Life Sciences Commons^™

Concussion-Related Symptomatology And Outcomes In Individuals With Mental Health Conditions: Symptom Number And Severity, Balance Performance, And Time Course To Discharge, Kathryn J. Schulze

Electronic Thesis and Dissertation Repository

Symptomatology can overlap between concussions and common mental health conditions (MHCs) – such as anxiety, depression, and attention-deficit/hyperactivity disorder. Research determined that there can be an onset of new or worsening symptoms related to pre-existing MHCs in individuals post-concussion. Pre-existing MHCs may affect concussion outcomes. Therefore, the relationship between pre-existing MHCs and concussions was further examined. Study One examined the difference in symptom severity and number of symptoms reported at the initial clinical assessment for concussion for individuals with and without a pre-existing MHC. A chart review determined that individuals with anxiety or multiple MHCs had significantly more concussion symptoms …

Sex Comparisons Of External, Anatomical And Methodological Factors On Motor Unit Firing Behavior, Michael James Marsala

Electronic Thesis and Dissertation Repository

Motor unit (MU) recruitment and firing rate (MUFR) modulation are the primary factors governing force control. Differences in the anatomical distributions of α-motoneurons, muscle properties, and perception of fatigue between males and females may cause sexually dimorphic MU firing behaviors. The purpose of this dissertation was to further examine external, anatomical, and methodological factors that may influence observations of sex-related differences in neuromuscular function. In chapter 2, sex differences in how mental fatigue may influence MU firing behaviors were examined. Mental fatigue did not significantly alter MU firing behavior, maximal force, or force tracing ability in either males or females. …

Assessing Copd Care Quality In A Rural Ontario Primary Care Clinic: A Retrospective Chart Review, Daniel Henke

Electronic Thesis and Dissertation Repository

Background: Primary chronic obstructive pulmonary disease (COPD) care may be worse in rural versus more urban environments.

Purpose: To evaluate the quality of COPD care in a rural Ontario primary care clinic.

Methods: A 12-month retrospective chart review study was conducted between June 2022 and January 2023 at a Goderich, Ontario primary care clinic. Electronic medical records (EMRs) were randomly selected for inclusion. Baseline sociodemographic (e.g., occupation) and health (e.g., smoking status) characteristics were extracted as well as information regarding COPD care received (i.e., Health Quality Ontario [HQO] Quality Standard [QS] indicators; n=33. The primary study outcome was overall proportion …

Cortical Activation During Mobility In An Indoor Real-World Environment: A Mobile Eeg Study, Sam Marshall

Electronic Thesis and Dissertation Repository

Human mobility requires neurocognitive inputs to safely navigate the environment. Previous research has examined neural processes that underly walking using mobile neuroimaging technologies, yet few studies have incorporated true real-world methods without a specific task imposed on participants (e.g., dual-task, motor demands). The present study utilized mobile electroencephalography to examine and compare theta, alpha, and beta frequency band power (μV2) in young adults during sitting and walking in laboratory and real-world environments. Our findings support that mobility and environment may modulate neural activity, as we observed increased brain activation for walking compared to sitting, and for real-world walking compared to …

The Effects Of Resistance Exercise Training On Insulin Resistance Development In Female Rodents With Type 1 Diabetes, Mitchell James Sammut

Electronic Thesis and Dissertation Repository

The etiology of insulin resistance (IR) development in type 1 diabetes mellitus (T1DM) remains unclear; however, impaired skeletal muscle metabolism may play a role. While IR development has been established in male T1DM rodents, female rodents have yet to be examined in this context. Resistance exercise training (RT) has been shown to improve IR and is associated with a lower risk of hypoglycemia onset in T1DM compared to aerobic exercise. Additionally, the molecular mechanisms mediating RT-induced improvements in insulin sensitivity remain unclear. Therefore, the purpose of this study was to investigate the effects of RT on IR development in female …

The Effect Of Central Chemoreceptors On The Peripheral Respiratory Chemoreflex Response To Hypoxia In Humans, Nasimi A. Guluzade

