scholarly journals Running Form Analysis Based on Impact Dynamics: A Minimally Complex Mechanical Model

2018 ◽  
Vol 63 (1) ◽  
pp. 7-15 ◽  
Author(s):  
László Bencsik ◽  
Ambrus Zelei
Keyword(s):  
Degrees Of Freedom ◽  
Biomechanical Model ◽  
Total Body Weight ◽  
The Body ◽  
Body Parts ◽  
Form Analysis ◽  
Biomechanical Models ◽  
Foot Strike ◽  
Low Degrees ◽  
The Impact

Biomechanical models of different complexity are used to understand the dynamics of human running. Low degrees-of-freedom models are appropriate for the prediction of the effect of certain parameter changes. We present a minimally complex biomechanical model which characterizes the effects of foot strike pattern and shank angle on the ground-foot impact intensity, which influences the risk of injuries and energy efficiency.A three segment leg model (thigh, shank and foot) is proposed combined with the mass of the rest of the body parts concentrated in the hip. The ground-foot impact intensity and the absorbed kinetic energy are analyzed using multibody dynamics tools. The impact intensity was discovered in the parameter space of the angle of the thigh, the angle of the shank, the foot strike pattern and the running speed.The results regarding the effect of strike pattern are in coincidence with the literature: forefoot strike implies lower impact intensity and energy absorption than rearfoot strike. However, in contrast of the previous result of a two segment foot model from the related literature, the calculations indicated that the shank angle highly affects the impact intensity: the impact intensity can be reduced by foot touchdown under the hip. We showed that foot and shank cannot be analyzed in itself without considering the thigh and the total body weight, and we also confirmed that the horizontal velocity cannot be neglected when foot impact is analyzed.

scholarly journals A Two Joint Neck Model to Identify Malposition of the Head Relative to the Thorax

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3297
Author(s):  
Philipp M. Schmid ◽  
Christoph M. Bauer ◽  
Markus J. Ernst ◽  
Bettina Sommer ◽  
Lars Lünenburger ◽  
...  
Keyword(s):  
Neck Pain ◽  
Body Height ◽  
Biomechanical Model ◽  
The Body ◽  
Head Orientation ◽  
Neck Length ◽  
Proposed Model ◽  
Biofeedback System ◽  
Simple Measurement ◽  
The Impact

Neck pain is a frequent health complaint. Prolonged protracted malpositions of the head are associated with neck pain and headaches and could be prevented using biofeedback systems. A practical biofeedback system to detect malpositions should be realized with a simple measurement setup. To achieve this, a simple biomechanical model representing head orientation and translation relative to the thorax is introduced. To identify the parameters of this model, anthropometric data were acquired from eight healthy volunteers. In this work we determine (i) the accuracy of the proposed model when the neck length is known, (ii) the dependency of the neck length on the body height, and (iii) the impact of a wrong neck length on the models accuracy. The resulting model is able to describe the motion of the head with a maximum uncertainty of 5 mm only. To achieve this high accuracy the effective neck length must be known a priory. If however, this parameter is assumed to be a linear function of the palpable neck length, the measurement error increases. Still, the resulting accuracy can be sufficient to identify and monitor a protracted malposition of the head relative to the thorax.

Maximizing Recall of Gruesome Images for Health Effects Advertising: An Experimental Investigation

2010 ◽  
Vol 16 (4) ◽  
pp. 112-121 ◽  
Author(s):  
Brennen W. Mills ◽  
Owen B. J. Carter ◽  
Robert J. Donovan
Keyword(s):  
Experimental Investigation ◽  
Body Part ◽  
The Body ◽  
Advertising Effectiveness ◽  
Body Parts ◽  
Online Study ◽  
Video Clips ◽  
Video Images ◽  
The Impact

The objective of this case study was to experimentally manipulate the impact on arousal and recall of two characteristics frequently occurring in gruesome depictions of body parts in smoking cessation advertisements: the presence or absence of an external physical insult to the body part depicted; whether or not the image contains a clear figure/ground demarcation. Three hundred participants (46% male, 54% female; mean age 27.3 years, SD = 11.4) participated in a two-stage online study wherein they viewed and responded to a series of gruesome 4-s video images. Seventy-two video clips were created to provide a sample of images across the two conditions: physical insult versus no insult and clear figure/ground demarcation versus merged or no clear figure/ground demarcation. In stage one, participants viewed a randomly ordered series of 36 video clips and rated how “confronting” they considered each to be. Seven days later (stage two), to test recall of each video image, participants viewed all 72 clips and were asked to identify those they had seen previously. Images containing a physical insult were consistently rated more confronting and were remembered more accurately than images with no physical insult. Images with a clear figure/ground demarcation were rated as no more confronting but were consistently recalled with greater accuracy than those with unclear figure/ground demarcation. Makers of gruesome health warning television advertisements should incorporate some form of physical insult and use a clear figure/ground demarcation to maximize image recall and subsequent potential advertising effectiveness.

