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OBJECTIVE It was our primary objective to provide evidence supporting the existence of neural detectors for postural instability that could trigger the compensatory adjustments to avoid falls. METHODS Twelve young healthy subjects performed self-initiated oscillatory and discrete postural movements in the anterior-posterior (AP) directions with maximal(More)
OBJECTIVE To assess gait in patients with autism. DESIGN Clinical and physiologic assessment. SETTING Research hospital. PATIENTS AND SUBJECTS Five adults with autism and five healthy, age-matched control subjects. MAIN OUTCOME MEASURE(S) Clinical and biomechanical assessment. RESULTS Clinical assessment showed mild clumsiness in four patients and(More)
In standing humans, it is not certain whether anticipatory postural adjustments associated with rapid, voluntary elbow flexion movements (focal movements) originate as a selection from preset synergies or as the result of specific planning of motor commands. We studied these muscle recruitment patterns when the same focal movement was made under behavioral(More)
The overall goal of this work was to determine an optimal surface-tracking marker set for tracking motion of the tibia during natural cadence walking. Eleven different marker sets were evaluated. The marker sets differed in the location they were attached to the shank, the method used to attach the marker sets to the segment and the physical characteristics(More)
BACKGROUND The ability to redirect the path of the foot during walking is critical for responding to perturbations and maintaining upright stability. The purpose of the current study was to compare mechanisms of reactive stepping adjustments in young versus older adults when responding to an unexpected perturbation during voluntary step initiation. (More)
Normal subjects performed bilaterally symmetric rapid elbow flexions or extensions ("focal movements") while standing. Specific patterns of electromyographic activity in leg and trunk muscles ("associated postural adjustments") were seen for each type of movement. The biomechanical significance of these postural adjustments was analysed by means of the(More)
The effect soft tissue movement of the shank had on knee joint moments during natural cadence walking was investigated in this study. This was examined by comparing knee moments determined from bone-anchored and surface mounted tracking targets. Six healthy adult subjects participated in this study. The largest difference (3 N m) occurred about the AP axis,(More)
This study examined the relationship between lower extremity dominance and kinematic symmetry during gait. Fourteen healthy volunteers without any observable gait deviations participated in the study. The subjects (8 male, 6 female) ranged in age from 19 to 56 years. Lower extremity lateral dominance was determined using an assessment method developed by(More)
A technique to measure foot function during the stance phase of gait is described. Advantages of the method include its three-dimensional approach with anatomically based segment coordinate systems. This allows variables such as ground reaction forces and center of pressure location to be expressed in a local foot coordinate system, which gives more(More)
This study was designed to demonstrate that an accurate and reliable technique for measuring the rotational motion between rigid bodies can be developed from a video-based data collection system. Tests on the accuracy of the rotational measurements demonstrated that for each of five trials, under three test condition, mean errors of less than 0.4 degrees(More)