Life Sciences Commons^™

Estimates Of Persistent Inward Current Decline In Human Soleus Motor Units During Fatigue, Kirby Mendes

Theses and Dissertations (Comprehensive)

Fatigue is defined as any exercise induced reduction in strength or power, and can be attributed to central and peripheral components. Many central and peripheral mechanisms have been extensively studied, but few studies have looked at the changes in the intrinsic properties of motor neurons and their contribution to fatigue. Persistent inward current (PIC) is an important intrinsic property of motor neurons responsible for setting a large increase in the gain of motor output and may contribute to fatigue. Inhibitory inputs such as reciprocal inhibition (RI) have been shown to turn off PICs and reducing the gain of output. PIC …

An Exploratory Approach To Manipulating Dynamic Stability: Investigating The Role Of Visual Control During A Precision Foot Placement Task, Russell Cg Kennedy

Theses and Dissertations (Comprehensive)

ABSTRACT

Background: The visual system provides the body with an accurate sensory system; designed to gather information at a distance and acts as a feedforward control mechanism during human locomotion. By doing so, visual information contributes coordination of the head-arm-trunk (HAT) segment and modulating foot placement. The purpose of this study was to examine the effects of a constrained pathway during a complex navigational stone-stepping task on HAT segment control and how the visual system guides locomotion during a complex foot placement task.

Methods: Nine university-aged females (Mean age: 22.5 years old +/-1.75) participated in this study. Participants …

The Effects Of External Focus Of Attention Exercise Rehabilitation On Dual Task Walking In Parkinson's Disease, Eric N. Beck

Theses and Dissertations (Comprehensive)

Parkinson’s disease impairs control of well-learned movements, and therefore, individuals with Parkinson’s disease are forced to walk with greater conscious control. This causes difficulties while walking and completing a secondary task simultaneously (dual tasking), in that distractions from conscious control of walking increase the risk of falls and injury. Although, attention-based exercise may be a potential avenue to decrease the demands associated with walking in Parkinson’s disease. For example, an external focus of attention (on manipulated objects) has been found to recruit the networks that are important for walking with little conscious control (automatic control networks). In contrast, an internal …

The Effects Of Manipulated Somatosensory Input On Simulated Falls During Walking, Sarah Mitchell-Ewart

Theses and Dissertations (Comprehensive)

Previous research has demonstrated that there is a distinct relationship between aging and instability. The somatosensory system plays a significant role in balance control in conjunction with vision and the vestibular system (Qiu et al., 2012). Evidence has shown that manipulation of the mechanoreceptors on the plantar surface of the foot has a direct effect on balance control. By manipulating these receptors with hypothermic anesthesia and vibration, researchers are capable of simulating the effect of sensory modification on healthy individuals, in order to understand the role that plantar-surface sensation has in adapting to perturbation during gait (Perry et al., 2001; …

The 2d:4d Ratio, Handedness, And Sex Across The Age Span, Helen A M Protopapas Ms.

Theses and Dissertations (Comprehensive)

The ratio of the difference between the 2nd and 4th digits of the hand (2D:4D ratio) has been demonstrated to be an indirect indicator of prenatal testosterone levels. Prenatal testosterone has been found to play a role in brain development in utero, and thus may influence lateral asymmetries, such as handedness. Consequently, one of the aims of the current study was to examine relationships between the 2D:4D ratio, hand preference, and hand performance with the factors of sex (males and females), handedness (right handers and left handers), and age considered. A total of 104 participants were tested, 90 right handers …

The Influence Of Hip Mobility And Fatigue On Spinal Flexion And Muscle Activation In Rugby Scrum Performance, Joshua D. Clayton

Theses and Dissertations (Comprehensive)

Introduction: Rugby scrumming is a means of restarting play following a minor rule infringement that can occur up to 28 times per game. The scrum poses a significant injury risk, with more days missed due to injury per event than any other rugby activity. Rugby players also have a significantly higher rate of spine injury than the general population, perhaps due to flexion in combination with high compression forces, which has been cited as the main mechanism of injury. Flexion of the spine has also been associated with poor hip mobility and quadriceps fatigue in other athletic tasks and may …

The Influence Of Joint-Site, Limb Preference, And Physical Activity On Joint Position Sense, Amanda N. Forsyth

Theses and Dissertations (Comprehensive)

Joint position sense provides the body with information about where limb segments are relative to one another in three-dimensional space. The ability to utilize this sense is imperative for smooth, coordinated, and accurate movement in everything from activities of daily living to competitive sport (Ghez & Sainburg, 1995). Researchers currently use joint position sense as a measure of proprioceptive acuity. However, limited research has investigated the influence of potential confounding factors on proprioception. Specifically, literature on how joint-site specificity and lateral preference influence proprioception displays several incongruent findings. Therefore, the purpose of the current study was (1) to determine if …

What Lies Past Remission: The Perceived Late Effects Of Pediatric Cancer, Monica L. Molinaro

Theses and Dissertations (Comprehensive)

Objective

Pediatric cancer survival rates are increasing (Childhood Cancer Canada Foundation, 2011) and with this, so are the late effects of pediatric cancer (Oeffinger et al., 2006). This research examines the lived experiences of the perceived long-term effects of pediatric cancer on adult survivors and their primary support persons in order to understand the multifaceted nature of the illness on adults, and how it affects others close to them.

Methods

The theoretical orientation used to guide the research was phenomenology in order to present an accurate depiction of all the participants’ lived experiences. Specifically, background questionnaires were administered and one-on-one …

The Bigger Picture: Piecing Together The Experiences Of Family Members Living With High-Functioning Children With Autism Spectrum Disorder, Lauren Thomson

Theses and Dissertations (Comprehensive)

The purpose of this research was to explore the experiences of family members living with a child with ASD. The specific research questions that were addressed included: 1. How is a family member affected by having a child with ASD in the family unit; and 2. How does living with a child with ASD affect family functioning? The theoretical orientation of phenomenology was used to guide this research and to allow the “voice” of family members of children with ASD to be heard. The purpose of phenomenology is to distill individuals’ experiences with a phenomenon down to an “essence” of …

The Effects Of A Low Back Pain Vibration Modality On Trunk Postural Control, Adam R. Cornwall

Theses and Dissertations (Comprehensive)

Abstract

Introduction: Low back pain (LBP) is prevalent worldwide and is affecting even more individuals as the population ages. There has recently been an increase in production of low back pain (LBP) vibration modality belts that apply localized vibration to the lumbar region of the spine as it has shown to reduce pain. However, vibration is also known to perturb muscle spindles and thus interfere with proprioception. If a LBP vibration modality causes a proprioceptive deficit in the trunk lumbar region it could potentially increase an individual’s risk of injury due to poor postural control. Therefore, the effects of a …