Dear netters:

In response to the questions proposed by Mark Swanepoel with respect to
which parts of the gait cycle are slowed in the elderly and the changes
in force patterns in stance phase, I am happy to provide more data about
the walking patterns of elderly for further comments.

With the definition that young group aged 13-44 and old group aged
45-74, several t-tests were performed to test the differences between
old and young group of each gender/ racial catalogue ( Caucasian Women,
young (n=18, mean age 29),old (n=23, mean age 55); Caucasian men, young
(n=32, mean age 31),old (n=18, mean age 60); Asian women, young (n=50,
mean age 30),old (n=31, mean age 57); Asian men, young(n=30, mean age
30),old(n=17, mean age 59)).


(1) Changes in stance duration / double stance duration with age:
Old Asian (women and men) walked with significantly longer
stance phases than young Asian. Further to the details, Old Asian women
increased double stance phase significantly, but Asian men did not
increase those significantly.
No significant differences in event proportion of gait cycle
between old Caucasian and young Caucasian were found.

(2) Changes in maximal vertical force with age
Significant decrease in maximal vertical force (in stance
phase) with age were found in Caucasian men and Asian women. In
contrast, bigger maximal vertical force was found in old Caucasian women
although without reaching significance level

(3) the differences between heel-strike force and toe-off force:
The differences were defined as the force amplitude of first
major peak (heel-strike force) subtracted by that of the second major
peak ( push-off). It was positive when heel-strike force is bigger in
this study.
Asian group appeared to have more even force distribution than
Caucasian but without differences between young groups and old groups
(-2.7 - 2.9 %BW). Young Caucasian men demonstrated a significantly
bigger heel-strike force (9.5%BW), whereas the force patterns become
more even in old Caucasian men (3.2%BW) (p