Dynamic balance during walking adaptability tasks in individuals post-stroke
Maintaining dynamic balance during community ambulation is a major challenge post-stroke. Community ambulation requires performance of steady-state level walking as well as tasks that require walking adaptability. Prior studies on balance control post-stroke have mainly focused on steady-state walking, but walking adaptability tasks have received little attention. The purpose of this study was to quantify and compare dynamic balance requirements during common walking adaptability tasks post-stroke and in healthy adults and identify differences in underlying mechanisms used for maintaining dynamic balance. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 23, 2018 Category: Biomedical Science Authors: Arian Vistamehr, Chitralakshmi K. Balasubramanian, David J. Clark, Richard R. Neptune, Emily J. Fox Source Type: research
Proteoglycans Contribute Locally to Swelling, but Globally to Compressive Mechanics, in Intact Cervine Medial Meniscus
Loss of charged proteoglycans in the knee meniscus, which aid in the support of compressive loads by entraining water, is an effect of degeneration and is often associated with osteoarthritis. In healthy menisci, proteoglycan content is highest in the inner white zone and decreases towards the peripheral red zone. We hypothesized that loss of proteoglycans would reduce both osmotic swelling and compressive stiffness, spatially localized to the avascular white zone of the meniscus. This hypothesis was tested by targeted enzymatic digestion of proteoglycans using hyaluronidase in intact cervine medial menisci. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 23, 2018 Category: Biomedical Science Authors: Arthur J. Michalek, Laurel Kuxhaus, Daniel Jaremczuk, Nicole L Zaino Source Type: research
Dynamic balance during walking adaptability tasks in individuals post-stroke
Maintaining dynamic balance during community ambulation is a major challenge post-stroke. Community ambulation requires performance of steady-state level walking as well as tasks that require walking adaptability. Prior studies on balance control post-stroke have mainly focused on steady-state walking, but walking adaptability tasks have received little attention. The purpose of this study was to quantify and compare dynamic balance requirements during common walking adaptability tasks post-stroke and in healthy adults and identify differences in underlying mechanisms used for maintaining dynamic balance. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 23, 2018 Category: Biomedical Science Authors: Arian Vistamehr, Chitralakshmi K. Balasubramanian, David J. Clark, Richard R. Neptune, Emily J. Fox Source Type: research
Multi-View Stereo in the Operating Room Allows Prediction of Healing Complications in a Patient-Specific Model of Reconstructive Surgery
Excessive mechanical stress leads to wound healing complications following reconstructive surgery. However, this knowledge is not easily applicable in clinical scenarios due to the difficulty in measuring stress contours during complex tissue rearrangement procedures. Computational tools have been proposed as an alternative to address this need, but obtaining patient specific geometries with an affordable and flexible setup has remained a challenge. Here we present a methodology to determine the stress contours from a reconstructive procedure on a patient-specific finite element model based on multi-view stereo (MVS). (Sou...
Source: Journal of Biomechanics - April 20, 2018 Category: Biomedical Science Authors: Taeksang Lee, Sergey Y. Turin, Arun K Gosain, Adrian Buganza Tepole Source Type: research
The control structure of the nematode Caenorhabditis elegans: Neuro-sensory integration and proprioceptive feedback
We develop a biophysically realistic model of the nematode C. elegans that includes: (i) its muscle structure and activation, (ii) key connectomic activation circuitry, and (iii) a weighted and time-dynamic proprioception. In combination, we show that these model components can reproduce the complex waveforms exhibited in C. elegans locomotive behaviors, chiefly omega turns. This is achieved via weighted, time-dependent suppression of the proprioceptive signal. Though speculative, such dynamics are biologically plausible due to the presence of neuromodulators which have recently been experimentally implicated in the escape...
Source: Journal of Biomechanics - April 18, 2018 Category: Biomedical Science Authors: C. Fieseler, J. Kunert-Graf, J.N. Kutz Source Type: research
The control structure of the nematode Caenorhabditis elegans: neuro-sensory integration and proprioceptive feedback
We develop a biophysically realistic model of the nematode C. elegans that includes: (i) its muscle structure and activation, (ii) key connectomic activation circuitry, and (iii) a weighted and time-dynamic proprioception. In combination, we show that these model components can reproduce the complex waveforms exhibited in C. elegans locomotive behaviors, chiefly omega turns. This is achieved via weighted, time-dependent suppression of the proprioceptive signal. Though speculative, such dynamics are biologically plausible due to the presence of neuromodulators which have recently been experimentally implicated in the escape...
