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    Evaluation of trunk muscle forces and internal loads using kinematics-based modeling

    , Article Proceedings of the IASTED International Conference on Biomedical Engineering, Salzburg, 25 June 2003 through 27 June 2003 ; 2003 , Pages 114-119 ; 0889863539 (ISBN) Shirazi Adl, A ; El-Rich, M ; Parnianpour, M ; Sharif University of Technology
    2003
    Abstract
    Trunk muscle forces and internal loads are computed under simulated standing postures while carrying a load using a nonlinear finite element model of the T1-S1 spine with realistic nonlinear load-displacement properties. A novel kinematics-based algorithm is applied that exploits a set of a priori known spinal sagittal rotations to solve the redundant active-passive system. The loads consist of upper body gravity distributed along the spine plus 200 N held in hands either in front or on sides. Predictions are in good agreement with reported measurements of posture, muscle EMG and intradiscal pressure. Minimal changes in posture (posterior pelvic tilt and lumbar flattening) substantially... 

    A comprehensive evaluation of spine kinematics, kinetics, and trunk muscle activities during fatigue-induced repetitive lifting

    , Article Human Factors ; 2021 ; 00187208 (ISSN) Kazemi, Z ; Mazloumi, A ; Arjmand, N ; Keihani, A ; Karimi, Z ; Ghasemi, M. S ; Kordi, R ; Sharif University of Technology
    SAGE Publications Inc  2021
    Abstract
    Objective: Spine kinematics, kinetics, and trunk muscle activities were evaluated during different stages of a fatigue-induced symmetric lifting task over time. Background: Due to neuromuscular adaptations, postural behaviors of workers during lifting tasks are affected by fatigue. Comprehensive aspects of these adaptations remain to be investigated. Method: Eighteen volunteers repeatedly lifted a box until perceived exhaustion. Body center of mass (CoM), trunk and box kinematics, and feet center of pressure (CoP) were estimated by a motion capture system and force-plate. Electromyographic (EMG) signals of trunk/abdominal muscles were assessed using linear and nonlinear approaches. The L5-S1... 

    A Comparative Study between Available Lifting Tools for Assessment of Risk of Back Injuries

    , M.Sc. Thesis Sharif University of Technology Rajaee, Mohamad Ali (Author) ; Arjmand, Navid (Supervisor)
    Abstract
    Epidemiological studies have identified manual material handling and lifting as risk factors in occupational low back pain (LBP). There are many lifting analysis tools to estimate the risk of injury during a specific lifting task. One for using these tools, needs to know the limitations of each tool and be noticed where a tool cannot be used. The purpose of this study is to compare different biomechanical models of lumbar spine and find out their characteristics.Five models are chosen for this study which are: the University of Michigan’s Static Strength Prediction Program ( ) software, the revised Hand-Calculation Back Compressive Force (HCBCF) equation, the simple polynomial equation of... 

    Biomechanical Modeling of Human Eye in Blunt Impact: A Finite Element Study

    , M.Sc. Thesis Sharif University of Technology Rahmannia, Saeed (Author) ; Ahmadian, Mohammad taghi (Supervisor) ; Fallah Rajabzadeh, Famida (Co-Advisor)
    Abstract
    Nowadays, Eye injuries caused by blunt impacts are considered among the major causes of blindness and vision problems; therefore, studying the existence of possible damages can be quite useful and effective. One of the quickest and most suitable methods in identifying damage parameters is finite-element modeling of the human eye. In this regard, in the current study, first a geometrical design was created by incorporating CT-Scan images of the eye into Mimics and later Solid works software. Afterwards, the most suitable mechanical properties for the constituents of the eye were extracted from the literature. The mechanical properties of vitreous and Sclera were obtained by experimental... 

    Sagittal Range of Motion of the Thoracic Spine Using Inertial Tracking Device and Effect of Measurement Errors on Model Predictions

    , M.Sc. Thesis Sharif University of Technology Hajibozorgi, Mahdieh (Author) ; Arjmand, Navid (Supervisor)
    Abstract
    Range of motion (ROM) of the thoracic spine has implications in patient discrimination for diagnostic purposes and in biomechanical models for predictions of spinal loads. Few previous studies have reported quite different thoracic ROMs. Total (T1-T12), lower (T5-T12) and upper (T1-T5) thoracic, lumbar (T12-S1), pelvis, and entire trunk (T1) ROMs were measured using an inertial tracking device as asymptomatic subjects flexed forward from their neutral upright position to full forward flexion. Correlations between body height and the ROMs were conducted. Effect of measurement errors of the trunk flexion (T1) on the model-predicted spinal loads was investigated. Mean of peak voluntary total... 