Electronic Thesis and Dissertation Repository

We measured the peripheral chemoreflex sensitivity to hypoxia (PChS) at various isocapnic carbon dioxide tensions (PCO₂) to determine the form of the relationship between PChS and central PCO₂. Twenty participants completed three repetitions of modified rebreathing tests with end-tidal PO₂ (P_ETO₂) clamped at 150, 70, 60, and 45 mmHg. PChS was computed at 1-mmHg intervals of P_ETCO₂ as follows: the differences in V̇_E between the three hypoxic profiles and the hyperoxic profile (∆V̇_E) were calculated; three ∆V̇_E values were plotted against corresponding calculated oxyhemoglobin …

The Ventilatory Response To Modified Rebreathing Is Unchanged By Hyperoxic Severity: Implications For The Hyperoxic Hyperventilation Paradox, Joshua D. Huggard

Electronic Thesis and Dissertation Repository

We measured the ventilatory response to hyperoxic CO₂ rebreathing with O₂ tension clamped at increasingly higher pressures. We hypothesized that the V̇_E versus PCO₂ relationship is fixed and independent of PO₂. Twenty participants (10 females; mean± SD age: 24±4 years) performed three repetitions of modified rebreathing in 4, randomized, isoxic-hyperoxic conditions: mild: PO₂=150 mmHg; moderate: PO₂=200 mmHg; high: PO₂=300 mmHg; and extreme: PO₂≈700 mmHg. For each rebreathing trial, the P_ETCO₂ at which V̇_E rose was identified as the ventilatory recruitment threshold (VRT, …

The Influence Of Knee Position And Sex On Ultrasound Imaging Of Femoral Cartilage Characteristics, Harry Battersby

Electronic Thesis and Dissertation Repository

The purpose was to examine (1) the effect of measurement position and sex on femoral cartilage outcomes, and (2) the association between gait biomechanics and cartilage outcomes. Fifty individuals participated (25 males, 25 females; Age=20.62±1.80years). Ultrasound measured femoral cartilage thickness and echo-intensity (EI) at 90º, 115º, and 140º of knee flexion. Gait outcomes included the external knee adduction and knee flexion moments. Cartilage outcomes were compared using 2(sex) x 3(position) repeated measures ANOVA. Gait and cartilage associations were assessed using stepwise regression. Cartilage was thicker when measured at 90° compared with 140°, but mainly in males. Males had thicker cartilage …

Does Acute Maximal Exercise Or Chronic Physical Activity Affect Circulating Angiotensin (1-9) Concentrations?, Kyle R. Weiman

Electronic Thesis and Dissertation Repository

Introduction: Epidemiological evidence suggests physical inactivity can increase the likelihood of hospitalization from the SARS-COV-2 virus. Further, some data indicate a greater ratio of angiotensin 1-9 to angiotensin I helps prevent severe outcomes during infection. Moreover, related hormones can enhance potentially both physical activity and health. The purpose of this study was to determine whether plasma concentrations of angiotensin (1-9) are modified after a single exhaustive exercise bout and whether sex or chronic physical activity is associated with greater plasma concentrations.

Methods: Participants (n=14) performed a graded exercise test on a cycle ergometer. Antecubital area venipunctures were performed before, immediately …

The Prevalence Of Ontario Undergraduate University Students Meeting The 24-Hour Movement Guidelines And The Role Of Perceived Social Support, Nia Contini

Electronic Thesis and Dissertation Repository

The extensive physical and mental health implications of physical activity, sedentary behaviour, and sleep are irrefutable. The COVID-19 pandemic has had drastic consequences on university students and their already poor movement behaviours. Recommendations for a healthful distribution of physical activity, sedentary behaviour, and sleep were presented in the Canadian 24-Hour Movement Guidelines for Adults. The current research sought to report the prevalence of Ontario undergraduate university students meeting the Guidelines approximately two and a half years into the pandemic and assess the association between meeting the Guidelines and perceived social support. A total of 508 undergraduate students registered at 19 …

The Neural Control Of Force Production In Response To Directional Force Challenges, Joshua W. Cohen

