Biomechanics Commons^™

Biologically-Variable Rhythmic Auditory Cues Are Superior To Isochronous Cues In Fostering Natural Gait Variability In Parkinson’S Disease, Dobromir Dotov, S. Bayard, Valérie Cochen De Cock, Christian Geny, Valérie Driss, G. Garrigue, Benoit G. Bardy, Simone Dalla Bella

Journal Articles

Introduction

Method

Effect Of Timing Of Hip Extension Assistance During Loaded Walking With A Soft Exosuit, Ye Ding, Fausto A. Panizzolo, Christopher Siviy, Philippe Malcolm, Ignacio Galiana, Kenneth G. Holt, Conor J. Walsh

Journal Articles

Background

Recent advances in wearable robotic devices have demonstrated the ability to reduce the metabolic cost of walking by assisting the ankle joint. To achieve greater gains in the future it will be important to determine optimal actuation parameters and explore the effect of assisting other joints. The aim of the present work is to investigate how the timing of hip extension assistance affects the positive mechanical power delivered by an exosuit and its effect on biological joint power and metabolic cost during loaded walking. In this study, we evaluated 4 different hip assistive profiles with different actuation timings: early-start-early-peak …

Pertinacity Volume 2 Issue 2, Yuri Hosokawa

Pertinacity

No abstract provided.

The Effect Of Skinfold On The Assessment Of The Mean Power Frequency At The Fatigue Threshold, Alyssandra N. Baniqued, Jorge M. Zuniga, Thomas C. Strunc, Katie M. Keenan, Agrini K. Boken, Jeffrey J. Anderson

Journal Articles

The purpose of this study was to determine if the amount of subcutaneous tissue over the quadriceps affects the assessment of mean power frequency at the fatigue threshold (MPFFT). It was hypothesized that greater skinfold values will result in lower power outputs associated to the MPFFT. Fourteen adults (Mean ± SD age = 20.7 ± 0.99; body weight = 72.8 ± 12.6 kg) performed an incremental cycle ergometry test to exhaustion while surface electromyographic (EMG) signals were measured from the vastus lateralis. The skinfold thickness of each leg was taken prior to the test, and skinfold thicknesses were separated into …

Hydrodynamic Performance Of Aquatic Flapping: Efficiency Of Underwater Flight In The Manta, Frank E. Fish, Christian M. Schreiber, Keith W. Moored, Geng Liu, Haibo Dong, Hilary Bart-Smith

Biology Faculty Publications

The manta is the largest marine organism to swim by dorsoventral oscillation (flapping) of the pectoral fins. The manta has been considered to swim with a high efficiency stroke, but this assertion has not been previously examined. The oscillatory swimming strokes of the manta were examined by detailing the kinematics of the pectoral fin movements swimming over a range of speeds and by analyzing simulations based on computational fluid dynamic potential flow and viscous models. These analyses showed that the fin movements are asymmetrical up- and downstrokes with both spanwise and chordwise waves interposed into the flapping motions. These motions …

Multiple Sensory Modalities Used By Squid In Successful Predator Evasion Throughout Ontogeny, Carly A. York, Ian K. Bartol, Paul S. Kruger

Biological Sciences Faculty Publications

Squid rely on multiple sensory systems for predator detection. In this study we examine the role of two sensory systems, the lateral line analogue and vision, in successful predator evasion throughout ontogeny. Squid Doryteuthis pealeii and Lolliguncula brevis were recorded using high-speed videography in the presence of natural predators under light and dark conditions with their lateral line analogue intact or ablated via a pharmacological technique. Paralarval squid showed reduced escape responses when ablated; however, no differences were found between light and dark conditions in non-ablated paralarvae, as was previously shown in juveniles and adults, indicating that the lateral line …

New Tools For Viscoelastic Spectral Analysis, With Application To The Mechanics Of Cells And Collagen Across Hierarchies, Behzad Babaei

McKelvey School of Engineering Graduate Student Theses & Dissertations

Viscoelastic relaxation spectra are essential for predicting and interpreting the mechanical responses of materials and structures. For biological tissues, these spectra must usually be estimated from viscoelastic relaxation tests. Interpreting viscoelastic relaxation tests is challenging because the inverse problem is expensive computationally. We present here (1) an efficient algorithm and (2) a quasi-linear model that enable rapid identification of the viscoelastic relaxation spectra of both linear and nonlinear materials. We then apply these methods to develop fundamental insight into the mechanics of collagenous and fibrotic tissues.

