Testing of a Biomechanical Model of the Lumbar Muscle Force Distribution Using Quasi-Static Loading Exercises

1992 ◽  
Vol 114 (4) ◽  
pp. 442-449 ◽  
Author(s):  
Z. Ladin ◽  
K. M. Neff
Keyword(s):  
Muscle Force ◽  
Biomechanical Model ◽  
Design Tool ◽  
Emg Activity ◽  
Force Distribution ◽  
Lumbar Region ◽  
Erect Posture ◽  
Biomechanical Models ◽  
Lumbar Muscle ◽  
The Subject

The study of lumbar muscle force distribution in response to externally applied loads is based on the introduction of biomechanical models of the lumbar region. The evaluation of such models requires the execution of loading exercises while monitoring the EMG activity of certain lumbar muscles. This work uses muscle activity maps as the major design tool of such exercises, provided that the subject is constrained to an upright erect posture. The maps describe the predicted muscle force for a given combination of externally applied bending moments. A series of shoulder adduction exercises were designed and the EMG signals of eight lumbar muscles were measured while subjects performed the exercises. The results show good agreement between the model predictions and the EMG measurements, especially when the load and the muscle were contralateral to one another.

The Effects of External Bending Moments on Lumbar Muscle Force Distribution

1991 ◽  
Vol 113 (3) ◽  
pp. 284-294 ◽  
Author(s):  
Z. Ladin ◽  
K. R. Murthy ◽  
C. J. De Luca
Keyword(s):  
Three Dimensional ◽  
Biomechanical Model ◽  
External Loading ◽  
Low Back ◽  
Bending Moments ◽  
Erect Posture ◽  
Switching Curve ◽  
Lumbar Muscle ◽  
The Individual ◽  
Comprehensive Framework

A detailed biomechanical model of the low-back musculature that predicts muscleforce distribution in response to external loading is presented. The paper shows that the class of loading tasks that involve an erect posture and an arbitrary load placed on the upper limbs can be described as a loading plane whose axes are the flexion and lateral bending moments. Under these conditions, the individual muscle forces are described as a three-dimensional surface defined by the loading plane and termed the muscle activity surface (MAS). The MAS and the loading plane intersect along the switching curve which separates the load combinations that activate the muscle from those that do not. The paper suggests the existence of a recruitment order of low back muscles in response to external loads and presents a comprehensive framework for examining earlier studies that used EMG measurements to validate physiological and mechanical predictions.

Effect of upper limb position and loading on lumbar muscle force distribution

1987 ◽  
Vol 20 (9) ◽  
pp. 894 ◽  
Author(s):  
Kurukundi R. Murthy ◽  
Zvi Ladin ◽  
Carlo J. De Luca
Keyword(s):  
Upper Limb ◽  
Muscle Force ◽  
Force Distribution ◽  
Limb Position ◽  
Lumbar Muscle

scholarly journals Reduced biomechanical models for precision-cut lung-slice stretching experiments

2021 ◽  
Vol 82 (5) ◽  
Author(s):  
Hannah J. Pybus ◽  
Amanda L. Tatler ◽  
Lowell T. Edgar ◽  
Reuben D. O’Dea ◽  
Bindi S. Brook
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Ex Vivo ◽  
Finite Thickness ◽  
Biomechanical Model ◽  
Local Stress ◽  
Smooth Muscle Contraction ◽  
Biomechanical Models ◽  
Cytokine Activation ◽  
Asymptotic Reduction

AbstractPrecision-cut lung-slices (PCLS), in which viable airways embedded within lung parenchyma are stretched or induced to contract, are a widely used ex vivo assay to investigate bronchoconstriction and, more recently, mechanical activation of pro-remodelling cytokines in asthmatic airways. We develop a nonlinear fibre-reinforced biomechanical model accounting for smooth muscle contraction and extracellular matrix strain-stiffening. Through numerical simulation, we describe the stresses and contractile responses of an airway within a PCLS of finite thickness, exposing the importance of smooth muscle contraction on the local stress state within the airway. We then consider two simplifying limits of the model (a membrane representation and an asymptotic reduction in the thin-PCLS-limit), that permit analytical progress. Comparison against numerical solution of the full problem shows that the asymptotic reduction successfully captures the key elements of the full model behaviour. The more tractable reduced model that we develop is suitable to be employed in investigations to elucidate the time-dependent feedback mechanisms linking airway mechanics and cytokine activation in asthma.

