Kinesiology & Health Science

Permanent URI for this collectionhttps://hdl.handle.net/10315/27572

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Access status: Open Access ,
Effect of Task Error on Implicit Motor Adaptation
(2025-07-23) Rahimpoor-Marnani, Parmin; Henriques, Denise Y. P.
Motor adaptation is essential for maintaining coordination in daily activities. Implicit motor adaptation, operating unconsciously, is primarily considered to be driven by sensory prediction errors. This study aims to investigate how another error signal, task error, affects implicit adaptation across varying perturbation sizes using a visuomotor reaching paradigm. Employing a Single Trial Learning (STL) approach, we compare initial adaptation responses to different target types: a small dot target reinforcing strict spatial accuracy, and a large arc target permitting greater movement endpoint variability. By manipulating target size, we systematically alter task error presence or absence, isolating its influence on implicit motor adaptation, while holding sensory prediction error constant. These findings will advance our understanding of task error and sensory prediction error interactions in the early stages of implicit motor learning. Ultimately, this work aims to refine current motor learning models and inform targeted error type utilization in rehabilitation and training strategies.
Access status: Open Access ,
The Effects Of Dairy Consumption On Bone, Inflammatory, Antioxidant & Metabolic Biomarker Responses To Exercise Or Nutritional Stressors In Humans
(2025-07-23) Prowting, Joel; Josse, Andrea
The overall purpose of this dissertation was to examine the impact of dairy product consumption on outcomes of bone, inflammation, antioxidant & metabolic biomarkers both at rest (Chapter 5) and after exposure to different physiological stressors, including exercise (Chapter 3 & 4) and a high-calorie, high-fat meal (Chapter 6). To achieve this, two human intervention studies (divided into 4 papers) that used different stressors in combination with dairy product consumption were conducted. The collective findings indicate that increased dairy product consumption may confer some benefits to post-exercise bone remodeling and basal circulating inflammatory concentrations but does not have a significant effect on postprandial inflammatory, metabolic or glutathione responses. Therefore, including dairy products as part of a balanced diet could have minor beneficial effects if consumed following impact exercise and/or to potentially ameliorate resting low-grade chronic inflammation in people that may be at higher risk of developing metabolic disease.
Access status: Open Access ,
The Power Of Exercise: The Effect Of Age And Activity Level On Muscular Power
(2025-07-23) Desroches, Daniel Alain; Drake, Janessa D. M.
Muscle, strength, and power decline as we age, and power is critical for functional independence. This dissertation tested additional factors such as the amount and type of PA, muscular fatigue, movement mechanics, and muscle fiber type, which are known to affect power, in older adults, including masters athletes. The study involved PA questionnaires, biomechanical assessment of functional tasks including countermovement jumps (CMJ) with lower-body motion capture and a custom apparatus with embedded force plates, and MRI Dixon and DTI of the lower limb musculature and lumbar spine region. Age, sex and PA level predicted lower-body power during CMJ, with activity level demonstrating a protective effect (r=0.540) similar in magnitude to the effect of age (r=-0.654). Athletics discipline also predicted lower-body power during CMJ (r=0.389) with short distance athletes having the highest predicted power but also the most negative slope. Greater trunk flexion was associated with greater lower-body power, but older adults did not tend to use this strategy. MRI diffusion parameters weakly predicted ankle power and also differed in short distance athletes. Activity level and athletic discipline showed positive, protective effects on lower-body and joint power during the CMJ with a strength of effect comparable to that of age. Trunk flexion angle was associated with greater lower-body power output in the CMJ and was a strategy adopted only by younger adults potentially confounding the measurement of power in older adults. Overall, high levels of PA, and participation in high power track and field events is protective of muscular power and likely functional independence in older adults.
Access status: Open Access ,
Association Of Serum Carotenoids, Non-Alcoholic Fatty Liver Disease, And Metabolic Dysfunctions With All-Cause And Cardiovascular Disease Mortality
(2025-07-23) Sadrmanesh, Omidreza; Kuk, Jennifer L.