The first algorithm, which we term the discrete spectral approach, is fast enough to …

The Role Of Osteocyte Estrogen Receptor Beta (Erβ) In Regulating The Skeletal Response To Mechanical Loading, Julia P. Townsend, Russell P. Main

The Summer Undergraduate Research Fellowship (SURF) Symposium

Estrogen’s biological functions are mediated by estrogen binding to estrogen receptors (ER). Understanding what role both ERα and ERβ have in bone maintenance and formation can contribute to possible treatment of osteoporosis. This study examined osteocyte specific deletion of ERβ in mice. The cross of ERβ-floxed mice with DMP1-8kb-Cre mice provided both experimental knockout mice as well as littermate control mice. At 24 weeks of age the left tibiae of all mice were mechanically loaded five days per week for two weeks to induce bone formation. Analysis of cortical bone was conducted using microcomputed tomography (microCT) to measure load-induced changes …

Effects Of Aging On The Relationship Between Cognitive Demand And Step Variability During Dual-Task Walking, Leslie M. Decker, Fabien Cignetti, Nathaniel Hunt, Jane F. Potter, Nicholas Stergiou, Stephanie A. Studenski

Journal Articles

A U-shaped relationship between cognitive demand and gait control may exist in dual-task situations, reflecting opposing effects of external focus of attention and attentional resource competition. The purpose of the study was twofold: to examine whether gait control, as evaluated from step-to-step variability, is related to cognitive task difficulty in a U-shaped manner and to determine whether age modifies this relationship. Young and older adults walked on a treadmill without attentional requirement and while performing a dichotic listening task under three attention conditions: non-forced (NF), forced-right (FR), and forced-left (FL). The conditions increased in their attentional demand and requirement for …

A Comparison Of Cervical And Trunk Musculoskeletal Characteristics Between Female And Male Army Helicopter Pilots, Takashi Nagai, Karen A. Keenan, John P. Abt, Timothy C. Sell, Brian W. Smalley, Michael D. Wirt, Scott M. Lephart

International Journal of Aviation, Aeronautics, and Aerospace

Introduction: Neck pain (NP) and low back pain (LBP) are prevalent among military helicopter pilots. Although there have been few studies on sex differences in the NP/LBP prevalence in this population, females are shown to be at a greater risk of NP/LBP in civilian studies. This disparity may be due to musculoskeletal characteristics differences that predispose females for NP/LBP. The purpose of this study was to compare cervical and trunk musculoskeletal characteristics between male and female pilots. Methods: A total of 8 female pilots (Age: 27.6 ± 4.2yrs, HT: 166.1 ± 7.7cm, WT: 67.9 ± 10.6kg) were tested, and they …

Step By Step: Understanding Age-Related Differences In Gait Coordination And Efficiency, Elham Alijanpour

Rehabilitation Sciences Theses & Dissertations

Aging is accompanied by slower walking speed and higher metabolic cost of walking (MCoW), yet the mechanisms linking coordination and efficiency across the adult lifespan remain poorly understood. This dissertation examined how lower extremity coordination, sequencing of leg forces during the step-to-step transition (STST), and the relationship between leg forces sequencing during STST and MCoW differ with age and relate to MCoW in healthy young, middle-aged, and older adults across different walking speeds. Guided by a dynamical systems framework, age-related gait patterns were viewed as movement solutions that emerge from changing organismic constraints rather than as a failed version of …

Adding Stiffness To The Foot Modulates Soleus Force-Velocity Behaviour During Human Walking, Kota Z. Takahashi, Michael T. Gross, Herman Van Werkhoven, Stephen J. Piazza, Gregory S. Sawicki

Journal Articles

Previous studies of human locomotion indicate that foot and ankle structures can interact in complex ways. The structure of the foot defines the input and output lever arms that influences the force-generating capacity of the ankle plantar flexors during push-off. At the same time, deformation of the foot may dissipate some of the mechanical energy generated by the plantar flexors during push-off. We investigated this foot-ankle interplay during walking by adding stiffness to the foot through shoes and insoles, and characterized the resulting changes in in vivo soleus muscle-tendon mechanics using ultrasonography. Added stiffness decreased energy dissipation at the foot …

Oncology Edge Task Force On Prostate Cancer Outcomes: A Systematic Review Of Outcome Measures For Functional Mobility, Claire Davies, Genevieve Colon, Hannah Geyer, Lucinda Pfalzer, Mary Insana Fisher

Physical Therapy Faculty Publications

Background: The medical treatment of prostate cancer results in multiple impairments in body structure and declines functional abilities, resulting in activity limitations and participation restrictions. Measurement of functional mobility is an essential outcome measure in survivorship care.

Purpose: The purpose of this systematic review is to make recommendations of the best measurement tools to assess functional mobility in men treated for prostate cancer based on psychometric properties and clinical utility.