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.

An appropriate biomechanical model of seated human subjects exposed to whole-body vibration

2021 ◽  
pp. 146441932110394
Author(s):  
Raj Desai ◽  
Anirban Guha ◽  
Pasumarthy Seshu
Keyword(s):  
Degrees Of Freedom ◽  
Human Subjects ◽  
Computational Cost ◽  
Biomechanical Model ◽  
Whole Body ◽  
Body Parts ◽  
Lumped Parameter ◽  
Long Duration ◽  
The One ◽  
The Right

Long duration automobile-induced vibration is the cause of many ailments to humans. Predicting and mitigating these vibrations through seat requires a good model of seated human body. A good model is the one that strikes the right balance between modelling difficulty and simulation results accuracy. Increasing the number of body parts which have been separately modelled and increasing the number of ways these parts are connected to each other increase the number of degrees of freedom of the entire model. A number of such models have been reported in the literature. These range from simple lumped parameter models with limited accuracy to advanced models with high computational cost. However, a systematic comparison of these models has not been reported till date. This work creates eight such models ranging from 8 to 26 degrees of freedom and tries to identify the model which strikes the right balance between modelling complexity and results accuracy. A comparison of the models’ prediction with experimental data published in the literature allows the identification of a 12 degree of freedom backrest supported model as optimum for modelling complexity and prediction accuracy.

scholarly journals Optical Wireless Network Design for Off-Body-Sensor Based Monitoring

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
T. B. Hoang ◽  
S. Sahuguede ◽  
A. Julien-Vergonjanne
Keyword(s):  
Health Monitoring ◽  
Visible Light Communication ◽  
The Body ◽  
Sensor Data ◽  
Body Parts ◽  
Optical Technology ◽  
Wireless Network Design ◽  
Response Sets ◽  
Trade Offs ◽  
The Impact

In this article, we propose an all-optical bidirectional wireless communication system for off-body sensor communication. Optical technology uses infrared (IR) for uplinks and visible light communication (VLC) for downlinks. From numerical simulations, we discuss the impact of body sensor positions on IR and VLC channels. Our goal is to evaluate the possibilities of using optical technology to transmit sensor data for extreme positions such as the ankle, for which the presence of the body creates blockages. In addition, we also consider the variations in orientation of transceivers due to random mobility of body parts during normal movement. Based on a statistical approach, we evaluate performance in terms of outage probability using channel impulse response sets corresponding to the studied scenario, which is health monitoring. Considering a given quality of service, we address trade-offs related to emitting power and data rate. We discuss the results regarding sensor node position and body reflectivity specifically for ankle sensors, corresponding to an extreme but realistic position in the health-monitoring context.

Theoretical Study of the Water Entry of a Body in Waves: Application to Safety of Occupants in Free-Fall Lifeboats

2009 ◽  
Author(s):  
Thomas Sauder ◽  
Se´bastien Fouques
Keyword(s):  
Water Waves ◽  
Degrees Of Freedom ◽  
Mass Matrix ◽  
Free Fall ◽  
Theoretical Method ◽  
Emergency Evacuation ◽  
Momentum Conservation ◽  
The Body ◽  
Water Impact ◽  
The Impact

The safety of occupants in free-fall lifeboats (FFL) during water impact is addressed. The first part of the paper describes a theoretical method developed to predict the trajectory in six degrees of freedom of a body entering water waves. Slamming forces and moments are computed, based on momentum conservation, long wave approximation and a von Karman type of approach. The added mass matrix of the body is evaluated for impact conditions by a boundary element method. The second part of the paper focuses on the application of the method to free-fall lifeboats, which are used for emergency evacuation of oil platforms or ships. Acceleration loads on FFL occupants during water impact are dependent on numerous parameters, especially the hull shape, the mass distribution, the wave heading relative to the lifeboat, and the impact point on the wave surface. Assessing operational limits of FFL by means of model tests only has therefore been costly and time consuming. This issue is addressed here by applying the theoretical method described in the first part. The model has been validated for FFL through extensive model testing in calm water and regular waves, and statistical estimates of acceleration levels for lifeboat occupants, as well as acceleration time series were obtained that can be used as inputs to numerical human response models.

scholarly journals Oblique impact of a smooth body on a thin layer of inviscid liquid

