Showing papers in "Journal of Biomechanics in 1995"

TL;DR: It was concluded that the method developed offers new perspectives for the study of trabecular bone, which uses three-dimensional serial reconstruction techniques to construct a large-scale FE model, by directly converting voxels to elements.

TL;DR: Since 1990, the Standardization and Terminology Committee of the International Society of Biomechanics has been working towards a recommendation for standardization in the reporting of kinematic data, and the use of center of mass-based segmental reference frames should be routinely used.

TL;DR: A numerical model for the blood flow in the human carotid artery bifurcation has been developed and the comparison of the results for a rigid and a distensible wall model demonstrates quantitative influence of the vessel wall motion.

TL;DR: In this paper, a 3D inverse dynamics model of the lower limbs and power profiles were derived using a dot product of the angular velocities and joint moments resolved in a global reference system.

TL;DR: The paper presents a new procedure for the determination of these parameters, which requires the coordinates of three or more non-collinear points, and provides a least-squares estimate of the rigid body transformation parameters.

TL;DR: The results suggest that the actin cytoskeleton plays an important role in the link between compression of the extracellular matrix and deformation of the chondrocyte nuclei and imply that chONDrocytes and their nuclei undergo significant changes in shape and volume in vivo.

TL;DR: The anatomical studies and the computer model demonstrate that the biceps flexion moment arm peaks in a more extended elbow position and has a larger peak when the forearm is supinated, and the peak biceps supination moment arm decreases as the elbow is extended.

TL;DR: The results emphasize the importance of matrix-dependent changes in cell and nuclear shape as well as higher order structural interactions between different cytoskeletal filament systems for control of capillary cell growth during angiogenesis.

TL;DR: The influence of muscle activation, position and velocities of body segments at touchdown and surface properties on impact forces during heel-toe running was investigated using a direct dynamics simulation technique.

TL;DR: Finite element analyses of the pelvic bone are used to investigate its basic load transfer and stress distributions under physiological loading conditions and show that the major part of the load is transferred through the cortical shell.

TL;DR: There may be significant regional nonhomogeneity of fiber stress in the normal left ventricle associated with regional variations in shape and fiber angle, unlike in the midventricle region that has been studied most fully.

TL;DR: A similar model, but one in which the effects of fluid dynamic drag of the cell surface matrix in the bone canaliculi are included, is used to show that it is possible for the generation of SGPs to be associated with the larger size lacunar-canalicular porosity when the hydraulic drag and electrokinetic contribution of the bone fluid passage through the cell coat is considered.

TL;DR: Changes in stiffness associated with reduction of disk diameter suggested that the relative contributions of collagen and proteoglycans to cartilage mechanical properties may be a function of loading frequency in unconfined compression; such anisotropies may explain the remaining discrepencies between measured stiffness and stiffness predicted by the present model.

TL;DR: A model was developed to accurately simulate multi-dimensional spinal loads and trunk moments from measured muscle coactivity and external forces during free-dynamic lifting exertions to examine realistic representations of lifting kinetics, kinematics, and dynamic trunk mechanics that may influence spinal loading and to demonstrate that EMG-assisted modeling techniques can be applied to the analysis of free-Dynamic exertions.

TL;DR: A simple, inexpensive footswitch system that provides accurate estimates of the start and end of stance phase for sequential steps is developed that should prove to be a useful tool for augmenting laboratory based investigations of gait.

TL;DR: Whether the same estimates of individual muscle and L4/L5 lumbar joint compressive forces result from an optimization compared to an electromyography (EMG) assisted approach for solving the inderminate moment equilibrium equations in the same anatomical model is determined.

TL;DR: Regression analysis showed that only three parameters, the elastic modulus, the maximum strain, and the strain intersect, are sufficient to define the nonlinear stress-strain relation up to failure.

TL;DR: The solidification methodology combines the numerical benefits of the least-squares method with the conceptual benefits of a rigid body method to address segmental kinematic errors in video-based motion analysis systems.

TL;DR: It was found that crack growth range, thickness and material assumptions affect fracture toughness, and the toughness of human and bovine bone are roughly similar, but the data were not sufficiently definitive to answer the question of which is tougher.

TL;DR: An in vitro mechanical load model is used to test the hypothesis that tendon cells require platelet-derived growth factor and insulin-like growth factor in addition to mechanical load to stimulate DNA synthesis and it is demonstrated that in avian tendon cells, load and growth factors stimulate phosphorylation of tyrosine residues in multiple proteins.

TL;DR: A sagittal-plane model of the lower limb, which considered the possibility of antagonistic and synergistic muscle action and took account of the load-bearing roles of the cruciate ligaments, was applied to a dynamic analysis of level walking, predicted remarkably similar patterns of muscle activity over the gait cycle.

TL;DR: An anatomical anthropometric study of adult human cadaveric pelves was performed to investigate the relationship between hip joint center (HJC) and selected aspects of pelvic geometry, and it was revealed that HJC cannot be accurately located as a function of pelvic width alone, but requires estimation as afunction of pelvic height and depth as well.

TL;DR: The application of a hybrid approach, sonoelastography, which uses ultrasound to measure the propagation of shear waves induced by externally applied vibrations is reported on, which is anticipated to provide a useful adjunct to the study of human biomechanics.

TL;DR: A theoretical solution is obtained for another common loading of articular cartilage, namely the contact of surfaces in rolling motion, and the protective stress-shielding effect of interstitial fluid pressurization may become less effective in diseased tissue.

TL;DR: Fast goal directed arm movements in the sagittal plane were analyzed with a three-dimensional shoulder model with 95 muscle elements and most model results were similar to the EMG but some differences between model results and EMG were found in muscles where theEMG activity was subject dependent.

TL;DR: The outlines of the extended inverse dynamics method are presented, the constraints which define walking are defined, the optimization procedure is described and the model is applied to analyze a normal walking pattern of which only the hip, knee and ankle flexions/extensions are measured.

TL;DR: Using bovine aortic endothelium monolayers, it is shown that fluid shear stress causes simultaneous differential regulation of endothelial-derived products and that the downregulation of endothelin-1 mRNA by flow is a reversible process.

TL;DR: Torsional moments now observed in vivo are close to or even exceed the experimentally determined limits of the torsional strength of implant fixations, found in the literature.

TL;DR: It was hypothesized that gait transitions are effected to prevent overexertion of the dorsiflexor muscles that perform at or near maximum capacity during fast walking (at the PTS) during human locomotion.

TL;DR: A method (EBRA) is described that evaluates standard AP radiographs without requiring additional means at exposure (e.g. ball markers) and computes parameters of longitudinal and transverse migration of prosthetic cup and femoral head.