STRETCHING THE HAMSTRING MUSCLE vs SCIATIC NERVE GLIDES


Sometimes a patient will come in with tightness or pain behind their thigh.  Through evaluation, the therapist may conclude that their symptoms may be nerve related and decide to give exercises that do not involve long sustained stretches.  Instead the activity will involve a repeated nerve glide.  The reason being that long sustained stretches and repeated range of motion exercises will affect tissues differently.


Stretching a muscle with a long sustained stretch is optimal to provide "elongation of tissue beyond it's intrinsic extensibility resulting from a constant load over time" (1) 

Stretching a nerve, if injured, can actually irritate the nerve and possibly exacerbate symptoms. (2)


When gliding a nerve, you are trying to "separate the nerve from the surrounding structures by sliding the nerve via joint movements that lengthen the nerve bed." (3)


Gliding, or "flossing", is an exercise to improve the extensibility of the nerve "by mildly stretching and releasing it over and over". (4)


​​ANATOMY AND TESTING







 
















​​​NERVE GLIDES


Based on the severity of your symptoms and positional tolerance, your therapist can instruct you on different positions and methods to perform a nerve glide.  The following two methods can be done easily in sitting.

Method A
1. Patient starts by bending the ankle of the treating leg so that the toes are pointing upward. 
2. The patient lifts the leg by straightening the knee joint.
3. Stop when symptoms (pain, numbness, tension, etc) are felt.
4. Don’t hold the leg for too long (no more than 3 seconds) in the stretched

position then bring the leg down.

5. Repeat 

Method B
1. The patient starts with the ankle relaxed
2. Raise the leg up until symptoms are reported
3. Bend ankle as you point toes up and down repeatedly

If symptoms improve, the patient can stretch the knee farther into extension.  You won’t really know how helpful an exercise is until you’ve tried it extensively.  Especially with nerve gliding, increased repetition (about 20-30 times every hour) will help loosen the tissue and stimulate blood flow to help heal the injured areas.  ​


CONCLUSION


Understanding the source of your symptoms will allow the therapist to provide a better treatment plan.  Important factors such as discovering the cause of the pain (if the pinched nerve is coming from the lower back or other musculoskeletal structure) as well as changes in activity function (i.e improved posture or biomechanics) will help to prevent further exacerbation of your symptoms and promote optimal healing of the tissues. 




-- Duffy Chan, PT


References

1. http://www.mecaback.com/creep/  

2. http://physioworks.com.au/treatments-1/neurodynamics-neuro-mobilisation

3. http://www.thestudentphysicaltherapist.com/home/how-to-treat-neural-tension

4. http://www.maximumtrainingsolutions.com/Lower-Extremity-Nerve-Glide.html

5. http://www.spine-health.com/conditions/spine-anatomy/sciatic-nerve-anatomy


The hamstring muscle crosses two joints starting from the back of the hip and into the sides of the knee joint. When performing a straight leg raise, the subject is lying on his or her back.  The leg is lifted with the knee in full extension.  Tension should be limited to the back of the hip and through the back of the knee.  You may have some referred symptoms that project into the calf.

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The sciatic nerve extends out from the spinal cord and into the leg with individual nerves branching out all the way down to the toes.  It is part of a continuous pathway that connects all the way into the brain via the spinal cord.  (5) Differentiating the nerve from hamstring muscle can be achieved either by putting the spine on tension (have the person lift the head) or by putting the individual nerve branches on tension (bending the ankle backward)