Showing papers in "Journal of Biomechanics in 1988"

TL;DR: The Young's modulus of elasticity, the calcium content and the volume fraction (1-porosity) of 23 tension specimens and 80 bending specimens, taken from compact bone of 18 species of mammal, bird and reptile, were determined.

TL;DR: This paper presents a statistical analysis of the pooled data from a number of previous experiments concerning the dependence of the Young's moduli and strength of cancellous bone tissue upon apparent density and it is concluded that the suggestion of Wolff that compact bone tissue is simply more dense cancellousBone tissue is not an accurate statement.

TL;DR: The extensor muscles about the knee played a dominant role in progression from one step to the next in both modes coupled with the ankle plantar flexors, and the total lower limb extensor pattern, called the support moment, was highly correlated between subjects and to level walking.

TL;DR: Data indicate that small changes in the amount or density of compact bone tissue exert a more pronounced influence on its stiffness than would similar changes in trabecular bone.

TL;DR: For vertical jumping the relationships between muscle actions, movement pattern and jumping achievement, and the EMG-pattern to the purpose of the push-off, were investigated to maximize the effective energy (Ey) of the mass center of the body (MCB).

TL;DR: Sagittal plane biomechanical and EMG analyses from eight below knee (B/K) amputee trials demonstrate considerably modified motor patterns from the residual muscles at the hip and knee as discussed by the authors.

TL;DR: An algorithm for estimating the translation vector and the rotation matrix of a moving body from noisy measurements on the spatial co-ordinates of at least three non-collinear markers is described.

TL;DR: An accurate experimental database for the passive (in vitro) freedom-of-motion characteristics of the human knee joint is created on a subject to subject basis, suitable for the verification and enhancement of mathematical knee-joint models.

TL;DR: An ultrasonic technique was used to measure both the elastic modulus (Young's modulus) of trabecular bone material and the elasticmodulus of the cancellous structure and on human and bovine specimens the structural elasticModulus was found to be related to the structural (apparent) density raised to the 1.88 power.

TL;DR: A three-dimensional mathematical model of the human masticatory system, containing 16 muscle forces and two joint reaction forces, is described, which predicts that at each specific bite point, bite forces can be generated in a wide range of directions, and that the magnitude of the maximum bite force depends on its direction.

TL;DR: Dgenerated cervical discs were less stiff in compression and stiffer in shear than less degenerated discs, but in bending or axial torsion, no statistically significant differences were evident.

TL;DR: A criterion for the validity of the assumption that cancellous bone can be modelled as a continuum is developed, resulting in an estimate of density accuracy as a function of line length which is experimentally verified.

TL;DR: An estimation of the relative importance of the various synergistic muscle properties during dynamic movement tasks is provided, aided by examples of muscle load-sharing as a function of optimization criteria including measures of position error, muscle stress and neural effort.

TL;DR: The analysis suggests that the cement line is a region of reduced mineralization which may contain sulfated mucosubstances, which is consistent with the hypothesis thatThe cement line provides a relatively ductile interface with surrounding bone matrix, and that it provides the point specific stiffness differences, poor 'fiber'-matrix bonding and energy transfer qualities required to promote crack initiation but slow crack growth in compact bone.

TL;DR: It is demonstrated that by carefully considering the magnitudes of imposed skeletal forces and the number of loading cycles, it may be possible to design exercise programs to achieve predictable changes in bone mass.

TL;DR: The magnetic position and orientation tracking system has been found to be quite accurate and easy to use, and it would be a useful tool in kinesiologic research.

TL;DR: This paper presents a linear programming optimization technique that solves a two-objective problem with two sequential linear programs, and uses the technique here to minimize muscle intensity and joint compression force.

TL;DR: Two modified DLT algorithms are presented that improve the accuracy of three-dimensional object space reconstruction by almost an order of magnitude when compared with conventional methods.

TL;DR: System identification techniques have been used to track changes in dynamic stiffness of the human ankle joint over a wide range of muscle contraction levels and found the elastic parameter (K) increased in proportion to mean ankle torque as it was varied from rest to MVC; changes were considerable involving increases of more than an order of magnitude.

TL;DR: Strain energy stored in the muscle-tendon unit during the yield phase in early stance is felt to be a major contributor to the muscle's enhanced mechanical output during muscle shortening in late stance.

TL;DR: The elastin fibers of rat skin samples were degraded by the use of a purified preparation ofElastase to which soybean inhibitor was added, preventing the collagenolytic activity of the elastase on collagen.

TL;DR: The Viscous criterion accurately predicts the risk of vital organ and soft tissue injury when other criteria fail, and is shown to be an indicator of the energy dissipated by soft tissue deformation.

TL;DR: It was found that Fd is related to the swimming velocity v raised to the power 2.12 +/-0.20 (males) or 2.28 +/- 0.35 (females).

TL;DR: The purpose of this study was to add to the growing database of cross-sectional areas and moment arm lengths of trunk musculature using the methods of computerized tomographic scanning and an attempt was made to estimate muscle force and moment generating capacity under various reported values of muscle force per unit cross-section.

TL;DR: The repeatability of measures of seat-to-head transmissibility within a single subject and the variability inTransmissibility across a group of twelve subjects have been determined with two seating conditions: a rigid seat with a backrest and the same seat with no backrest.

TL;DR: A computer model of 23 knees was obtained by embedding, slicing and digitizing the bone outlines and ligament co-ordinates, with significant deviations for abnormal motions including the elimination of internal-external rotation and a-p displacement and the misplacement of a hinge producing correct motion.

TL;DR: This study demonstrates that FQ does not equal FP as several authors have reported, and the difference in FQ and FP influences both the magnitude and direction of PFJR.

TL;DR: It was found that a major portion of the inelastic strain is always recovered on unloading and that the accumulation of creep strain increases the material compliance on subsequent loadings below the threshold, suggesting that a damage mechanism is responsible for the nonlinear behavior.