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Brian Glaister
07-22-2004, 05:07 AM
Thanks to all who responded to my request about skeletal transients. Below is
a summary of the responses I received. It appears that there is quite a
controversy as to which method should be used.

Accelerometers:

Many of the respondees advocated support for the use of accelerometers to
measure skeletal transients. The controversy lies in how the data is analyzed.

Much research has been performed in this area by analyzing the peak axial
accelerations at heel strike [1-4]. However, no one responding to my request
advocated this method.

A second method using a spectral analysis to include both peak accelerations
and frequencies has been used [5-9]. This method received some support from
members of this listserv due to a belief that both the peak accelerations and
frequencies contribute to overuse injury. It is also believed that by using
this method, less trials are needed to get representative data.

A third method reported in the literature and advocated by members of this
listserve is the use of a loading rate [10]. This method divides the peak
acceleration amplitude over the acceleration time under the belief that the
more rapid the loading, the greater the risk of injury.

Force Plates:

A few responders advocated the use of force plates [11]. This method also
received a few responses advocating against it for the belief that the force
plate method measures full body accelerations, not those present in the tibia.
There is also a paper published that states that the geometry of impact can
affect force plate initial loading values, but not accelerometer initial
loading values [12] though this was disputed by one responder claiming a
conflict of interest with the authors.

What does this all mean? I think it means we all have a lot of thinking to do.
There certainly is a lot of disagreement in the literature and on this
listserv. Personally, in terms of evaluating prosthetic feet in my work, I
think I will try an array of these techniques and attempt to correlate the
results with patient perception of shock to determine the most appropriate
method for what Iím doing. I still welcome comments and references I may have
missed.

Thanks,
Brian Glaister
The Biodesign Institute at Arizona State University



[1] L. H. Light, G. E. McLellan, and L. Klenerman, "Skeletal transients on
heel strike in normal walking with different footwear," J Biomech, vol. 13,
pp. 477-80, 1980.
[2] B. Rooser, R. Ekbladh, and L. Lidgren, "The shock-absorbing effect of
soles and insoles," Int Orthop, vol. 12, pp. 335-8, 1988.
[3] J. L. van Leeuwen, L. A. Speth, and H. A. Daanen, "Shock absorption of
below-knee prostheses: a comparison between the SACH and the Multiflex foot,"
J Biomech, vol. 23, pp. 441-6, 1990.
[4] H. W. Van Jaarsveld, H. J. Grootenboer, and J. De
Vries, "Accelerations due to impact at heel strike using below-knee
prosthesis," Prosthet Orthot Int, vol. 14, pp. 63-6, 1990.
[5] G. R. Johnson, "The use of spectral analysis to assess the performance
of shock absorbing footwear," Eng Med, vol. 15, pp. 117-22, 1986.
[6] G. R. Johnson, "The effectiveness of shock-absorbing insoles during
normal walking," Prosthet Orthot Int, vol. 12, pp. 91-5, 1988.
[7] G. R. Johnson, "Measurement of shock acceleration during walking and
running using the Shock Meter," Clinical Biomechanics, vol. 5, pp. 47-50, 1990.
[8] J. F. Lehmann, R. Price, S. Boswell-Bessette, A. Dralle, K. Questad,
and B. J. deLateur, "Comprehensive analysis of energy storing prosthetic feet:
Flex Foot and Seattle Foot Versus Standard SACH foot," Arch Phys Med Rehabil,
vol. 74, pp. 1225-31, 1993.
[9] J. F. Lehmann, R. Price, S. Boswell-Bessette, A. Dralle, and K.
Questad, "Comprehensive analysis of dynamic elastic response feet: Seattle
Ankle/Lite Foot versus SACH foot," Arch Phys Med Rehabil, vol. 74, pp. 853-61,
1993.
[10] M. Ogon, A. R. Aleksiev, M. H. Pope, C. Wimmer, and C. L.
Saltzman, "Does arch height affect impact loading at the lower back level in
running?," Foot Ankle Int, vol. 20, pp. 263-6, 1999.
[11] S. A. Gard and R. J. Konz, "The effect of a shock-absorbing pylon on
the gait of persons with unilateral transtibial amputation," J Rehabil Res
Dev, vol. 40, pp. 109-24, 2003.
[12] M. A. Lafortune and E. M. Hennig, "Cushioning properties of footwear
during walking: accelerometer and force platform measurements," Clinical
Biomechanics, vol. 7, pp. 181-184, 1992.

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