Search for: biomechanics
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    Design and development of a hand robotic rehabilitation device for post stroke patients

    , Article Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference ; 2009 , Pages 5026-5029 ; 1557170X (ISSN) Rashedi, E ; Mirbagheri, A ; Taheri, B ; Farahmand, F ; Vossoughi, G. R ; Parnianpour, M ; Sharif University of Technology
    Robot-mediated rehabilitation is a rapidly advancing discipline that seeks to develop improved treatment procedures using new technologies, e.g., robotics, coupled with modern theories in neuroscience and rehabilitation. A robotic device was designed and developed for rehabilitation of upper limbs of post stroke patients. A novel force feedback bimanual working mode provided real-time dynamic sensation of the paretic hand. Results of the preliminary clinical tests revealed a quantitative evaluation of the patient's level of paresis and disability  

    Lower extremity kinematic coupling during single and double leg landing and gait in female junior athletes with dynamic knee valgus

    , Article BMC Sports Science, Medicine and Rehabilitation ; Volume 13, Issue 1 , 2021 ; 20521847 (ISSN) Dadfar, M ; Sheikhhoseini, R ; Jafarian, M ; Esmaeili, A ; Sharif University of Technology
    BioMed Central Ltd  2021
    Background: Dynamic knee valgus (DKV) is a common lower extremity movement disorder among females. This study aimed to investigate kinematic couplings between lower extremity joints in female junior athletes with DKV during single and double-leg landing and gait. Methods: Twenty-six physically active female junior athletes (10–14 years old) with DKV were recruited. Kinematic couplings between rearfoot, tibia, knee, and hip were extracted using eight Vicon motion capture cameras and two force plates. Zero-lag cross-correlation coefficient and vector coding were used to calculate kinematic couplings between joints during physical tasks. Paired t-test and Wilcoxon tests were run to find... 

    Simulation of manual materials handling: Biomechanial assessment under different lifting conditions

    , Article Technology and Health Care ; Volume 13, Issue 1 , 2005 , Pages 57-66 ; 09287329 (ISSN) Gündogdu, Ö ; Anderson, K. S ; Parnianpour, M ; Sharif University of Technology
    IOS Press  2005
    Manual material handling (MMH) tasks were evaluated and compared under different lifting conditions. For the theoretical evaluations, a two-dimensional sagittally symmetric human-body model was established to compute the moment and joint load time histories for MMH tasks for a variety of different lift specifications and constraints such as lifting durations, loads, and modes. Nonlinear control techniques and genetic algorithms were utilized in the optimizations to explore optimal lifting patterns. Since the kinetic measures such as joint moments are vital metrics in the assessment of the likelihood of injury, the simulation results obtained may be compared using these metrics for each lift... 

    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
    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... 

    Effects of an exercise therapy targeting knee kinetics on pain, function, and gait kinetics in patients with knee osteoarthritis: A randomized clinical trial

    , Article Adapted Physical Activity Quarterly ; Volume 38, Issue 3 , 2021 , Pages 377-395 ; 07365829 (ISSN) Bokaeian, H. R ; Esfandiarpour, F ; Zahednejad, S ; Kouhzad Mohammadi, H ; Farahmand, F ; Sharif University of Technology
    Human Kinetics Publishers Inc  2021
    In this study, the effects of an exercise therapy comprising yoga exercises and medial-thrust gait (YogaMT) on lower-extremity kinetics, pain, and function in patients with medial knee osteoarthritis were investigated. Fifty-nine patients were randomly allocated to three treatment groups: (a) the YogaMT group practiced yoga exercises and medial thrust gait, (b) the knee-strengthening group performed quadriceps-and hamstring-strengthening exercises, and (c) the treadmill walking group practiced normal treadmill walking in 12 supervised sessions. The adduction and flexion moments of the hip, knee, and ankle; pain intensity; and 2-min walking test were assessed before and after treatment and at... 

