Before we talk about this next one, we need to give you a little background (neurologically speaking).
Take a look at the picture above and note the posturing of the baby in the 2 positions. These neurological reflexes (or postures) are called symmetrical tonic neck reflexes or responses (STNR’s for short) and were described in animals and men by Magnus and de Kleyn in 1912 (1). This work was later studied and reported by by Arthur Simons in 1916 (2) and later by Francis Walshe in 1923 (3). These were later made popular by Berta and Karl Bobath in the 70’s (who studied Walshes work), whom they are often attributed to (4).
You next question is “Do these persist into healthy adulthood”? and the answer is a resounding YES (5).
Take a look at the picture above again and note the following:
When the neck is flexed, the fore limbs flex (and the muscles facilitating that, bicep, brachialis, anterior deltoid are contracting) and the hind limbs are extending (relatively), with the glutes maximus, quadriceps, foot dorsiflexors contracting.
Note that when the head is extended, the forelimbs are extended and the hind limbs flexed. Think about the muscles involved. Upper extremity tricep, anconeus, posterior deltoid, lower back extensors, hamstrings and foot plantar flexors facilitated.
The reflex is based on the mechanoreceptors in the neck articulations and muscles and are frequently used by us and many others in the rehabilitation field. Generally speaking, looking up facilitates things which make you extend above T12, and flex below T12. Looking down facilitates flexion above T12 and extension below.
We would encourage you at this point to “assume” these positions and feel the muscles which are active and at rest.
So, how can we take advantage of these while stretching?
Think about your head position:
If you are standing up and hinging at the hips to stretch your hamstrings (notice we did not say “bent at the waist”; there is a BIG difference in shear forces applied to your lumbar spine) you would probably want your neck bent forward, as this would fire your quads which would in turn ALSO inhibit your hamstrings, in addition to the STNR inhibiting the hamstring.
If you were in a hip flexor stretch position, you would want you head up, looking at the ceiling to take advantage of the reflex.
We are confident you can think of many more applications of this reflex and trust that you will, as it can apply to both upper and lower extremity stretches. Just remember that this reflex is symmetrical and will affect BOTH sides. Of course, there are reflexes that only effect things unilaterally, but that is the subject of another post.
The Gait Guys. Helping make you better at what you do for yourself and others and assisting you on using the neurology that God gave you.
Simons A (1923) Kopfhaltung and Muskeltonus. Ges.Z. Neurol.Psychiatr. 80: 499-549.
Walshe FMR (1923) On certain or postural reflexes in hemiplegia, with special reference to the so-called “associated movements.” Brain 46: 1-37.
Janet M. Howle . Symmetrical Tonic Neck Reflex in Neuro-developmental Treatment Approach: Theoretical Foundations and Principles of Clinical Practice. NeuroDevelopmental Treatment, 2002 p 341 ISBN 0972461507, 9780972461504