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The Effects Of Footwear Longitudinal Bending Stiffness On The Energetics And Biomechanics Of Uphill Running, Justin Angelo Ortega

Masters Theses

There has been a prevalence of long-distance running footwear incorporating carbon-fiber plates within their midsoles, effectively increasing their longitudinal bending stiffness (LBS). This modification of modern racing footwear has occurred concurrently with large improvements in running times (Bermon et al., 2021), putting into question how these footwear components affect performance (Muniz-Pardos et al., 2021). The current literature has investigated this at level running, but with the increasing popularity of trail running, it is of interest to investigate whether the benefits found during level running translate to graded running. Therefore, the overall aim of this study was to investigate the effects …

Functional Morphology, Biomechanics, And Evolution Of Ruminant Mammals, Abby Vander Linden

Doctoral Dissertations

Ruminant mammals, including the families Bovidae, Cervidae, Tragulidae, Moschidae, Antilocapridae, and Giraffidae, display incredible past and present diversity in morphology, ecology, and behavior. They inhabit an impressive range of environments across North and South America, Europe, Asia, and Africa, and compel the fascination of naturalists and researchers alike with their charismatic social behavior and conspicuous cranial appendages. I explore the drivers and consequences of this spectacular diversity through a comparative morphological framework, biomechanical modeling approaches, and semi-parametric and likelihood-based methods for estimating state-dependent diversification rates across the ruminant phylogeny. Together, these investigations provide evidence for adaptation via correlated evolution of …

Visuomotor Adaptation During Asymmetric Walking, Charles Napoli

Masters Theses

Necessary for effective ambulation, head stability affords optimal conditions for the perception of visual information during dynamic tasks. This maintenance of head-in-space equilibrium is achieved, in part, by the attenuation of the high frequency impact shock resulting from ground contact. While a great deal of experimentation has been done on the matter during steady state locomotion, little is known about how head stability or dynamic visual acuity is maintained during asymmetric walking.

In this study, fifteen participants were instructed to walk on a split-belt treadmill for ten minutes while verbally reporting the orientation of a randomized Landolt-C optotype that was …

Impact Of Parity On Gait Biomechanics, Bekah P. Stein

Masters Theses

Background: Symptomatic knee osteoarthritis (OA) is an incurable condition that affects nearly 50% of adults, and women are twice as likely as men to develop OA. Throughout pregnancy, women experience large changes in morphology and gait mechanics, as well as changes in joint loading. It is possible these adaptations could cause lasting changes postpartum, which may potentially contribute to initiation of OA, thereby increasing the overall risk of OA for women.

Purpose: This exploratory study looked to identify differences between lower limb gait mechanics of healthy nulliparous women and healthy parous women.

Methods: 28 healthy female participants (14 parous, 14 …

Metabolic Cost Of Asymmetrical Walking: Preferred Step Time Asymmetry Optimizes Metabolic Cost Of Walking, Jan Stenum

Doctoral Dissertations

Hemiparetic and amputee walking often has asymmetrical step lengths and step times, and it is metabolically costlier than symmetrical able-bodied walking. Consequently, asymmetry has been suggested to account for the greater energy expenditure, but the metabolic cost of asymmetrical walking is poorly understood. Conversely, even though symmetry is metabolically optimal in able-bodied walking, it is also possible that asymmetrical gait parameters may be selected if they are optimal under imposed constraints. First, to understand the metabolic cost of asymmetry, we performed experiment 1 in which we recruited 10 able-bodied subjects to walk with a range of different combinations of asymmetrical …

The Roles Of Morphology And Posture On Gait Mechanics, Russell T. Johnson

Doctoral Dissertations

Humans walk with an upright posture, extended limbs during stance, and a double-peaked vertical ground reaction force. Our closest living relatives, chimpanzees, sometimes walk bipedally but do so with a flexed, abducted hind limb. Previous researchers have studied humans walking with a crouched, chimpanzee-like gait pattern to try to infer how extinct human ancestors walked. However, it is not clear if the way humans perform this crouched posture gait would be similar to the way a species that is adapted to walk with a crouched posture would walk. The purpose of this dissertation was to investigate the impact of morphology …

