Reducing Dynamic Loads From a Backpack During Load Carriage Using an Upper Body Assistive Device

2016 ◽  
Vol 8 (5) ◽  
Author(s):  
Joon-Hyuk Park ◽  
Paul Stegall ◽  
Sunil K. Agrawal
Keyword(s):  
Dynamic Load ◽  
Controller Design ◽  
Load Carriage ◽  
Lower Limbs ◽  
Dynamic Loads ◽  
Assistive Device ◽  
Upper Body ◽  
Single Subject ◽  
Preliminary Evaluation ◽  
Heavy Loads

This paper presents studies of an upper body assistive device designed to aid human load carriage. The two primary functions of the device are: (i) distributing the backpack load between the shoulders and the waist and (ii) reducing the dynamic load of a backpack on the human body during walking. These functions are targeted to relieve stress applied on the shoulders and the back, and also reduce the dynamic loads transferred to the lower limbs during walking. These functions are achieved by incorporating two modules—passive and active—within a custom fitted shirt integrated with motion/force sensors, actuators, and a real-time controller. The relevant modeling and controller design are presented for dynamic load compensation. Preliminary evaluation of the device was first performed on a single subject, followed by a pilot study with ten healthy subjects walking on a treadmill with a backpack. Results show that the device can effectively transfer the load from the shoulders to the waist and also reduce the dynamic loads induced by the backpack during walking. Reduction in peak and total normal ground reaction forces, leg muscle activations, and oxygen consumptions was observed with the device. This suggests that the device can potentially reduce the risk of musculoskeletal injuries and fatigue on the lower limbs associated with carrying heavy loads and provide some metabolic benefits.

Second Spine: Upper Body Assistive Device for Human Load Carriage

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Joon-Hyuk Park ◽  
Xin Jin ◽  
Sunil K. Agrawal
Keyword(s):  
Human Motion ◽  
Musculoskeletal Injuries ◽  
Load Carriage ◽  
Assistive Device ◽  
Upper Body ◽  
Human Walking ◽  
Inertia Force ◽  
Concept Design ◽  
Test Bed ◽  
Heavy Load

This study presents the development of second spine, an upper body assistive device for human load carriage. The motivation comes from reducing musculoskeletal injuries caused by carrying a heavy load on the upper body. Our aim was to design a wearable upper body device that can prevent musculoskeletal injuries during human load carriage by providing a secondary load pathway—second spine—to transfer the loads from shoulders to pelvis while also allowing a good range of torso motion to the wearer. Static analysis of the backpack and the second spine was first performed to investigate the feasibility of our concept design. The development of second spine had two considerations: load distribution between shoulders and pelvis, and preserving the range of torso motion. The design was realized using load bearing columns between the shoulder support and hip belt, comprising multiple segments interconnected by cone-shaped joints. The performance of second spine was evaluated through experimental study, and its biomechanical effects on human loaded walking were also assessed. Based on the findings from second spine evaluation, we proposed the design of a motorized second spine which aims to compensate the inertia force of a backpack induced by human walking through active load modulation. This was achieved by real-time sensing of human motion and actuating the motors in a way that the backpack motion is kept nearly inertially fixed. Simulation study was carried out to determine the proper actuation of motors in response to the human walking kinematics. The performance of motorized second spine was evaluated through an instrumented test-bed using Instron machine. Results showed a good agreement with simulation. It was shown that the backpack motion can be made nearly stationary with respect to the ground which can further enhance the effectiveness of the device in assisting human load carriage.

Wearable Upper Body Suit for Assisting Human Load Carriage

2015 ◽  
Author(s):  
Joon-Hyuk Park ◽  
Paul Stegall ◽  
Sunil K. Agrawal ◽  
Shridhar Yarlagadda ◽  
John Tierney ◽  
...  
Keyword(s):  
Dynamic Load ◽  
Load Distribution ◽  
Vertical Motion ◽  
Load Carriage ◽  
Upper Body ◽  
Human Walking ◽  
System Response ◽  
Cable Tension ◽  
Load Bearing ◽  
Backpack Load

