Shawn D. Russell

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Recently, researchers in robotics have used regulation of the angular momentum of body segments about the total body center of mass (CoM) to develop control strategies for bipedal gait. This work was spurred by reports finding that for a "large class" of human movement tasks, including standing, walking, and running the angular momentum is conserved about(More)
Three computer models of varying complexity were developed in order to investigate the kinematics, kinetics, muscle operating ranges, and energetics of rock climbing. First, inverse dynamic models were used to investigate the joint angles and torques used in climbing and to quantify the total mechanical work required for typical rock climbing. Climbing(More)
We studied the coordination of body segments during treadmill walking. Specifically, we used the uncontrolled manifold hypothesis framework to quantify the segmental angular momenta (SAM) synergies that stabilize (i.e., reduce the across trials variability) the whole body angular momentum (WBAM). Seven male subjects were asked to walk over a treadmill at(More)
This paper describes a method to characterize gait pathologies like cerebral palsy using work, energy, and angular momentum. For a group of 24 children, 16 with spastic diplegic cerebral palsy and 8 typically developed, kinematic data were collected at the subjects self selected comfortable walking speed. From the kinematics, the work-internal, external,(More)
BACKGROUND Studies suggest that 50% of children with cerebral palsy are prescribed ankle foot orthoses. One of the aims of ankle foot orthosis use is to aid in walking. This research examined the effects that ankle foot orthoses have on the energy recovery and the mechanical work performed by children with cerebral palsy during walking. METHODS Twenty-one(More)
Some unicellular organisms present challenges to chemical fixations that lead to common, yet obvious, artifacts. These can be avoided in entirety by adapting spray-freezing technology to ultrarapidly freeze specimens for freeze substitution. To freeze specimens, concentrated suspensions of cells ranging in diameter from 0.5-30 pm were sprayed with an(More)
In the present study, we quantified the isolated contributions of eight determinants of gait on the vertical center of mass (CoM) displacement of both typically developing children and children with cerebral palsy (CP). The role of these determinants, on vertical excursion, has never been examined for children or children with CP. We hypothesized that the(More)
Gait disorders drastically affect the quality of life of stroke survivors, making post-stroke rehabilitation an important research focus. Noninvasive brain stimulation has potential in facilitating neuroplasticity and improving post-stroke gait impairment. However, a large inter-individual variability in the response to noninvasive brain stimulation(More)