Biomechanics Commons^™

Accurate Determination And Application Of Local Strain For Studying Tissues With Gradients In Mechanical Properties, John Boyle

McKelvey School of Engineering Theses & Dissertations

Determination of the mechanical behavior of materials requires an understanding of deformation during loading. While this is traditionally accomplished in engineering by examining a force displacement curve for a whole sample, these techniques implicitly ignore local geometric complexities and local material inhomogeneities commonly found in biologic tissues. Techniques such as normalized cross correlation have been classically applied to address this issue and resolve deformation at the local level; however, these techniques have proven unreliable when deformations become large, if the sample undergoes a rotation, and/or if strain fields become incompatible (e.g. at or near failure).

Presented here is a toolbox …

Characterizing Anisotropy In Fibrous Soft Materials By Mr Elastography Of Slow And Fast Shear Waves, John Larson Schmidt

McKelvey School of Engineering Theses & Dissertations

The general objective of this work was to develop experimental methods based on magnetic resonance elastography (MRE) to characterize fibrous soft materials. Mathematical models of tissue biomechanics capable of predicting injury, such as traumatic brain injury (TBI), are of great interest and potential. However, the accuracy of predictions from such models depends on accuracy of the underlying material parameters. This dissertation describes work toward three aims. First, experimental methods were designed to characterize fibrous materials based on a transversely isotropic material model. Second, these methods are applied to characterize the anisotropic properties of white matter brain tissue ex vivo. Third, …

Mechanics Of The Developing Brain: From Smooth-Walled Tube To The Folded Cortex, Kara Ellspermann Garcia

McKelvey School of Engineering Theses & Dissertations

Over the course of human development, the brain undergoes dramatic physical changes to achieve its final, convoluted shape. However, the forces underlying every cinch, bulge, and fold remain poorly understood. This doctoral research focuses on the mechanical processes responsible for early (embryonic) and late (preterm) brain development.

First, we examine early brain development in the chicken embryo, which is similar to human at these stages. Research has primarily focused on molecular signals to describe morphogenesis, but mechanical analysis can also provide important insights. Using a combination of experiments and finite element modeling, we find that actomyosin contraction is responsible for …

Effects Of Direction Time Constraints And Walking Speed On Turn Strategies And Gait Adaptations In Healthy Older And Young Adults, Dennis Torre

Seton Hall University Dissertations and Theses (ETDs)

Hip fractures can be life-threatening, debilitating, and costly. The odds for hip fracture increases from impact of sideways falls. While turning has been strongly associated with hip fracture & sideways falls, the distinction between the risks for walking-turns as opposed to low-velocity in-place turning is not clear. The present study sought to fill a gap as previous research had not compared walking-turn performance in young & healthy older adults at low-fall risk within the same study and response-conditions of speed interacting with direction-cue time constraints. Spatial-temporal variables representative of AP braking/propulsion (i.e. stride-length & speed) & ML stability (left/right H-H …

Rehabilitating Asymmetric Gait Using Asymmetry, Tyagi Ramakrishnan

USF Tampa Graduate Theses and Dissertations

Human gait is a complex process that involves the coordination of the central nervous and muscular systems. A disruption to the either system results in the impairment of a person’s ability to walk. Impairments can be caused by neurological disorders such as stroke and physical conditions like amputation. There is not a standardized method to quantitatively assess the gait asymmetry of affected subjects. The purpose of this research is to understand the fundamental aspects of asymmetrical effects on the human body and improve rehabilitation techniques and devices. This research takes an interdisciplinary approach to address the limitations with current rehabilitation …

Physical Activity And Age-Related Mechanical Risk Factors For Knee Osteoarthritis, Jocelyn F. Hafer

Doctoral Dissertations

Knee osteoarthritis is an age-related disease which will affect nearly 50% of individuals in their lifetime. Because there are currently no treatments to substantially slow the progression of this disease, it is important to identify mechanisms to reduce the risk of osteoarthritis initiation. Osteoarthritis is a disease which is at least partially mediated by mechanical factors which may result from age-related changes in gait. The extent to which habitual physical activity can modify the impact of age on gait, knee mechanics, and thus cartilage loading is unknown. The aim of this dissertation was to examine the effects of age and …