This paper presents a wearable upper body suit designed to assist in human load carriage. The two functions of the suit are: (i) load distribution between the shoulders and the waist, and (ii) reduction of the dynamic load on the waist during walking. These are achieved through two cable driven modules — passive and active — within a custom fitted shirt integrated with motion/force sensors, actuators, and a real time controller. The load distribution between the shoulders and the waist is achieved through the load bearing columns connecting the shoulder pads and the waist belt whose load bearing capacity is modulated by a nominal cable tension in the passive module via a ratchet mechanism. The dynamic load is reduced in addition in the active module by modulating the cable tension via external actuator. Mathematical model of the system is presented and a state feedback controller is designed. Simulation study was performed to investigate the system response under different disturbance conditions as a result of vertical motion of the waist during human walking. Experiment evaluation of the suit was performed with a subject walking on a treadmill while carrying a backpack load. The results show that the developed suit can transfer the load from the shoulders to the waist as well as reduce the dynamic load induced during human walking. This can potentially reduce the energy expenditure and the risk of musculoskeletal injuries associated with human load carriage.

Mid-aortic syndrome: computed tomography angiography depicting extensive collateral circulation in an 11-year-old patient with thoracoabdominal aortic coarctation

VASA ◽  
2012 ◽  
Vol 41 (2) ◽  
pp. 132-135 ◽  
Author(s):  
Krohn ◽  
Gebauer ◽  
Hübler ◽  
Beck
Keyword(s):  
Computed Tomography ◽  
Computed Tomography Angiography ◽  
Collateral Circulation ◽  
Intestinal Ischemia ◽  
Clinical Presentation ◽  
Lower Limbs ◽  
Upper Body ◽  
Descending Aorta ◽  
Before And After ◽  
Blood Pressures

The mid-aortic syndrome is an uncommon clinical condition characterized by severe narrowing of the descending aorta, usually with involvement of its renal and visceral branches, presenting with uncontrollably elevated blood pressures of the upper body, renal and cardiac failure, intestinal ischemia, encephalopathy symptoms and claudication of the lower limbs, although clinical presentation is variable. In this article we report the case of an eleven-year-old patient with the initial diagnosis of a mid-aortic syndrome and present the computed tomography angiography pictures and reconstructions before and after surgical therapy.

Congenital Syphilis Simulating Bone Neoplasm in 2-Month Old Infant – Case Report

2017 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Case Report ◽  
Congenital Syphilis ◽  
Eosinophilic Granuloma ◽  
Osteolytic Lesion ◽  
Lower Limbs ◽  
Upper Body ◽  
Elective Cesarean Section ◽  
Distal Fibula ◽  
X Ray

Introduction: Congenital Syphilis (CS) occurs through the transplacental transmission of Treponema pallidum in inadequately treated or non-treated pregnant women, and is capable of severe consequences such as miscarriage, preterm birth, congenital disease and/or neonatal death. CS has been showing an increasing incidence worldwide, with an increase of 208% from 2009 to 2015 in Brazil. Case report: 2-month old infant receives care in emergency service due to edema of right lower limb with pain in mobilization. X-ray with osteolytic lesion in distal fibula. Infant was sent to the Pediatrics Oncology clinic. Perinatal data: 7 prenatal appointments, negative serology at 10 and 30 weeks of gestation. End of pregnancy tests were not examined and tests for mother’s hospital admission were not requested. Mother undergone elective cesarean section at 38 weeks without complications. During the pediatric oncologist appointment, patient showed erythematous-squamous lesions in neck and other scar-like lesions in upper body. A new X-ray of lower limbs showed lesions in right fibula with periosteal reaction associated with aggressive osteolytic lesion compromising distal diaphysis, with cortical bone rupture and signs of pathological fracture, suggestive of eosinophilic granuloma. She was hospitalized for a lesion biopsy. Laboratory tests: hematocrit: 23.1 / hemoglobin 7.7 / leukocytes 10,130 (without left deviation) / platelets 638,000 / Negative Cytomegalovirus IgG and IgM and Toxoplasmosis IgG and IgM / VDRL 1:128. Congenital syphilis diagnosis with skin lesions, bone alterations and anemia. Lumbar puncture: glucose 55 / total proteins 26 / VDRL non reagent / 13 leukocytes (8% neutrophils; 84% monomorphonuclear; 8% macrophages) and 160 erythrocytes / negative VDRL and culture. X-ray of other long bones, ophthalmological evaluation and abdominal ultrasound without alterations. Patient was hospitalized for 14 days for treatment with Ceftriaxone 100mg/kg/day, due to the lack of Crystalline Penicillin in the hospital. She is now under outpatient follow-up. Discussion: CS is responsible for high rates of morbidity and mortality. The ongoing increase of cases of this pathology reflects a severe health issue and indicates failures in policies for the prevention of sexually transmitted diseases, with inadequate follow-up of prenatal and maternity protocols.

