Alternating
the spine between flexion and extension in four point kneeling has been around
for a long time. It is very popular and has found its way into many hospital
and clinic based home exercise sheets in different formats.
Biomechanics
McGill
2001 has recommended a variation of this exercise. He feels this exercise facilitates motion
for the spine with very low loading, reduces viscous stresses for subsequent
exercise, and “flosses” the nerve roots through the foremina at each spine
joint. It has been referred to as "milking the spine".
Yoga
These
movements are very similar to the popular "Cat - Cow" poses.
Behavioral Rehab
This
exercise is used to gradually increase spinal range of motion for people who
have fear of large or end range spinal movements.
Specific Movement Pattern
Control Exercises
A
common specific movement pattern control exercise is to independently perform a
lumbo-sacral anterior and posterior pelvic tilt to mid range while maintaining
the hips, thoracic (and thoraco-lumbar) and cervical spine in a general neutral
(mid-range position). This movement aims to bias the global stability pelvic
tilt muscles for anterior pelvic tilt (lumbar multifidus, iliacus, psoas major
from above) and posterior pelvic tilt global stability muscles (gluteus
maximus, internal and external oblique psoas major from below) over the global
mobility muscles (anterior tilt: iliocostalis, longissimus; posterior tilt:
rectus abdominis, hamstrings) (Gibbons 2011).
During
four point kneeling exercises it is observed that some people cannot perform a
specific neutral spine, while others seem to do it very poorly with quite a bit
of paraspinal muscle tone. Some even seem to move their cervical spine during
this or move their hips into flexion or extension. These people undoubtedly
have a Symmetrical Tonic Neck Reflex (STNR) (Figure 1a and 1b). This is one of
over seventy confirmed primitive reflexes (PR). The underlying reason for their
poor movement pattern will be related to the presence of PR.
PR are
brain stem-mediated, complex automatic movement patterns that commence in
utero. If PR persist beyond their
average lifespan they may begin to interfere with proper CNS development,
normal movement and could indicate neurological impairment. They present in
conditions such as learning difficulties or movement disorders in children and
adults. PR can also reappear due to
altered sensory input into the CNS (musculoskeletal injury) or altered
processing (i.e. concussion). The
presence of PR will influence motor control and can interfere with normal
rehabilitation.
Suggested benefits of the
rehabilitation of the STNR (in addition to the above)
Spinal mobilization
This
extension phase of the exercise will mobilize the thoracic spine into extension
particularly when expiration is used. The flexion phase will mobilize the lower
lumbar spine into flexion particularly when inspiration is used. These movement patterns are commonly altered
in mechanical pain presentations and can aid in improving movement patterns for
specific movement pattern control exercises.
Direction Preference
In
addition to the above, if a patient has symptoms in one direction, this is a
safe movement pattern to move the spine into end range positions to get temporary
relief.
Neural Mobilization
The
straight leg raise and the slump test frequently improve after the treatment of
the STNR. This may be due to the explanations given by McGill and the above as
well as non specific reasons.
General Coordination
The
STNR is more specific than the popular yoga pose and alternating flexion -
extension described above. If opposite or incorrect patterns are practiced,
flare ups have been documented. Although they require much less cognitive and
sensory motor input than specific movement pattern control exercises, there is
a small element of coordination involved. This can be a stepping stone onto
more challenging coordination exercises.
Tone
The
flexion ad extension patterns alter tone in the relative muscular patterns they
are present in. This change is immediate in most people.
Midline Rehab
Despite
this exercise being "symmetrical", it is quite relevant for our
bodies midline and for body image.
During delivery of an
infant, there are six movements of the baby enable it to adapt to the maternal
pelvis: descent, flexion, internal rotation, extension, external rotation, and
expulsion (Note: some authors refer to seven movements and include
"engagement" prior to "descent") (Hacker et al 2009). The
STNR is
believed to be used by infants to aid in going through the birth canal and also
be a bridge reflex for other developmental movements. Hence, there are other
movements beyond those depicted in figure 1a and b.
The
variations of this exercise have stood the test of time and as noted above,
have many benefits. We should put the exercise in its proper place and
appreciate it is best used as the STNR.
Figure 1a & 1b: Symmetrical Tonic Neck Reflex extension and
flexion phases
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1a (top): STNR extension phase and 1b flexion phase
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Sean GT Gibbons BSc (Hons) PT, MSc Ergonomics, PhD (c), MCPA
References
Gibbons SGT 2011 Problem solving in specific
motor control exercise rehabilitation. Neuromuscular Rehabilitation Review.
1: 7-12
Gilfoyle EM Grady AP Moore JC 1990 Children
Adapt. A Theory of Sensoirmotor-Sensory Development. 2nd Ed. SLACK
Incorporated, Thorofare
Hacker NF, Gambone
JC, Hobel CJ 2009 Essentials of Obstetrics and Gynecology. 5th Ed. Saunders,
Philadelphia
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