Source: Journal of Biomechanics - April 18, 2018 Category: Biomedical Science Authors: C. Fieseler, J. Kunert-Graf, J.N. Kutz Source Type: research
Ankle and foot power in gait analysis: Implications for science, technology and clinical assessment
In human gait analysis studies, the entire foot is typically modeled as a single rigid-body segment; however, this neglects power generated/absorbed within the foot. Here we show how treating the entire foot as a rigid body can lead to misunderstandings related to (biological and prosthetic) foot function, and distort our understanding of ankle and muscle-tendon dynamics. We overview various (unconventional) inverse dynamics methods for estimating foot power, partitioning ankle vs. foot contributions, and computing combined anklefoot power. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 17, 2018 Category: Biomedical Science Authors: Karl E. Zelik, Eric C. Honert Tags: Review Source Type: research
Effect of pelvis impact angle on stresses at the femoral neck during falls
Improved understanding is required of how the mechanics of the fall affect hip fracture risk. We used a hip impact simulator to determine how peak stresses at the femoral neck were affected by pelvis impact angle, hip abductor muscle force, and use of a wearable hip protector.We simulated falls from standing (2 m/s impact velocity) involving initial hip abductor muscle forces of 700 or 300 N. Trials were acquired for impact to the lateral aspect of the greater trochanter, and impact to the pelvis rotated 5°, 10° and 15° anteriorly (positive) or posteriorly (negative). (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 16, 2018 Category: Biomedical Science Authors: W.J. Choi, S.N. Robinovitch Source Type: research
Finite element modeling of the human kidney for probabilistic occupant models: Statistical shape analysis and mesh morphing
Statistical shape analysis was conducted on 15 pairs (left and right) of human kidneys. It was shown that the left and right kidney were significantly different in size and shape. In addition, several common modes of kidney variation were identified using statistical shape analysis. Semi-automatic mesh morphing techniques have been developed to efficiently create subject specific meshes from a template mesh with a similar geometry. Subject specific meshes as well as probabilistic kidney meshes were created from a template mesh. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 16, 2018 Category: Biomedical Science Authors: Keegan M. Yates, Costin D. Untaroiu Source Type: research
Effect of pelvis impact angle on stresses at the femoral neck during falls
Improved understanding is required of how the mechanics of the fall affect hip fracture risk. We used a hip impact simulator to determine how peak stresses at the femoral neck were affected by pelvis impact angle, hip abductor muscle force, and use of a wearable hip protector.We simulated falls from standing (2 m/s impact velocity) involving initial hip abductor muscle forces of 700 or 300 N. Trials were acquired for impact to the lateral aspect of the greater trochanter, and impact to the pelvis rotated 5 °, 10° and 15° anteriorly (positive) or posteriorly (negative). (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 16, 2018 Category: Biomedical Science Authors: W.J. Choi, S.N. Robinovitch Source Type: research
Finite Element Modeling of the human kidney for probabilistic occupant models: Statistical shape analysis and mesh morphing
Statistical shape analysis was conducted on 15 pairs (left and right) of human kidneys. It was shown that the left and right kidney were significantly different in size and shape. In addition, several common modes of kidney variation were identified using statistical shape analysis. Semi-automatic mesh morphing techniques have been developed to efficiently create subject specific meshes from a template mesh with a similar geometry. Subject specific meshes as well as probabilistic kidney meshes were created from a template mesh. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 16, 2018 Category: Biomedical Science Authors: Keegan Yates, Costin Untaroiu Source Type: research
A new method to quantify liner deformation within a prosthetic socket for below knee amputees
Many amputees who wear a leg prosthesis develop significant skin wounds on their residual limb. The exact cause of these wounds is unclear as little work has studied the interface between the prosthetic device and user. Our research objective was to develop a quantitative method for assessing displacement patterns of the gel liner during walking for patients with transtibial amputation. Using a reflective marker system and a custom clear socket, evaluations were conducted with a clear transparent test socket mounted over a plaster limb model and a deformable limb model. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 13, 2018 Category: Biomedical Science Authors: Amy L. Lenz, Katie A. Johnson, Tamara Reid Bush Tags: Short communication Source Type: research
A New Method to Quantify Liner Deformation within a Prosthetic Socket for Below Knee Amputees
Many amputees who wear a leg prosthesis develop significant skin wounds on their residual limb. The exact cause of these wounds is unclear as little work has studied the interface between the prosthetic device and user. Our research objective was to develop a quantitative method for assessing displacement patterns of the gel liner during walking for patients with transtibial amputation. Using a reflective marker system and a custom clear socket, evaluations were conducted with a clear transparent test socket mounted over a plaster limb model and a deformable limb model. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - April 13, 2018 Category: Biomedical Science Authors: Amy L. Lenz, Katie A. Johnson, Tamara Reid Bush Tags: Short communication Source Type: research