scholarly journals A Feasibility Study of Kinematic Characteristics on the Upper Body According to the Shooting of Elite Disabled Archery Athletes

2021 ◽  
Vol 18 (6) ◽  
pp. 2962
Author(s):  
Tae-Whan Kim ◽  
Jae-Won Lee ◽  
Seoung-Ki Kang ◽  
Kyu-Yeon Chae ◽  
Sang-Hyup Choi ◽  
...  
Keyword(s):  
The Body ◽  
Lower Limbs ◽  
Upper Body ◽  
Movement Trajectory ◽  
Phase 2 ◽  
Kinematic Characteristics ◽  
Significant Difference ◽  
Athletes With Disabilities ◽  
Body Center ◽  
Time Required

The purpose of this study is to compare and analyze the kinematic characteristics of the upper limb segments during the archery shooting of Paralympic Wheelchair Class archers (ARW2—second wheelchair class—paraplegia or comparable disability) and Paralympic Standing Class archers (ARST—standing archery class—loss of 25 points in the upper limbs or lower limbs), where archers are classified according to their disability grade among elite disabled archers. The participants of this study were selected as seven elite athletes with disabilities by the ARW2 (n = 4) and ARST (n = 3). The analysis variables were (1) the time required for each phase, (2) the angle of inclination of the body center, (3) the change of trajectory of body center, and (4) the change of the movement trajectory of the bow center by phase when performing six shots in total. The ARW2 group (drawing phase; M = 2.228 s, p < 0.05, holding phase; M = 4.414 s, p < 0.05) showed a longer time than the ARST group (drawing phase; M = 0.985 s, holding phase; M = 3.042 s), and the angle of the body did not show a significant difference between the two groups. Additionally, in the direction of the anteroposterior axis in the drawing phase, the change in the movement trajectory of the body center showed a more significant amount of change in the ARW2 group than in the ARST group, and the change in the movement trajectory of the bow center did not show a significant difference between the two groups.

Comparing Shock, Random and Sine Vibration Loads of the Electronic Equipment

2005 ◽  
Author(s):  
Frank Fan Wang
Keyword(s):  
Dynamic Load ◽  
Random Vibration ◽  
Sine Wave ◽  
Electronic Equipment ◽  
Dynamic Loads ◽  
Peak Acceleration ◽  
Maximum Acceleration ◽  
Dynamic Excitations ◽  
Dynamic Damage ◽  
Resonant Point

It is a challenge to correlate different dynamic loads. Often, attempts are made to compare the peak acceleration of sine wave to the root mean square (RMS) acceleration of random vibration and shock. However, peak sine acceleration is the maximum acceleration at one frequency. Random RMS is the square root of the area under a spectral density curve. These are not equivalent. This paper is to discuss a mathematical method to compare different kinds of dynamic damage at the resonant point of the related electronic equipment. The electronic equipment will vibrate at its resonance point when there are dynamic excitations. The alternative excitation at the resonant frequency causes the most damage. This paper uses this theory to develop a method to correlate different dynamic load conditions for electronic equipment. The theory is that if one kind of dynamic load causes the same levels of damaging effects as the other, the levels of vibration can then be related.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

Use of Kinetic and Kinematic Data to Evaluate Load Transfer as a Mechanism for Flexion Relaxation in the Lumbar Spine

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Samuel J. Howarth ◽  
Paul Mastragostino
Keyword(s):  
Lumbar Spine ◽  
Body Mass ◽  
Full Range ◽  
Added Mass ◽  
Erector Spinae ◽  
Lower Limbs ◽  
Upper Body ◽  
Low Back ◽  
Kinematic Data ◽  
Flexion Relaxation

Flexion relaxation (FR) in the low back occurs when load is transferred from the spine's extensor musculature to its passive structures. This study investigated the influence of added upper body mass on low back kinetics and kinematics at the FR onset. Sixteen participants (eight male, eight female) performed standing full forward spine flexion with 0%, 15%, and 30% of their estimated upper body mass added to their shoulders. Electromyographic data were obtained from the lumbar erector spinae. Ground reaction forces and kinematic data from the lower limbs, pelvis, and spine were recorded. Extensor reaction moments (determined using a bottom-up linked segment model) and flexion angles at the FR onset were documented along with the maximum spine flexion. The angle at the FR onset increased significantly with added mass (p < 0.05). Expressing the FR onset angle as a percent of the full range of trunk flexion motion for that condition negated any differences between the added mass conditions. These findings demonstrate that low back kinetics play a role in mediating FR in the lumbar spine.

