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On the subject of manual muscle work…There is more to it than meets the eye….

Following with our last few posts, here is an article that may seem verbose, but has interesting implications for practitioners who do manual muscle work with their clients. We would invite you to work your way through the entire article, a little at a time, to fully grasp it’s implications.

Plowing through the neurophysiology, here is a synopsis for you:

Tactile and muscle afferent (or sensory) information travels into the dorsal (or posterior) part of the spinal cord called the “dorsal horn”. This “dorsal horn” is divided into 4 layers; 2 superficial and 2 deep. The superficial layers get their info from the A delta and C fibers (cold, warm, light touch and pain) and the deeper layers get their info from the A alpha and A beta fibers (ie: joint, skin and muscle mechanoreceptors).

So what you may say.

The superficial layers are involved with pain and tissue damage modulation, both at the spinal cord level and from descending inhibition from the brain. The deeper layers are involved with apprising the central nervous system about information relating directly to movement (of the skin, joints and muscles).

Information in this deeper layer is much more specific that that entering the more superficial layers. This happens because of 3 reasons:

  1. there are more one to one connections of neurons (30% as opposed to 10%) with the information distributed to many pathways in the CNS, instead of just a dedicated few in the more superficial layers
  2. the connections in the deeper layers are largely unidirectional and 69% are inhibitory connections (ie they modulate output, rather than input)
  3. the connections in the deeper layers use both GABA and Glycine as neurotransmitters (Glycine is a more specific neurotransmitter).

Ok, this is getting long and complex, tell me something useful...

This supports that much of what we do when we do manual therapy on a patient or client is we stimulate inhibitory neurons or interneurons which can either (directly or indirectly)

  1. inhibit a muscle
  2. excite a muscle because we inhibited the inhibitory neuron or interneuron acting on it (you see, 2 negatives can be positive)

So, much of what we do is inhibit muscle function, even though the muscle may be testing stronger. Are we inhibiting the antagonist and thus strengthening the agonist? Are we removing the inhibition of the agonist by inhibiting the inhibitory action on it? Whichever it may be, keep in mind we are probably modulating inhibition, rather than creating excitation.

Semantics? Maybe…But we constantly talk about being specific for a fix, not just cover up the compensation. Is it easier to keep filling up the tire (facilitating) or patching the hole (inhibiting). It’s your call

The Gait Guys. Telling it like it is and shedding light on complex ideas, so you can be all you can be.

link: http://jn.physiology.org/content/99/3/1051

Take this simple test.   
 Want to be faster? Better incorporate some proprioceptive training into your plan. It is the 1 st  part of our mantra: Skill, Endurance, and Strength (in that order). Proprioceptive training appears to be more important that strength or endurance training from an  injury rehabilitation perspective  as well part of an  injury prevention  program 
  What is proprioception? It is body position awareness; ie: knowing what your limbs are doing without having to look at them. 
  Take this simple test:  
  Stand in a doorway with your shoes off. Keep your arms up at your sides so that you can brace yourself in case you start to fall. Lift your toes slightly so that only your foot tripod remains on the ground (ie the base of the big toe, the base of the little toe and the center of the heel.).  Are you able to balance without difficulty?  Good, all 3 systems (vision, vestibular and proprioceptive) are go. 
   Now close your eyes, taking away vision from the 3 systems that keep us upright in the gravitational plane.  Are you able to balance for 30 seconds?  If so, your vestibular and proprioceptive systems are intact. 
   Now open your eyes and look up at the ceiling. Provided you can balance without falling, now close your eyes. Extending your neck 60 degrees just took out the lateral semicircular canals of the vestibular system (see here for more info).  Are you still able to balance for 30 seconds?  If so, congrats; your proprioceptive system (the receptors in the joints, ligaments and muscles) is working great.  If not, looks like you have some work to do.  You can begin with exercises we use every day by clicking  here . 
  Proprioception should be the 1st part of any training and/or rehabilitation program. If you don’t have a good framework to hang the rest of your training on, then you are asking for trouble.  
  The Gait Guys. Your proprioceptive mentors.  We want you to succeed!

Take this simple test. 

Want to be faster? Better incorporate some proprioceptive training into your plan. It is the 1st part of our mantra: Skill, Endurance, and Strength (in that order). Proprioceptive training appears to be more important that strength or endurance training from an injury rehabilitation perspective as well part of an injury prevention program

 What is proprioception? It is body position awareness; ie: knowing what your limbs are doing without having to look at them.