    A Detailed Finite Element Model of the Lumbar Spine under Muscle Forces

    , M.Sc. Thesis Sharif University of Technology Asadi, Hamed (Author) ; Arjmand, Navid (Supervisor)
    Abstract
    Etiological studies proves the fact that Low Back Pain (LBP) is one of the most expensive and prevalent desease all over the world. This fact illustrates the reqiurment of the special effort in ordet to reducing the pain due to this problem. Finite element modeling of human spine is one the suitable methods to simulate the behavior of human spine in different loading conditions. These conditions could be different daily occupational tasks. There is two general viewpoint toward finite element modeling of human spine. The fisrt method focuses on the detailed geometry and mechanical properties of spine, while the other complexities such as detailed muscle forces are overlooked. The latter... 

    Effect of Iatrogenic Muscle Injuries on Spine Biomechanics During Posterior Lumbar Surgeries Using a Biomechanical Model for Design of Rehabilitation Exercises

    , M.Sc. Thesis Sharif University of Technology Jamshidnezhad, Saman (Author) ; Arjmand, Navid (Supervisor)
    Abstract
    Posterior lumbar surgery is often associated with extensive injuries to back muscles. In this thesis, the effect of such iatrogenic injuries in some patients was examined. For this purpose, the CSA of back muscles in 6 patients were measured using MR scan. To examine any natural change in CSAs of healthy people or instrument errors, same measurement were carried out on 10 healthy volunteers. In addition, a detailed anatomical model of an intact human spine was developed. With the aim of experimental studies and intact model, the post-operative model of patients was also developed. These two models were used to quantizing the change in activity of back muscles during some symmetric, normal... 

    Effects of Low Back Pain and Posterior Lumbar Surgery on Pattern of Muscle Activities, Trunk Strength and Spinal Stability

    , M.Sc. Thesis Sharif University of Technology Ghiasi, Mohammad Sadegh (Author) ; Farahmand, Farzam (Supervisor) ; Arjmand, Navid (Co-Advisor)
    Abstract
    80% of people in all over the world, experience Low Back Pain (LBP) once in their lives. LBP leads to dysfunction of spine. About 25% of LBP relates to the intervertebral disks which in the critical cases, a Posterior Lumbar Surgery (PLS) on the one or more lumbar disks should be done. Due to the some procedure such as retracting, cutting or denervation of muscles, PLS can hurt trunk muscles and spine. Thus, investigation of LBP and postoperative complications of PLS can help us in recognition of causes of LBP and PLS complications and modification of PLS approaches. The objective of this research was investigation of effects of LBP and PLS on the biomechanical function of spine. Pattern of... 

    Monte Carlo simulation of spine geometry from T12 to sacrum in males

    , Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 1 , 2010 , Pages 813-820 ; 9780791849156 (ISBN) Komeilizadeh, K ; Asghari, M ; Junno, J. A ; Parnianpour, M ; Sharif University of Technology
    2010
    Abstract
    In biomechanical modeling of spine, the prediction of spinal loading during occupational activities is crucial in assessment of the risk of low back pain and injury of spine. Current biomechanical models are based on the average data. Hence, they are unable to predict the effects of the observed natural anatomical variations on muscles moment arms and lines of action, while these variations ultimately influence the required muscular forces for balancing the external moments of any given task. In this work, a methodology based on the Monte Carlo technique has been developed to simulate spine geometry from T12 to S1 vertebrae for males. The lordosis of the assembled spine ranged between 21° to... 

    Biomechanical Modeling of Human Eye in Car Airbag Blunt Impacts During Accident: an Empirical Test and Finite Element Study

    , M.Sc. Thesis Sharif University of Technology Shirzadi, Hooman (Author) ; Zohour, Hassan (Supervisor)
    Abstract
    Eye and vision are the most important tools and the perceptual sense of human. This important vital member is one of the most vulnerable organs of human body. For example in the United States 1.9 million eye surgery are being done yearly which include 9 thousand globe rupture and 30 thousand blindness due to impacts on the eye. Eye traumas could have occurred as mechanical, radiation, thermal, chemical, etc. among these, the damages related to the airbag impact which is subset of mechanical damages, take a significant percentage. Presenting a model of human eye in car airbag blunt impacts during accident could be effective for receiving helpful information from damage of the internal parts... 

