different from the one I started with.
With new research and reading comes updated clinical reasoning. The first additional component of this model is Muscle Tone. As therapists, we perceive muscle tone as the feel of the muscle under our hands but in reality we are feeling many different layers and it can be difficult to articulate them. I break it down this way.
Neurologically we can consider the contributions of:
- The vestibulospinal tract serving the anti-gravity extensors of the trunk and legs.
- The muscle spindles of the proprioceptive system communicate with gamma and alpha motor neurons.
- The corticospinal tract as damage can cause spasticity.
- The reticulospinal tract as it connects our arousal to our muscles.
Mechanically we can consider the contributions of:
- Inherent viscoelastic property of the muscle.
And finally in Dynamic Holding we can consider:
- The recruitment pattern a client develops to compensate for decreased postural control.
Muscle tone can impact many of the other components of postural control such as musculoskeletal, emotional regulation, and anticipatory mechanisms. As an example you can check out my short discussion of some connections between muscle tone and emotion here.
This is the nature of dynamic systems theory – #itsallconnected.