Impact of Age and Body Mass Index on Anthropometry in Working Adults

2017 ◽  
Vol 61 (1) ◽  
pp. 1341-1345 ◽  
Author(s):  
Zachary Merrill ◽  
April Chambers ◽  
Rakié Cham
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Center Of Mass ◽  
Biomechanical Model ◽  
Whole Body ◽  
Working Adults ◽  
Biomechanical Models ◽  
Scan Data ◽  
Body Segment Parameters ◽  
The Impact

Body segment parameters (BSPs) such as segment mass and center of mass are used as inputs in ergonomic design and biomechanical models to predict the risk of musculoskeletal injuries. These models have been shown to be sensitive to the BSP values used as inputs, demonstrating the necessity of using accurate and representative parameters. This study aims to provide accurate BSPs by quantifying the impact of age and body mass index on torso and thigh mass and center of mass in working adults using whole body dual energy x-ray absorptiometry (DXA) scan data. The results showed significant effects of gender, age, and body mass index (BMI) on torso and thigh mass and center of mass, as well as significant effects of age and BMI within genders, indicating that age, gender, and BMI need to be taken into account when predicting BSPs in order to calculate representative ergonomic and biomechanical model outputs.

scholarly journals Effects of Cultured Adrenal Chromaffin Cell Implants on Hindlimb Reflexes of the6-OHDA Lesioned Rat

1994 ◽  
Vol 5 (2) ◽  
pp. 89-102 ◽  
Author(s):  
Bruce E. Pulford ◽  
Andrea R. Mihajlov ◽  
Howard O. Nornes ◽  
L. Ray Whalen
Keyword(s):  
Spinal Cord ◽  
Glyoxylic Acid ◽  
Reflex Activity ◽  
Emg Activity ◽  
Lumbar Region ◽  
Adrenal Chromaffin Cell ◽  
Electrophysiological Testing ◽  
Withdrawal Reflexes ◽  
6 Hydroxydopamine ◽  
Adrenal Chromaffin

The effects of implantation of cultured adrenal medullary cells on the recovery of neurotransmitter specific reflex activity were studied in the rat spinal cord using electrophysiological testing methods. Cell suspensions of cultured neonatal adrenal medullary chromaffin (AM) cells (which produce catecholamines), or Schwann (Sc) cells (controls) were implanted into the lumbar region of the spinal cord 2 weeks after catecholamine (CA) denervation by intracisternal injection of 6-hydroxydopamine (6-OHDA). All cells were taken from 7 day neonates and cultured for 10 days in the presence of nerve growth factor (NGF). Three months after implantation, the extent of implant-associated recovery of reflex activity was determined by measuring electromyogram (EMG) activity and force associated with the long latency component of the hindlimb withdrawal reflex (which is CA modulated). After the electrophysiological testing, rats were anesthetized, and the spinal cords were rapidly removed and frozen. Spinal cords were sectioned longitudinally, and implanted cells were visualized using glyoxylic acid techniques. Labelled sections were examined to determine cell survival. Results indicate that 1) chromaffin cells survive for 3 months in the segments of the cord into which they have been implanted and 2) rats implanted with AM cells have significantly more forceful withdrawal reflexes than those that received Sc cells or received no implant after lesioning.

scholarly journals The Applications of Mathematics and Modular Art in the Education of Interior Design

2018 ◽  
Vol 13 (1) ◽  
pp. 36
Author(s):  
Mayyadah Fahmi Hussein
Keyword(s):  
Interior Design ◽  
Latin Square ◽  
Design Tool ◽  
Basic Design ◽  
Pattern Design ◽  
Experimental Procedure ◽  
Practical Applications ◽  
Advantages And Disadvantages ◽  
New Learning ◽  
The Subject