Archery's Lasting Mark: A Biomechanical Analysis Of Archery, Tabitha Dorshorst

Masters Theses

The physical demands of archery involve strenuous movements that place repetitive mechanical loads on the upper body. Given that bone remodels in response to mechanical loading (Ruff, 2008), it is reasonable to assume that repetitive bow and arrow use impacts upper limb bone morphology in predictable ways. The introduction and increased use of archery have been suggested to impact bilateral humeral asymmetry (Rhodes and Knüsel, 2005; Thomas, 2014). However, this claim is yet to be tested in vivo. This project aims to use kinematic and electromyographic approaches to validate claims inferring that, 1. archery places mechanical loading on the non-dominant …

Metabolic Cost And Stability Of Locomotion In People With Lower Limb Amputation, Ryan Wedge

Doctoral Dissertations

It is generally accepted that metabolic energy expenditure and gait stability are key factors that influence the selection of able-bodied locomotor patterns. It is unclear how energy expenditure and gait stability are prioritized during walking in people with lower limb amputation. People with lower limb amputation generally have greater metabolic energy expenditure during walking and increased incidence of falls. People with unilateral lower limb amputation spend more time on the intact limb compared with the prosthetic limb, while able-bodied individuals generally walk with symmetrical timing between limbs. Restoring symmetry is often a goal of rehabilitation and assistive devices, yet the …

Microenvironment Regulates Fusion Of Breast Cancer Cells, Peiran Zhu

Masters Theses

Fusion of cancer cells has been observed in tumors for more than a century and is thought to contribute to tumor development and drug resistance. The low frequency of cell fusion events and the instability of fused cells have hindered our ability to understand the molecular mechanisms that govern cell fusion. We have developed a patterned gel system that can isolate cell fusion events and we demonstrate that several breast cancer cell lines can fuse into multinucleated giant cells in vitro, and the initiation and longevity of fused cells can be regulated solely by biophysical factors. Dynamically tuning the adhesive …

Gait Changes During Exhaustive Running, Nathaniel I. Smith

Masters Theses

Runners adopt altered gait patterns as they fatigue which may increase energy expenditure and susceptibility to certain overuse injuries. Previous investigations have described changes in muscle performance and kinematic gait variables resulting from running fatigue. The purpose of this investigation was to characterize changes in joint moment patterns that develop as runners fatigue in order to better understand the kinetic bases for kinematic fatigue effects. It was hypothesized that when fatigued, runners would demonstrate increases in stance time, peak stance phase knee flexion angle, peak knee extension moment, peak swing phase hip flexion moment, and hip extension and plantarflexion angular …

The Influence Of Musculoskeletal Geometry On The Metabolic Cost Of Pedaling, Lex Gidley

Doctoral Dissertations

The human musculoskeletal system consists of several muscles crossing each joint. In the human lower limb, most major muscles cross either one or two joints; labeled as uniarticular or biarticular muscles, respectively. The major biarticular muscles of the leg are the rectus femoris, hamstrings, and gastrocnemius. Several suggestions have been proposed as to how biarticular muscles may reduce the metabolic cost of human movement. Using experimental protocols, it is difficult to address the energetic effects of biarticular muscles, as individual muscle contributions to human movement cannot be measured and there is no way to determine what the effect might be …

Does Footfall Pattern In Forefoot Runners Change Over A Prolonged Run?, Carl W. Jewell

Masters Theses

There has been much debate on the benefits of a forefoot versus rearfoot strike pattern in distance running in terms of performance and injury prevalence. Shock attenuation occurs more prominently in soft tissues at impact in forefoot runners compared to the passive skeletal loading in rearfoot runners. Recent studies indicate that a forefoot strike pattern may not be maintainable over long distance efforts. Therefore, this study tested the hypothesis that habitual forefoot runners could not maintain their strike pattern throughout a prolonged, intensive run.