Carotenoids are antioxidants associated with a lower mortality risk in the general population. However, the association between mortality and carotenoids among individuals with non-alcoholic fatty liver disease (NAFLD) is still ambiguous. This study aimed to explore the relationship between serum carotenoids with all-cause and cardiovascular disease (CVD) mortality in those with and without NAFLD and metabolic dysfunctions. Using data from the Third National Health and Nutrition Examination Survey, Cox proportional hazard regression models were used to determine the association between serum carotenoids, NAFLD, and metabolic dysfunctions with all-cause and CVD mortality. The results showed that higher total and most individual serum carotenoid levels were associated with a lower risk of all-cause and CVD mortality in those with and without NAFLD and metabolic dysfunctions. NAFLD was independently associated with all-cause mortality, regardless of serum carotenoid levels. However, after adjustment for metabolic dysfunctions, NAFLD was not associated with all-cause mortality.
Access status: Open Access ,
The Effect of Optic Flow During Attention Related Tasks and Quiet Stance
(2025-07-23) Mahnaei, Seyedeh Feryal Feryal; Cleworth, Taylor
Vision plays a significant role in balance as it provides visual cues to help maintain balance. Increasing visual information during upright stance leads to tighter regulation of upright stance. Cognitive related tasks and postural control share capacities and compete for cognitive resources which may cause interference on one or both tasks. There is limited work on the impact of visual gain manipulation on dual tasks that include attention tasks that require visual information while maintaining an upright stance. While previous studies have explored how dual tasks and modified visual feedback influence balance separately, there is limited work on the impact of visual feedback during dual tasks that require visual information. This study explored how visual cues affect balance when combining effects of visual conditions and different cognitive attention tasks. Optic flow was amplified or reduced to 4 gain conditions (0.25x,1x,4x,16x) within virtual reality (VR) relative to the head position while participants stood quietly on a force plate that measure ground reaction forces and completed 12 randomized trials across 3 conditions. Kinematics were collected through 8 markers placed on different parts using motion capture. Muscle activity was also collected by placing EMG on 3 lower leg muscles during the trials. MSRS questionnaire was completed after each trial to assess movement consciousness. Root mean square (RMS), and the mean power frequency (MPF) of Centre of Pressure (COP) and head position (HeadPos) were used to quantify balance. The mean angle RMS of relative angular displacement of the hip, knee and ankle was calculated, and the mean angle RMS of absolute angular displacement of the trunk, thigh, shank, foot was calculated to quantify balance. Developing a greater understanding of complex dynamics of visual feedback on cognitive task that requires vision while quiet standing, may enhance our understanding of how visual information aids postural control during dual tasks.
Access status: Open Access ,
Exploring The Implementation Of Physical Activity Interventions In Long-Term Care
(2025-07-23) Geerts, Ariane; Meisner, Brad
Background: Canada’s population is aging and with it so is the demand for long-term care (LTC). Older persons living in LTC facilities can benefit from increasing their levels of physical activity however the majority of older residents spend most of their time engaged in sedentary activities and are inactive. Objective: The overarching purpose of this dissertation is to examine the implementation of physical activity interventions in LTC settings. Methods: To achieve this objective, a three-manuscript style dissertation was undertaken. Study One involved a scoping review that summarized the current use of implementation strategies and their related outcomes in the implementation of physical activity interventions in LTC. This study identified how interventions are being implemented. Study Two, focused on understanding the perspectives and experiences of researchers who have led the implementation of physical activity interventions in LTC. As part of this study, six semi-structured interventions were conducted with researchers who were involved in the interventions identified through the scoping review. Study three explored the role and contribution of allied health professionals during implementation efforts through a secondary analysis of the Safer Care for Older Persons in (residential) Environments (SCOPE) trial. Results: The scoping review identified both the implementation strategies and related outcomes that have been reported in the implementation of physical activity interventions. A consultation exercise conducted as part of this review revealed unreported implementation strategies and offered further insight into the implementation of physical activity interventions. Results from researcher interviews, conducted as part of Study Two, provided new and novel insights into the experiences and perspectives of researchers, who despite being very involved in implementation efforts have historically not been included as participants in this type of research. The third and final study explored the role and contributions of allied health professionals, another group of professionals who have similarly been underrepresented in implementation research on this topic, during implementation efforts. Conclusion: Collective, this dissertation provides new and novel insights to the understanding of physical activity intervention implementation in LTC settings. While implementation is inherently complex, these findings highlight opportunities for future research, practical implications for implementation efforts, considerations for policy development which supports activity, and broader societal implications regarding how we view and understand aging.
