PNF Principles- Tactile Input Cont'd
So in the last post we started talking about tactile input which is the first principle we need to consider when discussing how to deliver proper proprioceptive input.
Remember under tactile input we have to consider
1a. Patient position (which was the topic of the last post)
1b. Manual contact.
1b. Manual Contact:
Maggie Knott use to say “What you touch is what you get.” Where you put your hands can greatly affect the motor response with something as simple as a manual muscle test.
Try this: Test someone’s shoulder flexion strength. Use one hand to resist the distal humerus while the non-resisting hand is just resting on their back/trunk extensors: Figure A.
Next, test their strength again while resting your non-resisting hand on their pec major or anywhere on the front side of their trunk (trunk flexors) Figure B.
What hand position gave you a stronger shoulder flexion response?
When I do it I feel stronger shoulder flexion with the hand position in Figure A
why is the response so different?
Well, when we cue our clients (with a relatively intact CNS) both the conscious and subconscious motor control centers of the CNS are at play to produce the desired motor response.
How we affect each system matters. We can learn a lot about this by learning a little about about Dr. Kabat and Maggie Knott’s lessons they took away from co-treating children with post-polio and other CNS disorders. What Dr. Kabat and Maggie Knott picked up on were movement patterns that were often neurologically linked together or, “hard wired,” in pathological situations (abnormal tonal synergies) that made function very difficult for these children.
Being able to identify these abnormal tonal patterns in the limbs, helped Maggie and Dr. Kabat come up with movement patterns and techniques that reversed these dysfunctional tonal patterns which helped these children functionally move out of the abnormal tone. Dr. Kabat also used the functional anatomy of how the synergistic muscles of the limbs spiraled back into the torso to come up with these patterns to reduce abnormal neurological tone.
To go back to the shoulder flexion muscle testing example notice how the referee in Figure C shows how trunk extension is typically linked with both shoulder flexion and wrist extension in non-pathological situations.
In PNF lingo it’s called bilateral upper extremity D2 flexion or flex/abduction/External rotation.
Figure D shows how trunk flexion is linked to shoulder extension. Or in other words, using shoulder extension helps us facilitate trunk flexor activity. The picture below shows a bilateral upper extremity D2 extension or extension/adduction/internal rotation.
Again going back to the shoulder flexion test example from earlier, Think of it like this:
Placing one hand on the trunk flexors, stimulates the “subconscious trunk flexor motor centers” which is neurologically linked to shoulder extension.
You’re stimulating the trunk flexors while you’re asking the “conscious shoulder flexor centers” to give you a shoulder flexion motor output. Remember the system wants to use trunk extension to assist in shoulder flexion (picture of the referee), basically the brain gets confused as to what you want it to do.
Giving a tactile input to trunk flexors via manual contact is very contradicting input for the sensorimotor system if the motoric goal is a strong shoulder flexion response.
Remember what you touch matters, and “what you touch is what you get” so we have to be mindful of the manual goal and know where to place our hands accordingly for both neurological and orthopedic reasons.
If you have taken courses in Orthopedic Manual Therapy and/or Neurological Manual Therapy such as Functional Range Release (FR), Neuro Developmental Treatment (NDT), Dynamic Neuromuscular Stabilization (DNS), and PNF, the importance of a “soft/gentle” manual contact should be very familiar to you.
The concept of a gentle touch is extremely important and demands that we as the therapists remain focused in the present moment with our patients rather than obsessing over what happened before and what may happen after.
Next I will discuss The PNF Basic Principle of: Therapist Position