Take this simple test:

  • Stand in a doorway with your shoes off. Keep your arms up at your sides so that you can brace yourself in case you start to fall. Lift your toes slightly so that only your foot tripod remains on the ground (ie the base of the big toe, the base of the little toe and the center of the heel.). Are you able to balance without difficulty? Good, all 3 systems (vision, vestibular and proprioceptive) are go.
  • Now close your eyes, taking away vision from the 3 systems that keep us upright in the gravitational plane. Are you able to balance for 30 seconds? If so, your vestibular and proprioceptive systems are intact.
  • Now open your eyes and look up at the ceiling. Provided you can balance without falling, now close your eyes. Extending your neck 60 degrees just took out the lateral semicircular canals of the vestibular system (see here for more info). Are you still able to balance for 30 seconds? If so, congrats; your proprioceptive system (the receptors in the joints, ligaments and muscles) is working great. If not, looks like you have some work to do. You can begin with exercises we use every day by clicking here.

Proprioception should be the 1st part of any training and/or rehabilitation program. If you don’t have a good framework to hang the rest of your training on, then you are asking for trouble. 

The Gait Guys. Your proprioceptive mentors. We want you to succeed!

Chronic ankle instability alters central organization of movement.

Haas CJ, Bishop MD, Doidge D, Wikstrom EA. Am J Sports Med 2010 Apr;38(4):829-34.

Epub 2010 Feb 5. Department of Applied Physiology and Kinesiology,University of Florida, Gainesville, Florida, USA.

 This is a recycle article from our “The Gait Guys” blog archive, June 2011. This article focuses on altered proprioception. Proprioception (or kinesthesis) is our ability to orient our body or a body part in space.  Poor proprioception can result in balance and coordination difficulties as well as being a risk factor for injury. Think about people with syphillis who lose all afferent information from a joint coming in through the dorsal root ganglia, this ultimately leads to a wide based ataxic gait (due to a loss of position and tactile sense) and joint destruction (due to loss of position sense and lack of pain perception). The same consequences can occur, albeit on a smaller scale, when we have diminished proprioception from a joint or its associated muscle spindles. As you read on, keep the thought in your mind that walking or running are both actually repeated attempts at finding a stable single leg stance, one after the other. Impairment of one single leg stance will affect the involved side locally as well as the contralateral side due to accelerated or abbreviated loading responses coming off of the affected side.  Arm swing will also be altered and require compensation.

Proprioception is subserved by both cutaneous receptors in the skin (pacinian coprpuscles, Ruffini endings, etc.), joint mechanoreceptors (types I,II,III and IV) and from muscle spindles (nuclear bag and nuclear chain fibers) . It is both conscious and unconscious and travels in two pathways in the nervous system. 

Conscious proprioception arises from the peripheral mechanoreceptors in the skin and joints and travels in the dorsal column system to ultimately end in the thalamus, where the information is relayed to the cortex and cerebellum.

Unconscious proprioception arises from joint mechanoreceptors and muscle spindles and travels in the spino-cerebellar pathways to end in the midline vermis and flocculonodular lobes of the cerebellum. This unconscious information is then relayed from the cerebellum to the red nucleus to the thalamus and back to the cortex, to get integrated with the conscious proprioceptive information and then central program generators (CPG’s). We have spoken about receptors more recently in the Gait Guys podcasts, #19 & 20 and CPG’s in our previous blog post this week if you care to delve more deeply into these topics.

Information from both systems (both separate and combined; the nervous system loves redundancy) is then sent down the spinal cord to effect some response in the periphery. As you can see, there is a constant feed back loop between the proprioceptors, the cerebellum and the cerebral cortex. This is what allow us to be balanced and coordinated in our movements and actions.

Chronic ankle instability is merely a more serious form of dysfunction on the continuum of ankle pathomechanics. It refers to subjects with both coronal and saggital plane stability problems due to altered proprioception. This results in a loss of fine motor coordination of the foot (ie foot intrinsics) and a recruitment of larger motor units about the joint (peroneus longus,  flexor and extensor digitorum longus, tibialis posterior and anterior, etc) . This is equivalent to writing a letter with a pencil taped to your wrist, rather than in your fingers. 

This study looked at plantar pressure changes (actually it measured the amount of deviation in forward/backward and side to side motions, which are corrective motions by the CNS due to a loss of fine motor control). As expected, they were greater in the group with ankle instability, particularly when they led with that foot (ie the impaired foot). Thus they lacked the skill necessary to perform the task and developed another movement or recruitment pattern to compensate.

This would be an excellent example of restoring function (ie skill)  for rehab, rather than just increasing strength. If fine motor control is not mastered 1st and you do not change the central pattern, you are carving a turnip with a chainsaw.

We are…. The Gait Guys