    Biomechanical assessment of the niosh lifting equation in asymmetric load-handling activities using a detailed musculoskeletal model

    , Article Human Factors ; Volume 61, Issue 2 , 2019 , Pages 191-202 ; 00187208 (ISSN) Behjati, M ; Arjmand, N ; Sharif University of Technology
    SAGE Publications Inc  2019
    Objective: To assess adequacy of the National Institute for Occupational Safety and Health (NIOSH) Lifting Equation (NLE) in controlling lumbar spine loads below their recommended action limits during asymmetric load-handling activities using a detailed musculoskeletal model, that is, the AnyBody Modeling System. Background: The NIOSH committee employed simplistic biomechanical models for the calculation of the spine compressive loads with no estimates of the shear loads. It is therefore unknown whether the NLE would adequately control lumbar compression and shear loads below their recommended action limits during asymmetric load-handling activities. Method: Twenty-four static stoop lifting... 

    Effects of human stature and muscle strength on the standing strategies: A computational biomechanical study

    , Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 234, Issue 7 , 2020 , Pages 674-685 Ashtiani, M. N ; Azghani, M. R ; Parnianpour, M ; Khalaf, K ; Sharif University of Technology
    SAGE Publications Ltd  2020
    It has been hypothesized that the muscular efforts exerted during standing may be altered by changes in personal factors, such as the body stature and muscular strength. The goal of this work was to assess the contribution of leg muscles using a biomechanical model in different physical conditions and various initial postures. An optimized inverse dynamics model was employed to find the maximum muscular effort in 23,040 postures. The simulation results showed that mid-range knee flexion could help the healthy and strong individuals maintain balance, but those with weaker muscle strength required more knee flexion. Individuals of weak muscular constitution as well as those with tall stature... 

    The biomechanical response of the lower cervical spine post laminectomy: geometrically-parametric patient-specific finite element analyses

    , Article Journal of Medical and Biological Engineering ; Volume 41 , 29 October , 2020 , Pages 59-70 Nikkhoo, M ; Cheng, C. H ; Wang, J. L ; Niu, C. C ; Parnianpour, M ; Khalaf, K ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2020
    Purpose: This study aimed to investigate the biomechanical impact of laminectomy on cervical intersegmental motion and load sharing using a parametric patient-specific finite element (FE) model towards providing clinicians with a viable quantitative tool for informed decision-making and improved surgical planning. Methods: Ten subject-specific nonlinear osteo-ligamentous cervical spine (C3–C7) FE models were developed using X-ray image-based algorithms. The models were used to evaluate the effect of laminectomy on lower cervical spine biomechanics for two-level (C3–C4) and three-level (C3–C5) laminectomy procedures. Results: The average cervical spine ranges of motion (ROM) for the pre-op... 

    Quantitative determination of optical trapping strength and viscoelastic moduli inside living cells

    , Article Physical Biology ; Volume 10, Issue 4 , 2013 ; 14783967 (ISSN) Mas, J ; Richardson, A. C ; Reihani, S. N. S ; Oddershede, L. B ; Berg Sorensen, K ; Sharif University of Technology
    With the success of in vitro single-molecule force measurements obtained in recent years, the next step is to perform quantitative force measurements inside a living cell. Optical traps have proven excellent tools for manipulation, also in vivo, where they can be essentially non-invasive under correct wavelength and exposure conditions. It is a pre-requisite for in vivo quantitative force measurements that a precise and reliable force calibration of the tweezers is performed. There are well-established calibration protocols in purely viscous environments; however, as the cellular cytoplasm is viscoelastic, it would be incorrect to use a calibration procedure relying on a viscous environment.... 