2013 ◽  
Vol 469 (2151) ◽  
pp. 20120615 ◽  
Author(s):  
T. I. Khabakhpasheva ◽  
A. A. Korobkin
Keyword(s):  
Body Surface ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Hydrodynamic Pressure ◽  
Oblique Impact ◽  
The Body ◽  
Second Stage ◽  
Smooth Body ◽  
Vertical Displacements ◽  
The Impact

The two-dimensional motion of a rigid body with a smooth surface is studied during its oblique impact on a liquid layer. The problem is coupled: the three degrees of freedom of the moving body are determined together with the liquid flow and the hydrodynamic pressure along the wetted part of the body surface. The impact process is divided into two temporal stages. During the first stage, the wetted region expands at a high speed with jetting flows at both ends of the wetted region. In the second stage, the free surface of the liquid is allowed to separate from the body surface. The position of the separation point is determined with the help of the Brillouin–Villat condition. Calculations are performed for elliptic cylinders of different masses and with different orientations and speeds before the impact. The horizontal and vertical displacements of the body, as well as its angle of rotation and corresponding speeds are investigated. The model developed remains valid until the body either touches the bottom of the liquid or rebounds from the liquid.

Kinematic Analysis of a Five-Legged Mobile Robot

2010 ◽  
Author(s):  
Muhammed R. Pac ◽  
Dan O. Popa
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Parallel Robots ◽  
The Body ◽  
Legged Robots ◽  
Upper Body ◽  
Design Changes ◽  
Robot Performance ◽  
The Impact

Legged robots are more maneuverable, and can negotiate rough terrain much better than conventional locomotion using wheels. However, since the kinematic or dynamic analysis of such robots involves closed chains, it is typically more difficult to investigate the impact of design changes, such as the number, or the design of its legs, to robot performance. Most legged robots consist of 4 legs (quadrupeds) or 6 legs (hexapods). This paper discusses the kinematic analysis of an unconventional, symmetrical 5-legged robot with 2-DOF (Degrees Of Freedom) universal joints in each leg. The analysis was carried out in order to predict the mobility of the upper body platform, and investigate the number of robot actuators needed for mobility. The product of exponentials formulation with respect to the local coordinate frames is used to describe the twists of the joints. The analysis is based on the idea that the robot body platform along with the legs can be considered instantaneously as a parallel robot manipulating the ground. Hence, the analysis can be done using the Jacobian formulation of parallel robots. Simulation results confirm the mobility analysis that the robot can have at most 3-DOF for the body and that these freedoms are coupled rotations and translations in 3D space also with a dependence on the configuration of the robot.

A Computationally Efficient Muscle Model

2012 ◽  
Author(s):  
Matthew Millard ◽  
Scott Delp
Keyword(s):  
Degrees Of Freedom ◽  
Biomechanical Model ◽  
Muscle Model ◽  
Computationally Efficient ◽  
State Equations ◽  
Explicit Integration ◽  
Biomechanical Models ◽  
Complex Models ◽  
Complex Joint ◽  
Simulation Time

Modern biomechanical models often include many degrees of freedom, complex joint geometry, and hundreds of muscles [1]. Such complex models may provide realistic representations of musculoskeletal dynamics, but they require a great deal of time to simulate. The state equations of the muscles are frequently the stiffest numerical element in a biomechanical model and determine the simulation time. Here we introduce a muscle model that generates similar forces as a conventional muscle model, but requires fewer explicit integration steps.

scholarly journals Bringing Objectification into Social Relationships Research: Is Self-Objectification Harmful for Authenticity?

2016 ◽  
Vol 19 ◽  
Author(s):  
Chiara Rollero
Keyword(s):  
Social Relationships ◽  
Past Research ◽  
The Body ◽  
Body Parts ◽  
Negative Consequences ◽  
Appearance Anxiety ◽  
Step Model ◽  
And Performance ◽  
Self Objectification ◽  
The Impact

AbstractSelf-objectification is a pervasive process in contemporary Western societies and psychological literature has largely shown its negative consequences in terms of body shame, appearance anxiety, mental health and performance. Mass media play a key role in promoting such process through the extensive sexualization of individuals’ body and the separation of sexualized body parts from the rest of the body. The purpose of the present study was to extend past research by examining the effects of self-objectification in the context of social relationships among young adults. Participants were 235 undergraduates (55.7% females). A three-step model was successfully tested: results showed that internalization of media standards is related to increased self-objectification (β = .33, SE = .08, p = .01), which in turn is associated with authenticity, being high self-objectifiers less devoted to authentic living (β = –.21, SE = .09, p = .01) and more self-alienated (β = .14, SE = .08, p = .04) and dependent on others’ influence (β = .50, SE = .01, p = .01). The pattern of these relationships did not significantly vary across gender (χ2 = 6.29; p = .18). Implications concerning the impact of self-objectification in the domain of social relationships are discussed.

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