Article

Bilateral transtibial amputee (BTA) gait has been investigated less and is not as
well understood compared to that of their unilateral counterparts. Relative to
able-bodied individuals, BTAs walk with reduced self-selected speeds, increased
step width, hip-hiking, and greater metabolic cost. The clinically observed upper
body motions of these individuals have not been quantified, but appear
substantially different from able-bodied ambulators and may impact upright
balance. Therefore, the objective of this study was to characterize the upper
extremity kinematics of BTAs during steady-state walking. We measured
medial-lateral ground reaction forces, step width and extrapolated center-of-mass
(XCoM) trajectory, and observed effects of walking speed and increased prosthetic
ankle range-of-motion (ROM) on these parameters. Significantly, BTAs display
greater lateral trunk flexion ROM and shoulder abduction than able-bodied
individuals when walking at similar speeds, and the inclusion of prosthetic
adaptors for increasing passive ankle ROM slightly reduced step width. Overall,
exaggerated lateral trunk flexion ROM was invariant with step width. Results
suggest that lateral trunk motion is useful for shifting the body center-of-mass
laterally onto the leading stance limb while simultaneously unloading the
trailing limb. However, exaggerated lateral trunk flexion may introduce an
unstable scenario if the XCoM is displaced beyond the lateral base-of-support.
Further studies would be useful to identify if either prostheses that assist limb
advancement and/or gait training may be effective in reducing this lateral sway
while still maintaining efficient ambulation.
CI - Copyright (c) 2013 Elsevier B.V. All rights reserved.

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