Quantifying Gait Adaptability: Fractality, Complexity, And Stability During Asymmetric Walking, Scott W. Ducharme

Doctoral Dissertations

Successful walking necessitates modifying locomotor patterns when encountering organism, task, or environmental constraints. The structure of stride-to-stride variance (fractal dynamics) may represent the adaptive capacity of the locomotor system. To date, however, fractal dynamics have been assessed during unperturbed walking. Quantifying gait adaptability requires tasks that compel locomotor patterns to adapt. The purpose of this dissertation was to determine the potential relationship between fractal dynamics and gait adaptability. The studies presented herein represent a necessary endeavor to incorporate both an analysis of gait fractal dynamics and a task requiring adaptation of locomotor patterns. The adaptation task involved walking asymmetrically on …

Mechanobiology Of Epithelial Clusters In Ecms Of Diverse Mechanical Properties, Samila Nasrollahi

McKelvey School of Engineering Theses & Dissertations

Cell clusters reside in complex extracellular matrices (ECMs) of varying mechanical properties. Epithelial cells sense and translate the mechanical cues presented by the surrounding ECM into biochemical signals through a process called ‘mechanotransduction’, which controls fundamental aspects of disease and development. During the course of metastasis, mechanical changes in the tumor microenvironment can lead to declustering of epithelial cells through a process called epithelial-to-mesenchymal transition (EMT). Throughout different steps of metastasis, escaped epithelial clusters encounter heterogeneous tissues of varying mechanical properties that ultimately influence their behavior in distant locations within the body. This dissertation investigates the mechanobiology of epithelial clusters …

The Influence Of Crossfit Training On Running Mechanics, Sophia D. Bradley

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction

40 million Americans run regularly.1 Contrary to many runner’s beliefs, increased strength may be beneficial while not adding body mass. An increase in strength in specific muscles may improve running gait and performance. 9,6 Strength training may also play an important role in preventing common overuse injuries in running 11,12 Depending on the style of strength training, it may also have an enhanced benefit on running economy.4,16

Participation in CrossFit is also widely popular, with an increase in participation of 923% in the past ten years.2 CrossFit is a type of strength training in which most movements performed utilize …

An Array Of Circular Dielectrophoresis Traps To Separate And Charaterize Individual Microparticles From Population, Hwangjae Lee

Theses and Dissertations

Dielectrophoretic traps have been broadly studied in light of their many advantages of high controllability, ease of operation, and high efficiency. In the previous studies, however, it was challenging to count captured particles or required work to capture particles. In the thesis, an array of circular dielectrophoresis (DEP) traps was developed and tested to manipulate population of microparticles in single particle level. The circular DEP traps enable more precise control of the force field than conventionally used interdigitated electrodes due to its omnidirectional and symmetric properties. The location of the captured microparticle inside the trap was confirmed by both of …

Analysis Of Human Movement Patterns During Endurance Running, Joshua Paul Bailey

UNLV Theses, Dissertations, Professional Papers, and Capstones

Endurance running and participation in racing events has flourished over the last decade. Recreational runners enter the training period for an upcoming race at differing levels of fitness and training. As individuals sign-up for the race, they typically follow the commitment with an increase in training load. The increases in training load are accomplished through a combination of increasing mileage, or duration of running, and running intensity through increase velocity. These increases are theoretically being applied in a progressive overload principle, where the musculoskeletal system has time to adapt to the breakdown provided from the previous training session. Progressive overload …

Optimization Of Prosthetic Hands: Utilizing Modularity To Improve Grip Force, Grasp, And Versatility, Jordan William Harris

UNLV Theses, Dissertations, Professional Papers, and Capstones

It has been demonstrated that although many varieties of upper limb prosthetics exist, commercially available prosthetics are outdated and unsatisfactory. Ineffectiveness and limitations have led to some prosthesis wearers having to own multiple devices, whereas others have given up on them entirely. Even though ample research has been conducted to design and test new hand designs, the industry appears to rest in an overall stagnated state.

