Showing papers in "Journal of Biomechanics in 1981"

TL;DR: The inversely-nonlinear relationship of muscle contraction force and the possible contraction duration is utilized in a method to mathematically predict individual muscle forces and shows substantial agreement with that activity pattern predicted when endurance is used as the optimization criterion.

TL;DR: Serial cross-sectional anatomy analysis was used to obtain the centroid and thus the moment arms of each of the muscles along the upper arm and at the elbow joint, and physiological cross-sections were calculated.

TL;DR: Improvements on existing approaches were found to be more crucially dependent on the accurate determination of joint angles and the calculation of joint torques than on the particular optimization criteria employed.

TL;DR: A processing method is presented by which the surface electromyogram can be processed to the muscle force, irrespective of the type of contraction.

TL;DR: Musculoskeletal data suitable for use in biomechanical analyses of hip function are presented by marking the approximate locations of hip muscle attachment points on the bony pelvis and right femur of an adult, male, dry bone specimen.

TL;DR: A mathematical model is presented which makes it possible to simulate complex motions of a 17-segment hominoid and not only fully accounts for the dynamics of the executor (skeletal) subsystem but also simulates in detail the intricately controlled internal excitation and contraction Dynamics of the myoactuator (muscular) sybsystem.

TL;DR: The methodology presented may serve as a simple diagnostic tool for early revealing of the deficiency of the subject's locomotion system and may allow some preventive action to be taken to delay or cancel the process of joint degeneration.

TL;DR: This technique, although especially developed for the in vitro study of the three-dimensional flexibility measurements of the spine segments, may be advantageously utilized in other situations where small three- dimensional motion needs to be studied with high accuracy and in real-time.

TL;DR: The displacement of points lying on the longitudinal axis of the upper part of the human body at head, shoulder and pelvis level was estimated in the three dimensions of space during level walking on a straight line at speeds ranging from 0.99 to 2.79 m s−1.

TL;DR: During normal human gait the lower limb is subjected to a high frequency impulsive load at heel strike using both force plates having a high resonant frequencies and a force transducer inserted into the heel of the shoe of the subjects.

TL;DR: The coherent “starting structure” of poststenotic flow disturbances may have relevance in reducing the threshold of recognition of developing atherosclerotic plaques.

TL;DR: Calculations revealed that an inverse relationship exists, between the intensity and duration of external pressure required for the interstitial fluid volume in the pressurized region to reach a given portion of its initial volume, which is similar to the experimentally observed relationship between theintensity and duration to produce threshold damage.

TL;DR: It was demonstrated in model experiments that, if the pulsatility of theMitral flow is maintained, the mitral valve closure remains unaffected even in absence of large vortices behind valve leaflets.

TL;DR: The results suggest that the fatigue strength of cortical bone at 107 cycles may be closer to 7 than 40 MPa as indicated by previous bending fatigue tests and that fatigue is more strongly controlled by strain range than stress range.

TL;DR: A mathematical representation of the human leg during the swing phase of gait was developed that employed variables which were known to be clinically significant physical, anatomical and physiological features influencing the gait pattern.

TL;DR: A unique, highly accurate, non-contacting method for measuring the loaded and unloaded shape and thickness of acetabular articular cartilage employing ultrasound is described, showing the unloaded cartilage surface to be spherical with localized deviations less than 150 μm.

TL;DR: A computer-based instrumentation system was used to accurately measure the six foot-pedal load components and the absolute pedal position during bicycling and yielded the following major conclusions: using cleated shoes retards fatigue of the quadriceps muscle group.

TL;DR: The results indicate that compressive stress is of minor importance with respect to the etiology of idiopathic osteoarthrosis of the hip joint.

TL;DR: An optimally regularized (filtered) Fourier series can be used most effectively for estimating higher-order derivatives of noisy data sequences, such as occur in biomechanical investigations.

TL;DR: A new instrumentation system to precisely measure pedal loads and pedal position is presented, designed to mount on most bicycles without modification and offers three degree-of-freedom adjustability.

TL;DR: Values for the r.m.s. and the peak error in the isotonic phases of the contraction are given and compared with values predicted from the stochastic properties of the EMG signal.

TL;DR: It is believed that the highly irregular pressure profiles observed are due primarily to cartilage thickness distribution and irregularities at the calcified cartilage interface as described in Part I.

TL;DR: A new two-layer cylindrical model is proposed to describe the nonlinear properties of carotid arteries and the agreement between experimental and theoretical curves lies within 2% accuracy which cannot be achieved with single-layer models.

TL;DR: Tetracycline labeling of these animals suggest that a strong relationship exists between the altered stress field and the distribution of bone remodeling induced by plate application, and that the midshaft stress distributions at a particular instant of time during the stance phase of the gait cycle were calculated.

TL;DR: The parameters of the active state and the series-elastic component of the Hill muscle model were estimated for the human calf muscles by means of a ‘torque plate’ on seven normal subjects and this yields the complete set of parameters for the EMG to force processor based on the Hill model.

TL;DR: Theoretical predictions of surface bone remodeling in the diaphysis of a long bone under a constant superposed compressive load are made and it is shown that there is a great variety of solutions to the problem.

TL;DR: A positive correlation was observed between mean tether force and velocity in the crawl, particularly among distance specialists, and a negative correlation was found between crawl velocity and the peak/mean force ratio.

TL;DR: Test on control, decalcified and deproteinized groups of specimens demonstrated that the post-yield or ‘plastic’ slope of the stress-strain curve for unaltered bone is dependent on collagen properties, while the elastic modulus and yield phenomenon appear more dependent on the mineral phase.