Electronic Thesis and Dissertation Repository

Maintenance of upright standing posture is fundamental to human mobility and requires muscular control of the body’s centre of mass over the base of support. Force production, necessary for standing, is achieved by neural activation of populations of motor units (MUs). The possibility of preferentially activating different MUs within or across synergists has been debated in the motor control literature. Accordingly, the overall objective of this dissertation was to examine the neural control of standing balance in response to different directional force challenges. High Density Surface-Electromyography (HD-sEMG) was used to observe the location of muscle activity, and signal decomposition techniques …

Plantar Flexor Dynamic Contractile Rates Are Not Dependent On Calcaneal Tendon Stiffness, Sohum Kulkarni

Electronic Thesis and Dissertation Repository

The ability to rapidly generate muscular torque and velocity is important in specialized activities and daily tasks of living. Tendon stiffness is one factor in the neuromuscular system that influences musculoskeletal torque transmission. Previous studies have reported weak-to-moderate correlations between tendon stiffness and rate of torque development (RTD). However, these correlations have been reported only for isometric contractions which may not be relevant to contractions involving joint rotation (i.e., dynamic). The purpose was to investigate the effect of calcaneal tendon stiffness on the dynamic rates of torque (RTD) and velocity (RVD) development in plantar flexor muscles. Young adult males (n=13) …

A Comparison Of Methods To Identify The Mean Response Time Of Ramp-Incremental Exercise For Exercise Prescription, Nikan Behboodpour

Electronic Thesis and Dissertation Repository

Introduction: The oxygen uptake (V̇O₂) vs power output (PO) relationship from ramp incremental exercise (RAMP) is used to prescribe aerobic exercise. As PO increases, there is a delay in V̇O₂ that contributes to a misalignment of V̇O₂ from PO making precise prescription of exercise PO untenable. Three methods of determining Mean Response Time (exponential modeling (MRT_EXP), linear modeling (MRT_LIN), and the steady-state method (MRT_SS)) were compared and evaluated for their accuracy at predicting the V̇O₂ associated with two PO below estimated lactate threshold (q_LT) and one …

The Effect Of Postural Perturbations On Cardiovascular And Skeletal Muscle Function In Healthy Adults, Patrick Siedlecki

Electronic Thesis and Dissertation Repository

Maintenance of standing balance is vital to daily living. Traditionally, perspectives on maintaining balance are achieved through the study of visual, vestibular and somatosensory inputs on motor outputs. While evidence suggests cardiovascular regulation also functions to assist postural control during orthostatic stress, how the cardiovascular system responds to postural perturbations is not well established. This dissertation includes four studies that investigated the effects of postural perturbations on the cardiovascular system and skeletal muscle responses in healthy adults. All of the studies involved exposing standing participants to surface-translation perturbations at different velocities, with known or unknown timing, and occurred while spontaneously …

Postexercise Executive Function Benefits And Cerebral Blood Flow: In The Lab And At Home, Benjamin Tari

Electronic Thesis and Dissertation Repository

A single bout of aerobic exercise improves executive function; however, the mechanism, or mechanisms, supporting this improvement remain unclear. One candidate mechanism is an exercise-mediated increase in cerebral blood flow (CBF) that enhances the efficiency of executive-related frontoparietal networks. To evaluate the link between exercise, CBF and executive function, three separate experiments were conducted. In the first study, separate 10-min sessions of moderate-to-heavy-intensity aerobic exercise, and a hypercapnic environment (i.e., 5% CO₂) were implemented. The hypercapnic condition was included because it increases CBF independent of the metabolic demands of exercise. The second study investigated whether exercise intensity-specific changes …

An Evaluation Of A Mobile Health-Health Action Process Approach Intervention To Reduce Sedentary Behaviour And Stress In Adult Office Workers - Randomized Controlled Trial, Brett Carter

Electronic Thesis and Dissertation Repository

Sedentary behaviour (SB) has been linked with a variety of negative health consequences which can be diminished by increasing frequency of breaks. The Health Action Process Approach (HAPA) is an effective behaviour change model for reducing SB in adult office workers. The objective of this study was to evaluate a mobile health HAPA-based sedentary behaviour intervention in office workers. Fifty-three participants (Mean age 40.62, 79.2% women) were randomized into a treatment group or a no-contact control group in a four-week, two-arm parallel randomized controlled trial. All SB outcomes were assessed from Baseline to Week 4, perceived stress was measured at …

