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Steve C. Miff
Northwestern University
7Publications
6H-index
559Citations
Publications 7
Newest
#1Andrew H. Hansen (NU: Northwestern University)H-Index: 22
#2Steve C. Miff (NU: Northwestern University)H-Index: 6
Last.Margrit R. Meier (NU: Northwestern University)H-Index: 9
view all 5 authors...
The net external energy of the biologic human ankle joint and of some lower limb prosthetic ankle-foot systems was examined during gait initiation. The purpose of the study was to better understand the ankle's behavior during the acceleration phase of walking for use in the design of improved lower limb prostheses and orthoses. Quantitative gait data were collected from 10 able-bodied subjects and 10 persons with unilateral transtibial amputations during gait initiation. The behaviors of the bio...
10 CitationsSource
#1Steve C. Miff (NU: Northwestern University)H-Index: 6
#2Andrew H. Hansen (NU: Northwestern University)H-Index: 22
Last.Margrit R. Meier (NU: Northwestern University)H-Index: 9
view all 5 authors...
A few investigators have described the movement of the center of pressure (COP) of the ground reaction force and the activation patterns of the lower limb muscles during gait initiation and termination. This study examines the effective rocker (roll-over shape) behavior of the knee-ankle-foot (KAF) system during gait initiation, steady-state walking (i.e. constant speed gait), and gait termination. The KAF roll-over shapes were characterized by transforming COP data of 10 able-bodied subjects fr...
15 CitationsSource
#1Steve C. Miff (NU: Northwestern University)H-Index: 6
#2Dudley S. Childress (NU: Northwestern University)H-Index: 25
Last.Andrew H. HansenH-Index: 22
view all 5 authors...
This study investigated the temporal characteristics of gait initiation and gait termination. Ten nondisabled adult vol- unteers and ten people with unilateral transtibial limb loss per- formed starting and stopping for slow, normal, and fast walking speeds. We used kinematic and anthropomorphic data to deter- mine the body center of mass (BCOM) position of each subject. The BCOM acceleration was derived by double-differentiating the position data. An averaged BCOM acceleration was calcu- lated ...
26 CitationsSource
#1Andrew H. Hansen (NU: Northwestern University)H-Index: 22
#2Dudley S. Childress (NU: Northwestern University)H-Index: 25
Last.Steve C. Miff (NU: Northwestern University)H-Index: 6
view all 3 authors...
Abstract Roll-over characteristics of able-bodied human subjects walking on ramped surfaces were examined in this study. Ten subjects walked at their normal self-selected speed on a level surface, a 5-deg ramp, and a 10-deg ramped surface. Ramps were designed such that ground reaction forces and center of pressure of the ground reaction forces could be measured on their surfaces. This set-up facilitated calculation of the effective rockers that the ankle–foot (AF) and knee–ankle–foot (KAF) syste...
53 CitationsSource
#1Andrew H. Hansen (NU: Northwestern University)H-Index: 22
#2Dudley S. Childress (NU: Northwestern University)H-Index: 25
Last.Kent P. MesplayH-Index: 1
view all 5 authors...
Abstract The non-disabled human ankle joint was examined during walking in an attempt to determine overall system characteristics for use in the design of ankle prostheses. The hypothesis of the study was that the quasi-stiffness of the ankle changes when walking at different walking speeds. The hypothesis was examined using sagittal plane ankle moment versus ankle angle curves from 24 able-bodied subjects walking over a range of speeds. The slopes of the moment versus ankle angle curves (quasi-...
267 CitationsSource
#1Steven A. Gard (NU: Northwestern University)H-Index: 23
#2Steve C. Miff (NU: Northwestern University)H-Index: 6
Last.Arthur D. Kuo (UM: University of Michigan)H-Index: 45
view all 3 authors...
The vertical excursion of the body center of mass (BCOM) was calculated using three different techniques commonly used by motion analysis laboratories. The sacral marker method involved estimating vertical BCOM motion by tracking the position of a reflective marker that was placed on the sacrum of subjects as they walked. The body segmental analysis technique determined the vertical motion of the BCOM from a weighted average of the vertical positions of the centers of mass of individual body seg...
185 CitationsSource
#1Steve C. Miff (NU: Northwestern University)H-Index: 6
#2Steven A. GardH-Index: 23
Last.D.S. Childress (NU: Northwestern University)H-Index: 5
view all 3 authors...
Gait analysis is useful in the evaluation and treatment of musculoskeletal and neurological disorders, and it is beneficial in the assessment of prosthetic and orthotic performance during walking. An understanding of the relationship between step length, cadence, walking speed, and vertical excursion of the trunk can help in analyzing and comparing healthy and pathological gait. Theoretical and empirical relationships between the vertical excursion and walking speed were analyzed for freely sele...
3 CitationsSource
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