    Design Of a 3 DOF Robotic Exoskeleton With EMG Based Controller fFor Human Shoulder Joint

    , M.Sc. Thesis Sharif University of Technology Soleymani, Mohammad Ali (Author) ; Zohoor, Hassan (Supervisor)
    Abstract
    Most elderly and physically disabled people suffer from lack of functionality and dexterity in their elbow or wrist. These disabilities are due to the damages mostly caused by sport surgery, spinal surgery, or stroke. Therefore, design of an assistive exoskeleton robot for upper limb movements seems necessary. The purpose of this study is to design, fabricate and deliver a control algorithm for an assistive wearable robot. The robot has five degrees of freedom in order to help the flexion/extension and abduction/adduction shoulder. Dynamic and kinematic model of elbow, forearm, and wrist is developed to determine the amounts of torques which are required in the joint actuators mounted on the... 

    Prediction and Compensation of Intraoperative Brain Shift Using Biomechanical Modeling

    , M.Sc. Thesis Sharif University of Technology Pasandideh Pour, Javad (Author) ; Farahmand, Farzam (Supervisor)
    Abstract
    The human brain is the most sensitive and important human organ and surgery must be done with high precision and without risk. During surgery, brain tissue deform continuously due to gravity, out of the cerebrospinal fluid and the changing pressure of the cerebrospinal fluid and the surgical maneuvers. Because the surgeon has no direct view on brain internal, the ways to solve this problem is to pay attention. This method makes it possible to the surgeon see in the brain and the brain tissue deformation. This thesis method is based on biomechanical modeling. After forming finite element model from the pre-operative MRI, brain surface and volume datasets during surgery as a load, apply to the... 

    Development of a Anatomical Finite Element Model for Ankle Sprain and Rehabilitation Exercise Simulation and Numerical Analysis of Tension in Ligament

    , M.Sc. Thesis Sharif University of Technology (Author) ; Firoozbakhsh, Keikhosrow (Supervisor) ; Farahmand, Farzam (Co-Advisor) ; Narimani, Roya (Co-Advisor)
    Abstract
    Foot related problems or diseases such as plan foot pain, diabetic foot, arthritic foot, pathological flatfoot, ankle sprain, bone fracture or other sports related injuries have been costing a significant amount of medical expenditure. Abnormal loading patterns and high pressure on the foot as well as improper or ill-fitting footwear are thought to be one major mechanical cause of foot problems. Most ankle sprains respond favorably to nonsurgical treatment, such as those offered by physical therapists, doctors of chiropractic, and rehabilitation specialists. A comprehensive history and examination aid in diagnosing the severity and type of ankle sprain. Based on the diagnosis and an... 

    Evaluation of 1991 NIOSH Lifting Equation in Controlling the Biomechanical Loads of the Human Spine

    , M.Sc. Thesis Sharif University of Technology Lesani, Ali (Author) ; Arjmand, Navid (Supervisor)
    Abstract
    The 1991 NIOSH Lifting Equation (NLE) is widely used to assess risk of injury to the spine by providing estimates of the recommended weight limit (RWL) in hands. The present study uses two biomechanical models of the spine to verify whether the RWL generates L5-S1 loads within the limits (e.g., 3400 N for compression recommended by NIOSH and 1000 N for shear recommended in some studies).Severallifting activities are simulated here to evaluate the RWL by the NLE and the L5-S1 loads by the models. In lifting activities involving moderate to large forward trunk flexion, the estimated RWL generates L5-S1 spine loads exceeding the recommended limits. The NIOSH vertical multiplier is the likely... 

    Comparison of Stabilization Exercise and General Exercise on the Spinal Stability of Non-specific Low Back Pain Patients Using an EMG-based Biomechanical Model

    , M.Sc. Thesis Sharif University of Technology Ghezelbash, Farshid (Author) ; Arjmand, Navid (Supervisor) ; Parnianpour, Mohamad (Supervisor)
    Abstract
    Low back pain is one of the musculoskeletal diseases which is an important issue for general health of society in both quality of life and costs. Most of the clinical instructions employ exercise as a clinical treatment in order to cure chronic low back pain. General and core stability exercises are of common prevalence, however, there are disputes about the effectiveness of these exercises in the literature. The aim of this study is to answer the question whether stabilizer exercise can significantly alter the stability of vertebral column in comparison with general exercises. Hence, experiments have been designed and conducted. The participants have been divided to two group. Within six... 