It was proposed here, that one problem with prosthetic research is an excess of variables involved in testing, and therefore the improper application of the scientific method. It seems that each time a research …

A Magnetic Resonance Compatible Knee Extension Ergometer, Youssef Jaber

Masters Theses

The product of this thesis aims to enable the study of the biochemical and physical dynamics of the lower limbs at high levels of muscle tension and fast contraction speeds. This is accomplished in part by a magnetic resonance (MR) compatible ergometer designed to apply a load as a torque of up to 420 Nm acting against knee extension at speeds as high as 4.7 rad/s. The system can also be adapted to apply the load as a force of up to 1200 N acting against full leg extension. The ergometer is designed to enable the use of magnetic resonance …

Burrowing And Walking Mechanisms Of North American Moles, Yi-Fen Lin

Doctoral Dissertations

Moles (Family Talpidae) are a classic example of extreme specialization, in their case highly derived forelimb morphologies associated with burrowing. Despite many observations of mole burrows and behaviors gathered in the field, we know very little about how and how well moles use their forelimbs to dig tunnels and to walk within the built tunnels to collect and transport food. The first chapter investigates the effect of soil compactness on two sympatric mole species under controlled laboratory conditions. My results demonstrate that increasing soil compactness impedes tunneling performance as evidenced by reduced burrowing speed, increased soil transport, shorter tunnels, shorter …

Hip Mechanics Of Unilateral Drop Landings, Bobbie S. Irmischer

Human Movement Sciences & Special Education Theses & Dissertations

Increased hip forces are a proposed factor for osteoarthritis and femoroacetabular impingement. These forces can be estimated through musculoskeletal modeling using measured kinematics and kinetics. An understanding of hip joint loading during landing in a asymptomatic population will begin to elucidate what, if any, sex differences exist and how changes in landing condition alter hip mechanics. The overall purpose of this dissertation was to explore how sex and landing condition effect landing mechanics. Landing mechanics were quantified using ground reaction forces (GRF), hip joint forces (HJF), and lower extremity kinematics during unilateral drop landings from 30-cm, 40-cm, and 50-cm, as …

The Interaction Of Scale And Temperature In Elastically Powered Movements, Jeffrey P. Olberding

USF Tampa Graduate Theses and Dissertations

For many animals, rapid movements place high power demands on underlying muscles. Storage of muscle energy in elastic structures and the subsequent rapid release of that energy can effectively amplify muscle power. Elastic recoil can also confer thermal robustness to performance in behaviors occurring at variable temperatures. Muscle contractile performance tends to decrease at lower temperatures, but elastic recoil is less affected by temperature. Here I examine the impacts of temperature and scale in systems using elastic recoil and I explore possible interactive effects on movement performance.

I explored the role that muscle contractile properties play in the differences in …

Functional Trade-Offs In Feeding Performance In Salamanders Of The Family Salamandridae, Charlotte M. Stinson

USF Tampa Graduate Theses and Dissertations

Performance is an organism’s ability to accomplish a particular task or behavior, and morphology can have a major impact on the performance of an organism. Salamanders are ecologically diverse and can feed using a variety of behaviors depending on the environment in which feeding occurs. Feeding is accomplished through the use of the hyobranchial apparatus, which lies along the oropharynx, and this structure can have competing roles; in aquatic environments the apparatus is used for suction feeding and works to depress the floor of the mouth, but during terrestrial feeding this structure projects the tongue forward out of the mouth. …

The Development Of A Platform Interface With The Use Of Virtual Reality To Enhance Upper-Extremity Prosthetic Training And Rehabilitation, Ashley D. Knight

USF Tampa Graduate Theses and Dissertations

This dissertation focuses on the investigation and development of an effective prosthetic training and rehabilitation platform with the use of virtual reality to facilitate an effective process to return amputees to the highest level of independence and functioning possible.