Fourteen forefoot runners ran to voluntary exhaustion on an instrumented force treadmill (average run duration: 15.4±2.2 …

Kinetic Asymmetries During Submaximal And Maximal Speed Running, Devon H. Frayne

Masters Theses

An important issue for sports scientists, coaches and athletes is an understanding of the factors within a running stride that can enhance or limit maximal running speed. Previous research has identified many sprint-related parameters as potential kinetic limiters of maximal Center of Mass velocity (Chapman and Caldwell, 1983b; Weyand et al., 2001). Bilateral asymmetry is present for many of these parameters during running; however the degree to which such asymmetries change as running speed increases is unknown. It was hypothesized that asymmetries in key sprinting parameters would be larger at maximal speed than all other tested speeds. Kinematics and kinetics …

Engineering Modeling, Analysis And Optimal Design Of Custom Foot Orthotic, Lieselle Enid Trinidad

Open Access Dissertations

This research details a procedure for the systematic design of custom foot orthotics based on simulation models and their validation through experimental and clinical studies. These models may ultimately be able to replace the use of empirical tables for designing custom foot orthotics and enable optimal design thicknesses based on the body weight and activities of end-users. Similarly, they may facilitate effortless simulation of various orthotic and loading conditions, changes in material properties, and foot deformities by simply altering model parameters. Finally, these models and the corresponding results may also form the basis for subsequent design of a new generation …

Plantar Fasciitis: Biomechanics, Atrophy And Muscle Energetics, Ryan Chang

Open Access Dissertations

Purpose: The purpose of this dissertation was to determine the effects of chronic plantar fasciitis on intrinsic foot structures with respect to biomechanics, muscle atrophy and muscle energetics. This was accomplished in three parts. Methods: In Part I, a three-dimensional motion capture system with a synchronized force platform quantified multi-segment foot model kinematics and ground reaction forces associated with walking. Healthy individuals were compared to individuals with chronic plantar fasciitis feet. Typical kinematic variables, measures of coupling, phase and variability were examined in rearfoot, forefoot and hallux segments. In Part II, foot and leg magnetic resonance images were taken in …

Engineering Analysis Of Custom Foot Orthotics, Lieselle E. Trinidad

Masters Theses 1911 - February 2014

This thesis presents an engineering approach to the modeling and analysis of custom foot orthotics. Although orthotics are widely used and accepted as devices for the prevention of and recovery from injuries, the design process continues to be based on empirical means. There have been many clinical studies investigating the various effects that the orthotics can have on the kinematics and kinetics of human locomotion. The results from these studies are not always consistent, primarily due to subject variability and experimental nature of the design. Alternatively, a better understanding of the therapeutic effects of custom foot orthotics, as well as …

Multifunctionality And Mechanical Origins: Ballistic Jaw Propulsion In Trap-Jaw Ants, Sheila Patek, J. E. Baio, B. L. Fisher, A. V. Suarez

Sheila Patek

Extreme animal movements are usually associated with a single, high-performance behavior. However, the remarkably rapid mandible strikes of the trap-jaw ant, Odontomachus bauri, can yield multiple functional outcomes. Here we investigate the biomechanics of mandible strikes in O. bauri and find that the extreme mandible movements serve two distinct functions: predation and propulsion. During predatory strikes, O. bauri mandibles close at speeds ranging from 35 to 64 m·s−1 within an average duration of 0.13 ms, far surpassing the speeds of other documented ballistic predatory appendages in the animal kingdom. The high speeds of the mandibles assist in capturing prey, while …

Squeaking With A Sliding Joint: Mechanics And Motor Control Of Sound Production In Palinurid Lobsters, Sheila Patek

Sheila Patek

The origin of arthropod sound-producing morphology typically involves modification of two translating body surfaces, such as the legs and thorax. In an unusual structural rearrangement, I show that one lineage of palinurid lobsters lost an antennal joint articulation, which transformed this joint from moving with one degree of freedom into a sliding joint with multiple degrees of freedom. With this sliding joint, `stick-and-slip' sounds are produced by rubbing the base of each antenna against the antennular plate. To understand the musculo-skeletal changes that occurred during the origin and evolutionary variation of this sound-producing mechanism, I examined joint morphology and antennal …