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View Full Version : Summary re "Do the elderly walk heavily on their heels?"



dmcfarlane
07-31-2007, 03:43 PM
Dear all,

This question provoked many interesting replies; here are the very best
ones.

Paul DeVita of East Carolina University said that "Older adults
generally have less ankle plantarflexor torque and power near the end of
each stance phase. So, now I conjecture that this reduced ankle output
results in less forefoot pressure onto the ground and less of an
indentation into the ground by the forefoot. Thus, relatively speaking,
older adults would have more heel indentation and less forefoot
indentation."

Noel Lythgo (University of Melbourne) at the Royal Talbot Rehabilitation
Centre said that some work "has shown a significantly lower plantar
flexion power "burst" in terminal stance phase of gait for elderly
subjects (see attached paper). Other work suggests age causes a
re-distribution of joint power production where more power is produced
at the knee and hip with reduced power production at the ankle. Both of
these factors could lead to more time spent on the heel. Essentially an
aging gait pattern involves a lifting and pulling of the leg by hip and
knee musculature as opposed to the leg being driven by the ankle plantar
flexors."

Noel also provided this reference;
C.McGibbon, (2003), "Toward a better understanding of gait changes with
age and disablement: neuromuscular adaptation", Exerc Sport Sci Rev.
2003 Apr;31(2):102-8.

Ton van den Bogert said that "There is actually a scientific basis for
this, and it is related to strength, not speed.

During the push-off phase, there is a powerful contraction of the
plantarflexors which pushes the toes down to the ground. Older people
have less muscle strengh, and the imprint of the toes will probably not
be as deep. I did quick lit search and found a few publications showing
lower plantarflexor moments with increasing age."

So it looks as if old Dersu was onto something!

Does anyone know whether this heel-heavy tendency reduces stability in
any circumstances?

Regards,

David McFarlane MAppSc (Ergonomics)
Ergonomist, WorkCover NSW

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