Evaluating The Impact Of A Safe Exercise Training Workshop On Knowledge And Self-Efficacy To Manage Dysfunctional Exercise Among Eating Disorders Clinicians At Alsana Eating Disorders Center, Danika A. Quesnel

Electronic Thesis and Dissertation Repository

Engaging in dysfunctional exercise (DEX) is detrimental to eating disorders (EDs) prognosis, although common amongst clients. Though nutritionally supported exercise can improve ED treatment outcomes, without negatively impacting weight restoration, clinicians remain hesitant to address DEX, perhaps due to a lack of information and training. The current study examined the effects of a Safe Exercise at Every Stage (SEES) training on clinician knowledge and self-efficacy in managing DEX in ED treatment. Eating disorders clinicians completed measures before (n = 96) and after (n = 44) SEES training to assess their knowledge and self-efficacy around treating DEX, with a …

The Effect Of Breathing Patterns Common To Competitive Swimming On Gas Exchange And Muscle Deoxygenation During Heavy-Intensity Fartlek Exercise, Kevin J. Grossman

Electronic Thesis and Dissertation Repository

The purpose of this study was to compare the respiratory and muscle deoxygenation (HHb) responses of regulated breathing versus free-breathing, during continuous exercise (CONLD) and intermittent 5s breath holds (BH) (CONLD-BH), intermittent 5s sprint (FLK) and combined 5s BH and sprint (FLK-BH) followed by 25s of free-breathing. Oxygen uptake(V̇O₂)was unchanged between CONLD (2.12±0.35L/min) and CONLD-BH (2.15±0.42L/min; p=0.116), and FLK (2.24±0.40L/min) and FLK-BH (2.20±0.45L/min; p=0.861). Δ[Hb_tot]: CONLD (3.3±1.6µM) > CONLD-BH (-2.5±1.2µM; ∆177%; p<0.001), but unchanged between FLK (2.0±1.6µM) and FLK-BH (0.82±1.4µM; p=0.979). Δ[HHb]: CONLD (7.3±1.8µM) > CONLD-BH (7.0±2.0µM; ∆4%; p=0.011), and FLK (6.7±1.8µM) < FLK-BH (8.7±2.4µM; p<0.001). It is suggested that the unchanged V̇O₂ between CONLD and CONLD-BH was supported by increased deoxygenation, reflected by decreased ∆[Hb_tot] and blunted …

Understanding Para Athlete Development: An Examination Of Para Swimming, Darda J. Sales

Electronic Thesis and Dissertation Repository

Most competitively spirited individuals who engage in sport, we call them athletes, are striving to be the best they can be at their chosen discipline. To help athletes achieve their goals, several athlete development models (Côté, 1999, Gulbin et al., 2013, Higgs et al., 2019) have been produced to help coaches and sport administrators best support, and guide an athlete to achieve their optimum performance. While it has been recognized that there is contextual uniqueness to the para athlete development experience (Huetzler et al., 2016) and that there are nuances to the para athlete development experience that need to be …

Examining The Impact Of Financial Incentive Removal On Physical Activity: A Quasi-Experimental Study Of 584,760 Mobile Health Application Users, Sean Kevin Spilsbury

Electronic Thesis and Dissertation Repository

BACKGROUND: Government interest in using financial incentives (FIs) to stimulate physical activity (PA) is increasing. The cost of longer-term incentive interventions may be prohibitive, however. PURPOSE: To examine the impact of FI withdrawal on PA. METHODS: A 25-week retrospective pre-post quasi-experimental study was conducted with users of a FI-based mHealth app. Users from three Canadian provinces were included. Daily FI were removed in Ontario (ON; intervention) but not British Columbia (BC) and Newfoundland and Labrador (NL; control). Simple linear regression models were used to examine weekly mean daily step count after FI withdrawal. RESULTS: The total sample included 584,760 users …

Exercise As A Treatment For Cognitive Decline In Older Adults: The Role Of Growth Factors And Inflammatory Cytokines, Joshua A. Titus