The new learning processes should be piloted therefore; Interior design schools should be updated according to the results of progress in teaching methods. For this reason, the objective of this study is to define the formulation of a mixed learning model for mathematics applications and technical models within the interior educational system. This paper’s main objective is to find explanations of incorporating the cotemporary interior design within the Mathematics & Modular art content, and to seek modern solutions featuring as new methods. This paper was carried out by experimental procedure in University of Petra/Department of Interior Design based on basic design courses in the academic years 2011-2012 where the researcher took a sample of ten student forms based on the models which were chosen in this experiment combining both difficulty & ease. The students have completed these ten shapes by altering mathematical approach (Latin square) to create a new pattern design. Art with Mathematical approaches have been applied in different practical applications as a basic design tool, and conclusions have been reached on the merits of the design. The advantages and disadvantages of teaching interior design have been introduced from Art & mathematical perspective as a method of design based on the results found during the practical applications of basic design projects and from information in publications on the subject. Relying on these proposed models, the proposals will constantly develop design tools. In conclusion, educating future designers to digest the essence of these approaches will make it possible to train professionals who correctly use and understand the developed technologies that can create futuristic designs.

scholarly journals Spatiotemporal distribution of location and object effects in the electromyographic activity of upper extremity muscles during reach-to-grasp

2016 ◽  
Vol 115 (6) ◽  
pp. 3238-3248 ◽  
Author(s):  
Adam G. Rouse ◽  
Marc H. Schieber
Keyword(s):  
Upper Extremity ◽  
Muscle Activity ◽  
Neural Control ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Proximal Muscle ◽  
Reach To Grasp ◽  
Distal Muscle ◽  
The Subject ◽  
Later Phase

In reaching to grasp an object, proximal muscles that act on the shoulder and elbow classically have been viewed as transporting the hand to the intended location, while distal muscles that act on the fingers simultaneously shape the hand to grasp the object. Prior studies of electromyographic (EMG) activity in upper extremity muscles therefore have focused, by and large, either on proximal muscle activity during reaching to different locations or on distal muscle activity as the subject grasps various objects. Here, we examined the EMG activity of muscles from the shoulder to the hand, as monkeys reached and grasped in a task that dissociated location and object. We quantified the extent to which variation in the EMG activity of each muscle depended on location, on object, and on their interaction—all as a function of time. Although EMG variation depended on both location and object beginning early in the movement, an early phase of substantial location effects in muscles from proximal to distal was followed by a later phase in which object effects predominated throughout the extremity. Interaction effects remained relatively small. Our findings indicate that neural control of reach-to-grasp may occur largely in two sequential phases: the first, serving to project the entire upper extremity toward the intended location, and the second, acting predominantly to shape the entire extremity for grasping the object.

scholarly journals Characterization of rat tail lymphatic contractility and biomechanics: incorporating nitric oxide-mediated vasoregulation

2020 ◽  
Vol 17 (170) ◽  
pp. 20200598 ◽  
Author(s):  
Mohammad S. Razavi ◽  
J. Brandon Dixon ◽  
Rudolph L. Gleason
Keyword(s):  
Nitric Oxide ◽  
Mechanical Response ◽  
Contractile Function ◽  
Ex Vivo ◽  
Biomechanical Model ◽  
Biomechanical Models ◽  
Lymphatic Pumping ◽  
Rat Tail ◽  
Lymphatic Contractility

The lymphatic system transports lymph from the interstitial space back to the great veins via a series of orchestrated contractions of chains of lymphangions. Biomechanical models of lymph transport, validated with ex vivo or in vivo experimental results, have proved useful in revealing novel insight into lymphatic pumping; however, a need remains to characterize the contributions of vasoregulatory compounds in these modelling tools. Nitric oxide (NO) is a key mediator of lymphatic pumping. We quantified the active contractile and passive biaxial biomechanical response of rat tail collecting lymphatics and changes in the contractile response to the exogenous NO administration and integrated these findings into a biomechanical model. The passive mechanical response was characterized with a three-fibre family model. Nonlinear regression and non-parametric bootstrapping were used to identify best-fit material parameters to passive cylindrical biaxial mechanical data, assessing uniqueness and parameter confidence intervals; this model yielded a good fit ( R 2 = 0.90). Exogenous delivery of NO via sodium nitroprusside (SNP) elicited a dose-dependent suppression of contractions; the amplitude of contractions decreased by 30% and the contraction frequency decreased by 70%. Contractile function was characterized with a modified Rachev–Hayashi model, introducing a parameter that is related to SNP concentration; the model provided a good fit ( R 2 = 0.89) to changes in contractile responses to varying concentrations of SNP. These results demonstrated the significant role of NO in lymphatic pumping and provide a predictive biomechanical model to integrate the combined effect of mechanical loading and NO on lymphatic contractility and mechanical response.

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