Stretching part 2

So, how can we utilize this reflex? 

How about to activate a weak or lengthened muscle?

Did you notice the other neuron in the picture? There is an axon collateral coming off the Ia afferent that goes to an inhibitory interneuron, which, in turn, inhibits the antagonist of what you just stretched or activated. So if you acitvate one muscle, you inhibit its antagonist, provided there are not too many other things acting on that inhibitory interneuron that may be inhibiting its activity. Yes, you can inhibit something that inhibits, which means you would essentially be exciting it. This is probably one of the many mechanisms that explain spasticity/hypertonicity

How can we use this? How about to inhibit a hypertonic muscle?
Lets take a common example: You have hypertonic hip flexors. You are reciprocally inhibiting your glute max. You stretch the hypertonic hip flexors, they become more hypertonic (but it feels so good, doesn’t it?) and subsequently inhibit the glute max more. Hmm. Not the clinical result you were hoping for?
How about this: you apply slow stretch to the glutes (ie “reverse stretch”) and apply pressure to the perimeter, both of which activate the spindle and make the glutes contract more. This causes the reciprocal inhibition of the hip flexors. Cool, eh? Now lightly contract the glutes while you are applying a slow stretch to them; even MORE slow stretch; even MORE activation. Double cool, eh?

Don’t believe me, try this on yourself, your clients, patients, willing family members and pets.

Image credit: https://commons.wikimedia.org/wiki/File:The_extensor_digitorum_reflex.jpg

Stretching part 1

Stretching secrets you need to know

OK, maybe they aren’t secrets, but these are some ‘shortcuts” you should know. 

We know from studies out there that static stretching can lengthen muscle (actually add sarcomeres), but you need to do it 30 minutes per day per muscle group. How about something a little faster doc?

How about taking advantage of the stretch reflex and reciprocal inhibition; or the “reverse stretch”

Reciprocal inhibition is a topic we have spoken about before on our blog, social media and our PODcasts. 1st described in1923 by Sherrington, this diagram sums it up nicely. Note the direct connection from the spindle to the alpha motor neuron, which is via a Ia afferent fiber. When the spindle is stretched, and the pathway is intact, the muscle will contract. This its a straight forward stretch or inverse myotatic reflex. 

Remember, ANY kind of stretch or anything that changes the length of the spindle will effect it. So what happens when you do a nice, long, slow stretch? You ACTIVATE the spindle, which activates the alpha motor neuron. If you stretch long enough, you may fatigue the reflex. So why do we give folks long, slow stretches to perform? Good question! Certainly not to “relax” the muscle!

So, how can we utilize this reflex? Read our next post tomorrow!



Image credit: https://commons.wikimedia.org/wiki/File:The_extensor_digitorum_reflex.jpg

Making your stretching more effective. 

While I was making linguine and clam sauce for my family, one of my favorite foods that I haven’t had in quite some time( and listening to Dream Theater of course) I was thinking about this post.  Then I remembered about voice recognition on my iMac.  Talk about multitasking!

What do you agree that stretching is good or not, you or your client still may decide to do so possibly because of the “feel good” component. Make sure to see this post here on “feel good”  part from a few weeks ago. 

If you do decide to stretch, make sure you take advantage of you or your clients neurology.  There are many ways to do this. One way we will discuss today is taking advantage of what we call myotatic reflex.

The myotatic reflex is a simple reflex arc. The reflex begins at the receptor in the muscle (blue neuron above) : the muscle spindles (nuclear bag or nuclear chain fibers). This sensory (afferent) information then travels up the peripheral nerve to the dorsal horn of the spinal cord where it enters and synapses in the ventral horn on an alpha motor neuron.  The motor neuron (efferent) leaves the ventral horn and travels back down the peripheral nerve to the contractile portion of the myfibrils (muscle fiber) from which the the sensory (afferent) signal came (red neuron above).  This causes the muscle to contract. Think of a simple reflex when somebody taps a reflex hammer on your tendon. This causes the muscle to contract and your limb moves.

Nuclear bag and nuclear chain fibers detect length or stretch in a the muscle whereas Golgi Tendon organs tension. We have discussed this in other posts here.   With this in mind, slow stretch of a muscle causes it to contract more, through the muscle spindle mechanism.

Another reflex that we should be familiar with is called reciprocal inhibition. It states simply that when one muscle (the agonist) contracts it’s antagonist is inhibited (green neuron above).  You can find more on reciprocal inhibition here.

Take advantage of both of these reflexes?   Try this:

• do a calf stretch like this: put your foot in dorsiflexion, foot resting on the side of the doorframe.
• Keep your leg straight.
• Grab the the door frame with your arms and slowly draw your stomach toward the door frame. 
• Feel the stretch in your calf; this is a slow stretch. Can you feel the increased tension in your calf? You could fatigue this reflex if you stretched long enough. If you did, then the muscle would be difficult to activate. This is one of the reasons stretching seems to inhibit performance. 
• Now for an added stretch, dorsiflex your toes and try to bring your foot upward.  Did you notice how you can get more stretch your calf and increased length? This is reciprocal inhibition at work!

There you have it, one neurological tool of many to give you increased length.The next time you are statically stretching, take  advantage of these reflexes to make it more effective.

 The Gait Guys. Teaching you more  about anatomy, physiology, and neurology with each and every post. 

image from :www.positivehealth.com