Quantitative assessment of gait determinants during single stance via a three-dimensional model--Part 2. Pathological gait.
A three-dimensional model for normal gait formulated in Part 1 is now altered to simulate the dynamics of pathological walking. Mechanisms fundamental to the production of a normal gait pattern are systematically removed, in order to assess contributions from individual gait determinants. Four separate pathological cases are studied: a model neglecting ankle plantarflexor activity; absence of stance knee flexion-extension and foot and knee interaction; both pelvic list and transverse pelvic rotation removed; and finally, a model with all major gait determinants missing. These are used collectively to show that stance knee flexion-extension and foot and knee interaction successively dominate lower-extremity dynamical response during the single support phase of normal gait. The hip abductor muscles, while effecting pelvic list, serve to stabilize this limb, rather than actively determine whole-body vertical acceleration. Mechanisms compensating for a loss in joint motion are also explored. Complete ankle loss may be successfully compensated with increased hip abductor muscle activity; the loss of both ankle and knee, however, demand unacceptable levels of vertical pelvic displacement.
Pandy
M G
MG
Mechanical Engineering Department, Stanford University, CA 94305.
Berme
N
N
D000328:Adult; D000843:Ankle Joint / Q000502:physiology; D005528:Foot / Q000503:physiopathology; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008124:Locomotion / Q000502:physiology; D008297:Male; D008954:Models, Biological; D009069:Movement Disorders / Q000503:physiopathology; D009132:Muscles / Q000502:physiology; D012399:Rotation