Methods: Multiple electronic databases were searched from February to March 2014. Studies of tools used to assess functional mobility were included if they met the following criteria: reported psychometric properties, …

Encoding Of Saltatory Tactile Velocity In The Adult Orofacial Somatosensory System, Rebecca Custead

College of Education and Human Sciences: Dissertations, Theses, and Student Research

Processing dynamic tactile inputs is a key function of somatosensory systems. Spatial velocity encoding mechanisms by the nervous system are important for skilled movement production and may play a role in recovery of motor function following neurological insult. Little is known about tactile velocity encoding in trigeminal networks associated with mechanosensory inputs to the face, or the consequences of movement.

High resolution functional magnetic resonance imaging (fMRI) was used to investigate the neural substrates of velocity encoding in the human orofacial somatosensory system during unilateral saltatory pneumotactile inputs to perioral hairy skin in 20 healthy adults. A custom multichannel, scalable …

The Development Of A Prosthetic Training Software For Upper Limb Amputees, Tyler Kayne Sullins

USF Tampa Graduate Theses and Dissertations

The purpose of this study was to develop an intuitive software that aids in the field of prosthetic training and rehabilitation by creating an individualized visualization of joint angles. This software is titled “the prosthetic training software (PTS) for individualized joint angle representation”, and it enables the individualized portrayal of predicted or pre-recorded joint angles. The PTS is an intuitive program for clinicians and prosthesis users that produces an animation of a virtual avatar reflecting the user’s segment lengths and amputation for rehabilitation and training purposes.

The PTS consists of a graphical user interface (GUI) and a 3D visualization of …

The Role Of Environmental Constraints In Walking: Effects Of Steering And Sharp Turns On Gait Dynamics, Dobromir Dotov, Benoit G. Bardy, Simone Dalla Bella

Journal Articles

Stride durations in gait exhibit long-range correlation (LRC) which tends to disappear with certain movement disorders. The loss of LRC has been hypothesized to result from a reduction of functional degrees of freedom of the neuromuscular apparatus. A consequence of this theory is that environmental constraints such as the ones induced during constant steering may also reduce LRC. Furthermore, obstacles may perturb control of the gait cycle and also reduce LRC. To test these predictions, seven healthy participants walked freely overground in three conditions: unconstrained, constrained (constant steering), and perturbed (frequent 90° turns). Both steering and sharp turning reduced LRC …

Prosthetic Socket Cooling System, Benjamin K. Kraw, Kathy Ha, Derek Piastrelli, Cuong Lai

Mechanical Engineering

A team of four senior-level undergraduate students in the Interdisciplinary Senior Project Design course in the Engineering Department of California Polytechnic State University: San Luis Obispo have worked to develop a prosthetic socket cooling system, namely for veteran Taylor Morris and exclusively for a transfemoral prosthetic socket, under the Quality of Life+ Laboratory. This cooling system will utilize the thermoelectric effect known as the Peltier effect to transmit heat generated from the residual limb to the surrounding environment by means of forced convection over small aluminum heat sinks. Two measurement devices have also been developed to, one, measure the heat …

Physical Testing Of Potential Football Helmet Design Enhancements, Michael Jeremy Schuster

Master's Theses

Football is a much loved sport in the United States. Unfortunately, it is also hard on the players and puts them at very high risk of concussion. To combat this an inventor in Santa Barbara brought a new design to Cal Poly to be tested.

The design was tested in small scale first in order to make some preliminary conclusions about the design. In order to fully test the helmet design; however, full scale testing was required. In order to carry out this testing a drop tower was built based on National Operating Committee on Standards for Athletic Equipment, NOCSAE, …

Range Of Motion And Plantar Foot Pressures In Those With And Without A Lateral Hip Shift During An Overhead Squat, Erin M. Lally

Theses and Dissertations

Context: Asymmetrical loading between lower limbs can theoretically be explained as an inequality of strength, neuromuscular control, or subconscious reliance on one leg more than the other. Asymmetries are often identified utilizing costly equipment such as force plates and 3D motion analysis cameras. It is important to establish less costly ways of identifying movement and loading asymmetries for clinicians to utilize. One qualitative assessment that may identify asymmetries is a ‘lateral hip shift’ during an overhead squat. Objective: To identify differences in lower extremity range of motion (ROM) and plantar foot pressures in individuals with and without a lateral hip …

Mechanics Of Early Retina And Lens Development In The Embryo, Alina Oltean

McKelvey School of Engineering Graduate Student Theses & Dissertations

Mechanical forces play an essential role in morphogenesis, the shaping of embryonic structures. This research focuses mainly on eye development, a problem that has been studied for decades using a variety of approaches. However, the mechanics of the early stages of eye formation remain incompletely understood.

The embryonic eyes begin as bilateral protrusions called optic vesicles (OVs) that grow outward from the anterior end of the brain tube. The optic vesicles contact and adhere to the overlying surface ectoderm (SE) via extracellular matrix (ECM). Then, both layers thicken in the region of contact to form the retinal and lens placodes, …