It has been reported that approximately 10 million people live with a limb loss worldwide, with around 30% being an upper-extremity amputee. The sudden loss of a hand or arm causes the loss of fine, coordinated movements, reduced joint range of motion (ROM), proprioceptive feedback and aesthetic appearance, all which can be improved with the use of a prosthesis and proper …

Body Size Regulation Via Bmp Signaling In Caenorhabditis Elegans, Uday Madaan

Dissertations, Theses, and Capstone Projects

The body size of an organism can be a crucial determinant of access to nutrition, reproductive success and overall survival in the wild. However, how body size of an individual is determined is incompletely understood. Body size is a complex trait determined by multiple pathways and genes, making it difficult to understand the role of individual genes and pathways in determining overall size. In Caenorhabditis elegans, a homolog of Bone Morphogenetic Proteins (BMP) is a major regulator of body size; functional loss of DBL-1 leads to a small body size. Due to a drastic change in body size in dbl-1 …

Differences In Lower Limb Kinetics In College Age Female Gymnasts To Coaches’ Perceived Efficiency In A Specific Counter Movement Jump Technique, Stephen Christopher Avgerinos

Theses and Dissertations

This thesis reports the results of a quantitative research project which examined kinetics of female collegiate gymnasts aged 18 to 21 performing a ‘punching’ counter-movement jump (CMJ) technique that is taught and required for exemplar scoring during NCAA competition. Twelve female gymnasts were recruited from the competitive team at Illinois State University. Participation was voluntary and athletes were not compensated. Each gymnast performed 8 punch-CMJ trials without coaching instruction except to perform a punching CMJ. The method of performing this CMJ began by stepping off from a 33 cm elevation, ‘punching’ off the force plates, and finishing with a landing …

Vrshape: A Virtual Reality Tool For Shaping Movement Compensation, Matthew Hale Foreman

Arts & Sciences Electronic Theses and Dissertations

The majority of persons living with chronic stroke experience some form of upper extremity motor impairment that affects their functional movement, performance of meaningful activities, and participation in the flow of daily life. Stroke survivors often compensate for these impairments by adapting their movement patterns to incorporate additional degrees of freedom at new joints and body segments. One of the most common compensatory movements is the recruitment of excessive trunk flexion when reaching with the affected upper extremity. Long-term use of these compensations may lead to suboptimal motor recovery and chronic pain or injury due to overuse. Rehabilitation focuses on …

Examining The Lumbar Movement Pattern During Functional Activities In People With Low Back Pain, Andrej Vincent Marich

Arts & Sciences Electronic Theses and Dissertations

Low back pain (LBP) is a highly prevalent condition that is often characterized by persistent pain and limitations in the performance of daily functional activities. The repeated use of altered movement patterns during the performance of daily functional activities is proposed to contribute to the development and course of LBP. Specifically, in the case of LBP, the proposed alteration of movement is one in which the lumbar spine moves more readily than other joints that can contribute to the movement. This altered movement pattern is proposed to contribute to accumulation of localized tissue stress, micro- and macro-trauma of lumbar spine …

Effects Of A Raised Surface On Lower Extremity Kinematics, Kinetics, And Muscle Activation During A Sidecut In Recreational Female Softball Players, Lauren Elizabeth Schroeder

Masters Theses

Noncontact anterior cruciate ligament (ACL) injury is a common sports-related injury. “High-risk” dynamic movements, such as a sidecut, have been associated with increasing the risk of noncontact ACL injury. Certain biomechanical abnormalities, specifically at the hip and knee, and neuromuscular abnormalities, such as unbalanced quadriceps-to-hamstrings activation ratios and certain activation patterns prior to initial contact and after initial contact, have also been associated with an increased likelihood of noncontact ACL injuries occurring. Approximately 78% of all NCAA Division I softball game-day injuries are classified as noncontact where there is no direct contact to a player. Internal derangement of the knee …

Effects Of Synthetic Turf Systems With And Without A Shock Pad On Lower Extremity Biomechanics During A 90° Cutting Movement With Differing Approach Velocities, Thomas Kenneth Elvidge

Masters Theses

The purpose of this study was to examine differences in lower extremity kinematics and kinetics on two different synthetic turf systems (turf only and turf with a shock pad) for two approach velocities (3.0 and 4.0 m/s) during a 90° cutting movement. Twelve recreational male American football and soccer players were recruited to perform five trials for each of the four conditions. A three-dimensional motion analysis system synchronized to a force platform was used to collect marker coordinate and ground reaction force (GRF) data respectively. A 2 x 2 (surface x approach velocity) ANOVA was used to analyze kinematic and …