scholarly journals Evaluation of Induced Settlements of Piled Rafts in the Coupled Static-Dynamic Loads Using Neural Networks and Evolutionary Polynomial Regression

2017 ◽  
Vol 2017 ◽  
pp. 1-23 ◽  
Author(s):  
Ali Ghorbani ◽  
Mostafa Firouzi Niavol
Keyword(s):  
Neural Networks ◽  
Finite Difference ◽  
Polynomial Regression ◽  
Three Dimensional ◽  
Dynamic Loads ◽  
Prototype Model ◽  
Evolutionary Polynomial Regression ◽  
Dimensional Finite Element ◽  
Heavy Loads ◽  
Three Dimensional Finite Element

Coupled Piled Raft Foundations (CPRFs) are broadly applied to share heavy loads of superstructures between piles and rafts and reduce total and differential settlements. Settlements induced by static/coupled static-dynamic loads are one of the main concerns of engineers in designing CPRFs. Evaluation of induced settlements of CPRFs has been commonly carried out using three-dimensional finite element/finite difference modeling or through expensive real-scale/prototype model tests. Since the analyses, especially in the case of coupled static-dynamic loads, are not simply conducted, this paper presents two practical methods to gain the values of settlement. First, different nonlinear finite difference models under different static and coupled static-dynamic loads are developed to calculate exerted settlements. Analyses are performed with respect to different axial loads and pile’s configurations, numbers, lengths, diameters, and spacing for both loading cases. Based on the results of well-validated three-dimensional finite difference modeling, artificial neural networks and evolutionary polynomial regressions are then applied and introduced as capable methods to accurately present both static and coupled static-dynamic settlements. Also, using a sensitivity analysis based on Cosine Amplitude Method, axial load is introduced as the most influential parameter, while the ratio l/d is reported as the least effective parameter on the settlements of CPRFs.

scholarly journals A cross-sectional survey of physical strains among offshore wind farm workers in the German exclusive economic zone

BMJ Open ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. e020157 ◽  
Author(s):  
Marcial Velasco Garrido ◽  
Janika Mette ◽  
Stefanie Mache ◽  
Volker Harth ◽  
Alexandra M Preisser
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Exclusive Economic Zone ◽  
Offshore Wind ◽  
Upper Body ◽  
Offshore Wind Farm ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Heavy Loads ◽  
Under Construction

ObjectivesTo assess the physical strains of employees in the German offshore wind industry, according to job type and phase of the wind farm (under construction or operation).DesignWeb-based cross-sectional survey.SettingOffshore wind farm companies operating within the German exclusive economic zone.ParticipantsMale workers with regular offshore commitments and at least 28 days spent offshore in the past year (n=268).Outcome measuresPhysical strains (eg, climbing, noise, working overhead, with twisted upper body or in confined spaces, vibration, heavy lifting, humidity, odours).ResultsThe most frequently mentioned physical strain was ’climbing’ with 63.8% of the respondents reporting to be always or frequently confronted with climbing and ascending stairs during offshore work. Work as a technician was associated with a greater exposition to noise, vibrations, humidity, cold, heat, chemical substances, lifting/carrying heavy loads, transport of equipment, working in non-ergonomic positions and in cramped spaces, as well as climbing.Indeed, statistical analyses showed that, after adjusting for phase of the wind farm, age, nationality, offshore experience, work schedule and type of shift, compared with non-technicians, working as a technician was associated with more frequently lifting/carrying of heavy loads (OR 2.58, 95% CI 1.58 to 4.23), transport of equipment (OR 2.06 95% CI 1.27 to 3.33), working with a twisted upper body (OR 2.85 95% CI 1.74 to 4.69), working overhead (OR 2.77 95% CI 1.67 to 4.58) and climbing (OR 2.30 95% CI 1.40 to 3.77). Working in wind farms under construction was strongly associated with increased and decreased exposure to humidity (OR 2.32 95% CI 1.38 to 3.92) and poor air quality (OR 0.58 95% CI 0.35 to 0.95), respectively.ConclusionsWorkers on offshore wind farms constitute a heterogeneous group, including a wide variety of occupations. The degree of exposure to detrimental physical strains varies depending on the type of job. Technicians are more exposed to ergonomic challenges than other offshore workers.

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