Electronic Thesis and Dissertation Repository

The purpose of this thesis was to investigate the effects that exercise modalities have on neurotrophic and inflammatory blood markers and cognitive outcomes in older adults. A systematic review and meta-analysis were completed. The included studies illustrated that most of the literature evaluated the effect of aerobic exercise interventions on systemic concentrations of the blood marker brain-derived neurotrophic factor (BDNF). The review found that aerobic exercise increases BDNF and resistance training increases insulin-like growth factor 1 (IGF-1). Interventions with sex-specific cohorts presented advantages in males for blood marker and cognitive outcomes compared to females. One of three included interventions decreased …

Direct Electrical Stimulation Of Prefrontal Cortex Modulates The Transient Heart Rate Response To Exercise In Conscious Humans, Bartek Kulas

Electronic Thesis and Dissertation Repository

Prefrontal cortical regions play an essential role in generating appropriate cardiovascular adjustments, particularly in cardio-vagally mediated heart rate (HR) responses to active tasks. Functional imaging studies provide correlational evidence that this region coordinates HR responses to exercise, however, direct experimental evidence of prefrontal cortical HR regulation in humans is not available. Seven persons with epilepsy implanted with intracranial electroencephalography (iEEG) completed 2-second isometric handgrip (IHG) contractions at no-stimulation (NO-STIM) or sham-stimulation (SHAM) conditions, and during direct electrical stimulation (STIM) of the orbitofrontal and medial prefrontal cortex. HR responses to IHG during NO-STIM and SHAM increased HR by Δ4.9±2.7 bpm, compared …

Examining The Effects Of A Weight Stigma Induction On Psychological Stress And Exercise Outcomes, Isabella J. Randall

Electronic Thesis and Dissertation Repository

Weight stigma is highly prevalent as a motivational tool in exercise contexts. However, weight stigma experienced in this domain may contribute to lowered exercise engagement, particularly among higher-weight women. This thesis examined the effects of a weight stigma induction on psychological stress, intentions to exercise (ITE), and exercise behaviours. Higher-weight women (N = 170, M_age = 57.2) were randomly assigned to read a fictional news article (weight-stigmatizing vs neutral condition), and completed acute measures of psychological stress, ITE, and exercise behaviours 7-days later. Participants who were exposed to the stigmatizing content reported a significant increase in stress and …

A Mechanistic View Of Mental Fatigue And Motor Performance: Implications Of Sex, Physical Activity And Sleep Quality, Katie L. Kowalski

Electronic Thesis and Dissertation Repository

Sustained attention on a task leads to the development of mental fatigue, which is characterized by increases in perceived fatigue and associated with declines in submaximal exercise performance. However, the neuromuscular mechanisms underlying the relationship between mental fatigue and declines in motor performance are unclear and it is unknown if there are sex-specific responses to mental fatigue. Accordingly, the overall objective of this dissertation was to examine sex-specific differences in the impact of mental fatigue on neuromuscular function and motor performance in young adults. This objective was achieved through three studies by investigating neuromuscular function of the tibialis anterior (electrophysiological …

Examining The Feasibility Of Delivering A Multi-Component Virtual Lifestyle Medicine Program For Adults With Type 2 Diabetes, Madison S. Hiemstra

Electronic Thesis and Dissertation Repository

BACKGROUND: The virtual delivery of lifestyle medicine programs (e.g., via web-conferencing platforms) can increase program accessibility for adults living with type 2 diabetes (T2D). PURPOSE: To assess the feasibility of virtually delivering a multi-component group-based lifestyle medicine program that uses wearable technologies and exercise prescriptions in an adult population with T2D. METHODS: This was a six-week, single-cohort feasibility study. The virtual lifestyle medicine program included live-video delivery of group education classes, one-on-one exercise counselling phone calls, flash glucose monitors, wearable activity monitors, and exercise prescriptions. Several feasibility outcomes were assessed including recruitment and retention rates, acceptability (e.g., exit survey), and …

Spinal Excitability Changes Following Sensory Electrical Stimulation Of The Forearm, Devin K. Box