Comparison Of Clinician Assisted Versus Unassisted Pnf Stretching On Hamstring Flexibility, Isometric Force Output, And Maximum Vertical Jump Height, Joel T. Lockhart

Theses and Dissertations

Introduction: Hamstring strains are among one of the most common acute injuries that occur in soccer players. Previous research has shown that reduced hamstring flexibility is a risk factor for injury, however this is modifiable through stretching. Some stretching techniques have contributed to decreased performance on measures important to success in sport. Proprioceptive neuromuscular facilitation (PNF) is one effective stretching technique to improve hamstring flexibility, but requires a trained partner or clinician to perform properly. It is unknown if the performance of PNF stretching without a clinician’s assistance could be as effective. It is also unknown if PNF stretching affects …

The Effects Of Trx Suspension Training On An Asymmetrical Weight Shift During A Double-Leg Squat, Samantha J. Shruck

Theses and Dissertations

Context: It is estimated that 54% of all sport related injuries are to the lower extremity, specifically the knee and ankle. Following injury, many individuals demonstrate an asymmetrical weight shift during a double-leg squat, which may increase risk of further injury. Asymmetries are driven by a variety of factors including range of motion and neuromuscular control. The goal of rehabilitation is to identify asymmetrical movement and utilize evidence-based techniques to retrain deficient movement patterns. The double-leg squat is a reliable movement task to identify asymmetrical weight shifts. Based on the theory and purpose of suspension training (TRX), it may be …

Identifying The Function Of The Calpain Small Subunit In The Mechanics Of Cell Migration, Bingqing Hao

Wayne State University Dissertations

Cell migration plays a vital role in many physiological events including: morphogenesis, wound healing, and immune response. Dysfunctional cell migration results in multiple disease states including chronic inflammation, vascular disease, and tumor metastasis, to name a few. Progress in understanding the mechanism of cell migration had been slow until the turn of the century when rapid technological advances in microscopy and omics burst to the forefront. These advances led to the realization that physical factors (dimensions, fluid shear stress, hydrostatic pressure, compression stress, environmental stiffness, and topography) have profound effects on cell migration. This study of cell mechanics has expanded …

An Investigation Of The Mechanism Of Traumatic Brain Injury Caused By Blast In The Open Field, Ke Feng

Wayne State University Dissertations

Blast-induced traumatic brain injury (bTBI) is a signature wound of modern warfare. The current incomplete understanding of its injury mechanism impedes the development of strategies for effective protection of bTBI. Despite a considerable amount of experimental animal studies focused on the evaluation of brain neurotrauma caused by blast exposure, there is very limited knowledge on the biomechanical responses of the gyrenecephalic brain subjected to primary free-field blast waves imposed in vivo, and the correlation analysis between the biomechanical responses and its injury outcomes. Such information is crucial to the development of injury criteria of bTBI.

This study aims to evaluate …

Biomechanics Of Concussion: The Importance Of Neck Tension, Ron Jadischke

Wayne State University Dissertations

Linear and angular velocity and acceleration of the head are typically correlated to concussion. Despite improvements in helmet performance to reduce accelerations, a corresponding reduction in the incidence of concussion has not occurred (National Football League [NFL] 1996 – present).

There is compelling research that forces on and deformation to the brain stem are related to concussion. The brain stem is the center of control for respiration, blood pressure and heart rate and is the root of most cranial nerves. Injury to the brain stem is consistent with most symptoms of concussion reported in the National Football League and the …

Development Of A Finite Element Pelvis And Lower Extremity Model With Growth Plates For Pediatric Pedestrian Protection, Ming Shen

Wayne State University Dissertations

Finite element (FE) model is a useful tool frequently used for investigating the injury mechanisms and designing protection countermeasures. At present, no 10 years old (YO) pedestrian FE model has been developed from appropriate anthropometries and validated against limitedly available impact response data. A 10 YO child FE pelvis and lower extremities (PLEX) model was established to fill the gap of lacking such models in this age group. The baseline model was validated against available pediatric postmortem human subjects (PMHS) test data and additional scaled adult data, then the PLEX model was integrated to build a whole-body FE model representing …