The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Sebastian Dendorfer - One of the best experts on this subject based on the ideXlab platform.
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Sensitivity of Lumbar Spine loading to anatomical parameters
Journal of biomechanics, 2015Co-Authors: Michael Putzer, Ingo Ehrlich, John Rasmussen, Norbert Gebbeken, Sebastian DendorferAbstract:Musculoskeletal simulations of Lumbar Spine loading rely on a geometrical representation of the anatomy. However, this data has an inherent inaccuracy. This study evaluates the influence of defined geometrical parameters on Lumbar Spine loading utilising five parametrised musculoskeletal Lumbar Spine models for four different postures. The influence of the dimensions of vertebral body, disc, posterior parts of the vertebrae as well as the curvature of the Lumbar Spine was studied. Additionally, simulations with combinations of selected parameters were conducted. Changes in L4/L5 resultant joint force were used as outcome variable. Variations of the vertebral body height, disc height, transverse process width and the curvature of the Lumbar Spine were the most influential. These parameters can be easily acquired from X-rays and should be used to morph a musculoskeletal Lumbar Spine model for subject-specific approaches with respect to bone geometry. Furthermore, the model was very sensitive to uncommon configurations and therefore, it is advised that stiffness properties of discs and ligaments should be individualised.
Brian Dunlap - One of the best experts on this subject based on the ideXlab platform.
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A follower load increases the load-carrying capacity of the Lumbar Spine in compression
Spine, 1999Co-Authors: Avinash G. Patwardhan, Kevin P. Meade, Robert M. Havey, Brian Lee, Brian DunlapAbstract:STUDY DESIGN An experimental approach was used to test human cadaveric Spine specimens. OBJECTIVE To assess the response of the whole Lumbar Spine to a compressive follower load whose path approximates the tangent to the curve of the Lumbar Spine. SUMMARY OF BACKGROUND DATA Compression on the Lumbar Spine is 1000 N for standing and walking and is higher during lifting. Ex vivo experiments show it buckles at 80-100 N. Differences between maximum ex vivo and in vivo loads have not been satisfactorily explained. METHODS A new experimental technique was developed for applying a compressive follower load of physiologic magnitudes up to 1200 N. The experimental technique applied loads that minimized the internal shear forces and bending moments, made the resultant internal force compressive, and caused the load path to approximate the tangent to the curve of the Lumbar Spine. RESULTS A compressive vertical load applied in the neutral lordotic and forward-flexed postures caused large changes in Lumbar lordosis at small load magnitudes. The specimen approached its extension or flexion limits at a vertical load of 100 N. In sharp contrast, the Lumbar Spine supported a load of up to 1200 N without damage or instability when the load path was tangent to the spinal curve. CONCLUSIONS Until this study, an experimental technique for applying compressive loads of in vivo magnitudes to the whole Lumbar Spine was unavailable. The load-carrying capacity of the Lumbar Spine sharply increased under a compressive follower load, as long as the load path remained within a small range around the centers of rotation of the Lumbar segments. The follower load path provides an explanation of how the whole Lumbar Spine can be lordotic and yet resist large compressive loads. This study may have implications for determining the role of trunk muscles in stabilizing the Lumbar Spine.
