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View Full Version : Summary: When lifting is it better to look straight forwards ortuck your chin in?



dmcfarlane
07-19-2006, 09:44 AM
It seems that everybody agrees that it is advisable to keep one's chin
up when lifting low-lying loads. Here are the responses.
Rod Whiteley said that Aspden's work describing the lumbar spine as an
arch explains "why weightlifters maintain a lumbar lordosis" and added
that the instruction "Look upwards" will aid this synergistic movement.
Aspden (1988) developed a model which assumes that the spine functions
in a similar way to an arch; this model shows that spinal stresses are
not as great as those predicted by the traditional cantilever model and
that the stress is strongly dependent on posture. he stressed that a
knowledge of the postures in which the spine is least stressed while
performing a particular task are of considerable importance. Aspden
subsequently analysed three postures and associated loads described in
the literature (1989).
John Casler (of Tri-Vector 3-D Force Systems) referred to the "torso
stabilization mechanisms" and said that even looking forward is
inadequate to elicit the cascading reflex action of the spinal, torso
and kinetic chain extensors. He said that it is very important for back
patients to keep their chins up (literally). He advised that;
* one should "NEVER" look down lifting under loaded conditions
* looking "up" causes the inital extension reflex in the extenders
of the cervical spine which then causes a cascading extension reflex
through the rest of the Kinetic (lifting) Chain.
Dr Hamid Rassoulian of Southampton General Hospital speculated that;
"the spinal cord and all of the nerves (in particular) the major nerves
such as the sciatic nerve can be thought of as a rope that is subject to
a tensile stress when we bend down for example. Whilst the head pivots
over the neck if it is moved forward it can result in additional stress
of the spinal cord (which would already be under tension due to the
bending posture adopted). This can be through further stretching of the
cord itself as well as generating more of a curvature at the cervical
segment of the spine thereby increasing the tension on the cord."
On this basis he suggested that looking up might reduce the tension or
at least avoid any additional burden on the cord and the nerves.
Philip Newell (of Rehabilitation and Education Personal Fitness
Professionals, Fort Wayne) agreed with Dr Rassoulian's concept of
tension on the spinal cord. He argued that this is also necessary to
protect the musculoskeletal anatomy of the lower back because the
muscles of the posterior chain, (erector spinae, gluteal muscles and
hamstrings) will probably achieve greater contraction if all of the
erectors along the spine are contracted. He said that this would not be
possible if the neck was held in flexion.
Robert Kell (of the University of Regina) said that in his experience it
is usual for successful lifters to look straight ahead or even slightly
upwards.
Susan Chinworth of Elon Unversity said that her clinical experience
suggests that instructing clients to look up or look ahead before they
start a lift from a low surface promotes a better spinal posture and
spinal stabilization during the lift.
Benjamin Winkel agreed that a forward-looking approach should lead to a
better posture.
On the basis of his experiences from many years of weight lifting David
Smith strongly recommended keeping the chin up when lifting from the
squat position. He pointed out that;
* looking upwards gives the feeling that this is direction of the
lift
* extension of the shoulder girdle is impossible with the head
down and
* it is difficult to breath properly with your chin on your chest.

Keeping the chin against the chest certainly sounds like a way "forcing
the variable" (if anyone wants to test that hypothesis) but it sounds as
if it might be too risky to trial. However, given that most of the
responses were based on experience, informal observations and
interpretations of theory this area might be a fruitful area for further
formal research.
Regards,
David McFarlane
Ergonomist, WorkCover Authority
New South Wales, Australia
References
Aspden, R. M. (1988). "A new mathematical model of the spine and its
relationship to spinal loading in the workplace." Appl Ergon 19(4):
319-23.
Aspden, R. M. (1989). "The spine as an arch. A new mathematical model."
Spine 14(3): 266-74.
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