    A surface registration technique for estimation of 3-D kinematics of joints

    , Article Studies in Health Technology and Informatics, 19 January 2009 through 22 January 2009 ; Volume 142 , 2009 , Pages 204-206 ; 09269630 (ISSN) ; 9781586039646 (ISBN) Mostafavi, K ; Jafari, A ; Farahmand, F ; Sharif University of Technology
    This study proposes a new technique for registration of complicated freeform surfaces. The relationship between the initial and transferred location/orientation of a points cloud is formulated and then generalized within the framework of the influence surface modeling approach using least squares method. Results of case studies for estimation of the transformation matrix of articular surface of the knee joint in two scenes of MR images indicated high accuracies of ±1 mm and ±1 degree  

    An investigation on human vibration analysis using image processing method

    , Article DETC2005: ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Long Beach, CA, 24 September 2005 through 28 September 2005 ; Volume 1 C , 2005 , Pages 2607-2612 ; 0791847381 (ISBN); 9780791847381 (ISBN) Hoviattalab, M ; Narimani, R ; Mirbagheri, A ; Sharif University of Technology
    American Society of Mechanical Engineers  2005
    Vibration measurement is an important tool in many research fields; there are several methods for measuring vibration of a system. In conventional methods accelerometers are fixed to the body, so there is a systemic error due to fixing an external object to the body surface that interferes with the true vibration of the body. We have proposed image processing as a new method to record and determine the frequency response of human body. This method provides vibration measuring without using contacting sensors. Moreover the main advantage is its lower noise sensitivity in comparison to accelerometers. Further more another important point is the fact that all devices used in our developed... 

    The effect of chronic low back pain on trunk accuracy in a multidirectional isometric tracking task

    , Article Spine ; Vol. 39, Issue. 26 , 2014 , pp. E1608-E1615 ; ISSN: 1362-2436 Hadizadeh, M ; Mousavi, S. J ; Sedaghatnejad, E ; Talebian, S ; Parnianpour, M ; Sharif University of Technology
    Study Design. A cross-sectional study to quantify trunk motor control during multidirectional isometric tracking tasks.Objective. To investigate the effect of chronic low back pain (LBP) on trunk neuromuscular performance while participants performed isometric exertions of trunk muscles to track targets in different angles with various magnitudes.Summary of Background Data. Tracking tasks especially in multidirectional activities are among the common research methods to quantify human motor control in different conditions. However, little information is available on trunk motor control during these tasks. There is no study investigating trunk accuracy during multidirectional isometric... 

    Biomechanical comparison between bashti bone plug technique and biodegradable screw for fixation of grafts in ligament surgery

    , Article Archives of Bone and Joint Surgery ; Volume 3, Issue 1 , January , 2015 , Pages 29-34 ; 23454644 (ISSN) Bashti, K ; Tahmasebi, M. N ; Kaseb, H ; Farahmand, F ; Akbar, M ; Mobini, A ; Sharif University of Technology
    Mashhad University of Medical Sciences  2015
    Background: Ligament reconstruction is a common procedure in orthopedic surgery. Although several popular techniques are currently in use, new methods are proposed for secure fixation of the tendon graft into the bone tunnel. Purposes: We sought to introduce our new technique of Bashti bone plug for fixation of soft tissue graft in anterior cruciate ligament (ACL) reconstruction and to compare its biomechanical features with conventional absorbable interference screw technique in a bovine model. Methods: Twenty pairs of bovine knees were harvested after death. Soft tissue was removed and the Achilles tendon was harvested to be used as an ACL graft. It was secured into the bone tunnel on the... 

    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
    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... 

    New image-based system for vibration measurment, specially developed for forced human vibration analysis

    , Article 2004 ASME International Mechanical Engineering Congress and Exposition, IMECE, Anaheim, CA, 13 November 2004 through 19 November 2004 ; 2004 , Pages 203-204 ; 03609960 (ISSN) Hoviattalab, M ; Yadolahi, A ; Narimani, R ; Abadpour, A ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2004
    The human being in the environments of modern technology has to endure stresses of many and varied kinds of vibrations. Measuring vibration is an important tool in rehabilitation and biomechanical fields of research. We have proposed image processing as a new method to record and determine the frequency response of human body. The subjects were exposed to whole body periodical vibration while standing on a shaking table. Two digital camcorders were used to capture the motion of colored pencil-dot markers on the skin of human body (forehead) and on the edge of the shaking table. After color spotting each frame, the binary image results were processed using new circle factor criteria proposed... 