Kim L. Bennell - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional angular kinematics of the Lumbar Spine and pelvis during running
Human movement science, 2002Co-Authors: Anthony G. Schache, Peter Blanch, David A Rath, Tim V. Wrigley, Kim L. BennellAbstract:The objective of this study were to: (i) describe the typical three-dimensional (3D) angular kinematics of the Lumbar Spine and pelvis during running and; (ii) assess whether the movements of the Lumbar Spine and pelvis during running are coordinated. A cohort of 20 non-injured male runners who usually ran >20 km/week were voluntarily recruited. All trials were conducted on a treadmill at a running speed of 4.0 m/second. Reflective markers were placed over anatomical landmarks of the thoraco-Lumbar Spine and pelvis. Data were captured using a VICON motion analysis system. The Lumbar Spine and pelvis both displayed complex 3D angular kinematic patterns during running. High correlations were found for the comparisons of flexion-extension of the Lumbar Spine with anterior-posterior tilt of the pelvis (r=-0.84) and lateral bend of the Lumbar Spine with obliquity of the pelvis (r=-0.75). However, a poor correlation was found for the comparison of axial rotation of the Lumbar Spine with axial rotation of the pelvis (r=0.37). A phase difference of 21% of the running cycle was evident between axial rotation of the Lumbar Spine and pelvis. The identified coordinated kinematic patterns of the Lumbar Spine and pelvis during running serve as a basis for future investigations exploring the relationship between atypical kinematic patterns and injury.
Michael Putzer - One of the best experts on this subject based on the ideXlab platform.
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Sensitivity of Lumbar Spine loading to anatomical parameters
Journal of biomechanics, 2015Co-Authors: Michael Putzer, Ingo Ehrlich, John Rasmussen, Norbert Gebbeken, Sebastian DendorferAbstract:Musculoskeletal simulations of Lumbar Spine loading rely on a geometrical representation of the anatomy. However, this data has an inherent inaccuracy. This study evaluates the influence of defined geometrical parameters on Lumbar Spine loading utilising five parametrised musculoskeletal Lumbar Spine models for four different postures. The influence of the dimensions of vertebral body, disc, posterior parts of the vertebrae as well as the curvature of the Lumbar Spine was studied. Additionally, simulations with combinations of selected parameters were conducted. Changes in L4/L5 resultant joint force were used as outcome variable. Variations of the vertebral body height, disc height, transverse process width and the curvature of the Lumbar Spine were the most influential. These parameters can be easily acquired from X-rays and should be used to morph a musculoskeletal Lumbar Spine model for subject-specific approaches with respect to bone geometry. Furthermore, the model was very sensitive to uncommon configurations and therefore, it is advised that stiffness properties of discs and ligaments should be individualised.
Avinash G. Patwardhan - One of the best experts on this subject based on the ideXlab platform.
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A follower load increases the load-carrying capacity of the Lumbar Spine in compression
Spine, 1999Co-Authors: Avinash G. Patwardhan, Kevin P. Meade, Robert M. Havey, Brian Lee, Brian DunlapAbstract:STUDY DESIGN An experimental approach was used to test human cadaveric Spine specimens. OBJECTIVE To assess the response of the whole Lumbar Spine to a compressive follower load whose path approximates the tangent to the curve of the Lumbar Spine. SUMMARY OF BACKGROUND DATA Compression on the Lumbar Spine is 1000 N for standing and walking and is higher during lifting. Ex vivo experiments show it buckles at 80-100 N. Differences between maximum ex vivo and in vivo loads have not been satisfactorily explained. METHODS A new experimental technique was developed for applying a compressive follower load of physiologic magnitudes up to 1200 N. The experimental technique applied loads that minimized the internal shear forces and bending moments, made the resultant internal force compressive, and caused the load path to approximate the tangent to the curve of the Lumbar Spine. RESULTS A compressive vertical load applied in the neutral lordotic and forward-flexed postures caused large changes in Lumbar lordosis at small load magnitudes. The specimen approached its extension or flexion limits at a vertical load of 100 N. In sharp contrast, the Lumbar Spine supported a load of up to 1200 N without damage or instability when the load path was tangent to the spinal curve. CONCLUSIONS Until this study, an experimental technique for applying compressive loads of in vivo magnitudes to the whole Lumbar Spine was unavailable. The load-carrying capacity of the Lumbar Spine sharply increased under a compressive follower load, as long as the load path remained within a small range around the centers of rotation of the Lumbar segments. The follower load path provides an explanation of how the whole Lumbar Spine can be lordotic and yet resist large compressive loads. This study may have implications for determining the role of trunk muscles in stabilizing the Lumbar Spine.
