Article

Older adults walk more slowly, take shorter steps, and spend more time with both
legs on the ground compared to young adults. Although many studies have
investigated the effects of aging on the kinematics and kinetics of gait, little
is known about the corresponding changes in muscle function. The aim of this
study was to describe and compare the actions of the lower-limb muscles in
accelerating the body's center of mass (COM) in healthy young and older adults.
Three-dimensional gait analysis and subject-specific musculoskeletal modeling
were used to calculate lower-limb muscle forces and muscle contributions to COM
accelerations when both groups walked at the same speed. The orientations of all
body segments during walking, except that of the pelvis, were invariant to age
when these quantities were expressed in a global reference frame. The older
subjects tilted their pelves more anteriorly during the stance phase. The mean
contributions of the gluteus maximus, gluteus medius, vasti, gastrocnemius and
soleus to the vertical, fore-aft and mediolateral COM accelerations (support,
progression and balance, respectively) were similar in the two groups. However,
the gluteus medius contributed significantly less to support (p<0.05) while the
gluteus maximus and contralateral erector spinae contributed significantly more
to balance (p<0.05) during early stance in the older subjects. These results
provide insight into the functional roles of the individual leg muscles during
gait in older adults, and highlight the importance of the hip and back muscles in
controlling mediolateral balance.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

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