Electronic Thesis and Dissertation Repository

Sensory electrical stimulation can be used to suppress tremor in Parkinson’s disease. This study investigated the central mechanism underlying this suppression in healthy participants. Reciprocal inhibition (RI) of the wrist flexors before and after a session of sensory electrical stimulation (SES) applied to the antagonistic extensor muscles was assessed using electromyography. It was hypothesized that a 15-minute session of SES, rated by participants as a 3 on a 0-10 pain scale, would produce an increase in RI. Seven of the 18 participants experienced an increase in RI at 0-5 minutes post stimulation, which returned to baseline at 10-15 minutes. The …

“One Of The Most Elaborate Doping Ploys In Sports History”: The Impact Of The 2016 Russian Doping Scandal On Anti-Doping, Wada And Athletes’ Rights, Mikael J. Gonsalves

Electronic Thesis and Dissertation Repository

This dissertation analyzes the impacts of the 2016 Russian doping scandal from a philosophical and historical perspective. This dissertation’s second chapter, the article entitled (1) “The Brave New World of Athletes’ Rights: A Canadian Perspective on Significant Shifts for the World Anti- Doping Agency” in time for the World Anti-Doping Agency’s (WADA) 20 th anniversary, puts into words the new investigative reality of contemporary anti-doping. It explains a new attitude of anti-doping authorities in response to the ‘game-changing’ Russian manipulation of samples, what has been described as “one of the most elaborate doping ploys in sports history” 1 (Icarus, 2016) …

Post-Activation Potentiation Induced By Concentric Contractions At Three Speeds In Humans, Alexander Zero

Electronic Thesis and Dissertation Repository

Post-activation potentiation (PAP) is the acute enhancement of contractile properties following a short duration (<10s) high intensity contraction. Compared with isometric contractions, little is known about the PAP response induced by concentric conditioning contractions (CCs) and the effect of contractile speeds. In the dorsiflexors of 10 participants, twitch responses were measured following 5s of maximal effort concentric CCs at each of 10, 20 and 50°/s. Concentric PAP responses were compared to a maximal isometric voluntary contraction (MVC) matched for contraction time. Additionally, concentric CCs were compared to isometric CCs matched for mean torque, contraction area and time. The principal finding was that the PAP response following maximal concentric CCs was independent of contractile speed and, there was no difference in the PAP response between concentric CCs and an isometric MVC. Maximal contractions, regardless of contraction modality, likely produce sufficient Ca²⁺ to induce a full PAP response, and thus there was no difference between speeds or contraction type. Concentric CCs had significantly larger peak twitch torque than their isometric torque matches (49-58%), and faster maximal rates of torque development at the three speeds (62-77%). However, these responses are likely related to greater muscle activation (EMG), and not contraction modality per se. Thus, PAP responses following maximal concentric CCs are not affected by velocity and responses are not different from an isometric MVC. This indicates maximal …

Sexual Dimorphism In Response To Repetitive Bouts Of Acute Exercise In Rodents With Type 1 Diabetes Mellitus, Jordan C. Larocque

Electronic Thesis and Dissertation Repository

The purpose of this study was to examine sex-specific differences in the blood glucose (BG) response to recurrent aerobic exercise in type 1 diabetes. Specifically, we examined the role of peak estrogen (E2) concentrations during proestrus on BG response to prolonged aerobic exercise. To do so, nineteen Sprague-Dawley rats were assigned to four exercised groups: control female (CXF; n = 5), control male (CXM; n = 5), diabetic female (DXF, n = 5) and diabetic male (DXM, n = 4). Diabetes was induced in DX groups via subcutaneous injection of low dose streptozotocin. After four days of exercise, liver glycogen …

Recognizing Parasport Impacts: Ripples, Waves, And Echoes, Adam J. Purdy

Electronic Thesis and Dissertation Repository

Major Games such as the 2015 Parapan American Games in Toronto (TO2015) generate the potential to bring awareness to sport participation opportunities for people with impairment (Chalip et al, 2017). In the post-games era, it is important to examine the ways in which sport program managers recognize the outcomes of games-related leveraging initiatives. Teleconference interviews were conducted with twelve program managers in the Greater Toronto Area. The study followed an interpretive descriptive methodology and employed a theoretical construct of recognition as a novel approach to assess the legacy and social impacts of hosting parasport games. A form of thematic analysis …