    Effect of Obesity on Spinal Loads during Various Activities: A Combined in Vivo-Modeling Approach

    , M.Sc. Thesis Sharif University of Technology Kazemi, Hossein (Author) ; Arjmand, Navid (Supervisor) ; Parnianpour, Mohammad (Supervisor)
    Abstract
    Obesity is a worldwide growing health challenge affecting ~30% of the world's population. Increased rate of disc degeneration and herniation, low back pain and surgery has been reported in obese individuals. Although obesity-related low back diseases have multifactorial etiology, presumably greater mechanical loads on the spine of heavier individuals during their daily activities may be considered as a risk factor. Likely larger trunk muscle sizes, disc sizes and thus passive stiffness in heavier individuals may however partly or fully offset the effect of their additional body weight on the spinal loads. In absence of in vivo approaches, the present study aims to construct subject-specific... 

    Effect of Obesity on Spinal Loads during Various Activities: A Combined in Vivo-Modeling Approach

    , M.Sc. Thesis Sharif University of Technology Akhavanfar, Mohammad Hossein (Author) ; Arjmand, Navid (Supervisor)
    Abstract
    Obesity is a worldwide growing health challenge affecting ~30% of the world's population. Increased rate of disc degeneration and herniation, low back pain and surgery has been reported in obese individuals. Although obesity-related low back diseases have multifactorial etiology, presumably greater mechanical loads on the spine of heavier individuals during their daily activities may be considered as a risk factor. Likely larger trunk muscle sizes, disc sizes and thus passive stiffness in heavier individuals may however partly or fully offset the effect of their additional body weight on the spinal loads. In absence of in vivo approaches, the present study aims to construct subject-specific... 

    Biomechanical Modeling of Flexible-bar and Investigating of Muscle Forces and Compression Forces on Discs in Lumbar Region During of Rehabilitation Exercises

    , M.Sc. Thesis Sharif University of Technology Abdollahi, Masoud (Author) ; Parnianpour, Mohammad (Supervisor) ; Asghari, Mohsen (Supervisor)
    Abstract
    A single-degree-of-freedom model is considered for flexible exercise bars based on the lumped-element approach. By considering the side segment of a flexible exercise bar as a cantilever beam with an equivalent mass at the free end, its free-vibration response and forced one under excitation of the grip of the flexible bar is written parametrically. Some experiments are performed on a specific flexible bar to obtain numerical values for the parameters in the model to have it quantitatively known. In the next step, simulation of the model results in the response of the flexible bar under a considered excitation. The response is imported into a multi-segment musculoskeletal software, AnyBody,... 

    Real-time Tracking of the Lumbar Spine with Surgical Navigation System and Biomechanical Modeling

    , M.Sc. Thesis Sharif University of Technology Sarrami, Saman (Author) ; Behzadipour, Saeed (Supervisor) ; Farahmand, Farzam (Co-Advisor)
    Abstract
    One of the most important parts of the human’s body is spine. Its anatomy is very complex and has many degrees off freedom. Many kinds of diseases might occur for this part. One of the ways of treatment for this part is surgery that it has different types. In the past decades the surgeries have been done very simple without the help of computers or robots. In other words the surgeon did the surgery with no use of lateral tools. For this reason the error in those surgeries was high. Doing a surgery on the spine level needs a special attention. As the technology improved very much in the last 2 decades the amount of errors has been reduced and various kinds of techniques came in the scene to... 

    Optimization of a passenger occupied seat with suspension system exposed to vertical vibrations using genetic algorithms

    , Article Journal of Vibroengineering ; Volume 15, Issue 2 , 2013 , Pages 979-991 ; 13928716 (ISSN) Afkar, A ; Javanshir, I ; Ahmadian, M. T ; Ahmadi, H ; Sharif University of Technology
    2013
    Abstract
    This paper presents a biomechanical model with seven degrees of freedom as a seated human exposed to vertical vibration. Experimental data is used to find the stiffness and damping parameters of the model. The data includes values of seat to head transmissibility, driving point mechanical impedance and apparent mass. The multi-objective function is used to obtain theoretical results similar to three different experimental cases. The unknown coefficients are calculated by a genetic algorithm. Improved results, in comparison with previous models, are achieved from the presented model. Next, this modified model is assembled on a quarter car and parameters of the cushion and the suspension...