    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)
    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... 

    Accuracy of the Microsoft Kinect in Measurement of the Trunk Kinematics for the Analyze of Load in Musculoskeletal Models

    , M.Sc. Thesis Sharif University of Technology Asadi, Fatemeh (Author) ; Arjmand, Navid (Supervisor)
    Low back pain is one of the most prevalent musculoskeletal injuries in occupational activities. In order to reduce or prevent it, it is necessary to estimate the mechanical loads of body joints. Direct measurement of spinal loads is invasive and costly. Therefore, musculoskeletal modeling is a convenient tool in estimation of joints and muscles loads that often uses kinematics information as input.Marker-based motion capture systems are one of the most common ways for the estimation of body kinematics. Unfortunately, they are time consuming and expensive. Thus being marker-free and low-cost, Microsoft Kinect is a suitable alternative. Recent studies often have investigated accuracy of... 

    Parallel in-vitro and in-vivo techniques for optimizing cellular microenvironments by implementing biochemical, biomechanical and electromagnetic stimulations

    , Article Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS ; 2012 , Pages 1397-1400 ; 1557170X (ISSN) ; 9781424441198 (ISBN) Shamloo, A ; Heibatollahi, M ; Ghafar Zadeh, E
    Development of novel engineering techniques that can promote new clinical treatments requires implementing multidisciplinary in-vitro and in-vivo approaches. In this study, we have implemented microfluidic devices and in-vivorat model to study the mechanism of neural stem cell migration and differentiation.These studies can result in the treatment of damages to the neuronal system. In this research, we have shown that by applying appropriate ranges of biochemical and biomechanical factors as well as by exposing the cells to electromagnetic fields, it is possible to improve viability, proliferation, directional migration and differentiation of neural stem cells. The results of this study can... 

    Design of an optimum torque actuator for augmenting lower extremity exoskeletons in biomechanical framework

    , Article 2011 IEEE International Conference on Robotics and Biomimetics, ROBIO 2011 ; 2011 , Pages 1979-1983 ; 9781457721373 (ISBN) Safavi, S ; Ghafari, A. S ; Meghdari, A ; Sharif University of Technology
    This research presents virtual prototyping and performance evaluation of a series elastic torque actuator developed for augmenting lower extremity exoskeletal systems employing biomechanical framework. For this purpose, experimental kinematical data of the lower extremity were collected for walking and backpack load carrying. Forward dynamics simulation of the movements under investigation is performed in a biomechanical framework consisting of a musculoskeletal model with ten degrees-of-freedom actuated by eighteen Hill-type musculotendon actuators per leg to perform the muscle functional analysis. Muscle torque analysis results employed for optimal design and selection of components in the... 

    Stiffness of knee-spanning external fixation systems for traumatic knee dislocations: A biomechanical study

    , Article Journal of Orthopaedic Trauma ; Volume 24, Issue 11 , Nov , 2010 , Pages 693-696 ; 08905339 (ISSN) Mercer, D ; Firoozbakhsh, K ; Prevost, M ; Mulkey, P ; Decoster, T. A ; Schenck, R ; Sharif University of Technology
    Objective: The purpose of this study was to compare the relative stiffness of four common external fixation (XF) configurations used to span and stabilize the knee after knee dislocation. Methods: Synthetic composite femora and tibiae connected with cords were used to simulate a knee. Four configurations of external fixation were tested: anterior femoral pins with monotube (XF1), anterolateral femoral pins with monotube (XF2), anterolateral femoral pins with two connecting rods (XF3), and hinged ring fixator (XF4). Six specimens of each configuration were loaded nondestructively in varus/valgus, anterior-to- posterior shear, flexion/extension, axial compression, internal/external torsion,...