Access status: Open Access ,
Mental Fatigue, Planning, and Persuasive Message Exposure: A Unique Perspective in the Context of Physical Activity
(2025-07-23) Santino, Nicholas; Gunter, Rebecca L.
Existing research shapes our understanding of the effects of mental fatigue on physical activity (PA) behaviour, the importance of planning for PA to enhance PA participation, and the value of including persuasive messaging techniques within PA behaviour change interventions. However, extant literature does not directly provide understanding regarding the effects of a PA planning intervention on experiences of mental fatigue, the potential negative influence of mental fatigue on choice to plan for PA and PA plan quality, nor the potential effects of persuasive message exposure on choice to plan for PA when mentally fatigued. Study 1 explored if planning for PA heightened feelings of mental fatigue, and how individual psychological characteristics relate to experiences of mental fatigue. Study 2 examined the effects of a mentally fatiguing task on choice to plan for PA and the quality of a PA plan, as well as explored potential psychological correlates of mental fatigue. Study 3 examined if exposure to persuasive messages would influence not only choice to plan for PA, but also influence psychosocial predictors of the Health Action Process Approach (HAPA) model following a mentally fatiguing task. Changes in HAPA variables were examined as predictors of choice to plan for PA. Across these three studies, results suggest that: a) although likely not more mentally fatiguing than other daily tasks, planning for PA may still contribute to heightened feels of mental fatigue, b) experiences of heightened mental fatigue may or may not influence choice to plan for PA and PA plan quality, but trait self-control and trait grit are important psychological factors in the relationship between mental fatigue and choice to plan for PA, and c) exposure to persuasive messaging can increase the likelihood of choosing to plan for PA at a relatively high level, at least in the short term. Future researchers should attempt to better understand the relationship between mental fatigue, PA planning, and persuasive messaging by conducting studies that are mixed-method and naturalistic, with longer follow up periods to better analyze plan follow through.
Access status: Open Access ,
Exploring Perceptions of Aging and Ageism Among Personal Support Workers
(2025-07-23) Arguelles, Casey Ann Medina; Meisner, Brad
Personal Support Workers (PSWs) contribute approximately 80% of the direct care provided to older adults in a variety of care settings. There is a dearth of research on PSW perspectives despite their essential role as part of multi-professional care teams. The objective of this study was to examine views on aging and ageism among PSWs who have provided care to older adults. Semi-structured interviews were conducted with 14 PSWs in Ontario, Canada. Reflexive thematic analysis was used to analyze and generate recurrent themes. Findings demarcate some existing gaps relating to views on aging and ageism among PSWs, indicating that the quality of training and education on aging and ageism are needed to support the care PSWs deliver. Understanding the impact of age-related bias on care delivery among PSWs may improve the care received that may, in turn, improve the quality of life for older care recipients.
Access status: Open Access ,
Does an Acute Bout of Exercise Performed at the Maximal Fat Oxidation Rate Have an Impact on Human Adipose Tissue Microvascular Endothelial Cells?
(2025-07-23) Gideon, Alita Maria; Roudier, Emilie
The adipose tissue (AT) vasculature ensures healthy tissue function, supporting whole-body homeostasis. Endothelial cells (EC) line vascular capillaries and control their growth (i.e. angiogenesis). Exercising at an intensity eliciting maximal fat oxidation rate (maxFOR) increases AT blood flow and might support vascular remodelling. Yet, the impact of maxFOR on AT EC remains unknown. The workload required to achieve maxFOR was determined for 11 healthy females. Blood samples were collected pre-, immediately post- and 3h post- a 45-minute bout of aerobic exercise performed at maxFOR. Serum was isolated to treat Human Adipose Microvascular EC (HAMEC) to assess cellular behaviour and gene expression. Serum free fatty acid (FFA) concentration increased post-exercise for all participants. HAMEC had reduced migratory capacity and increased Fatty Acid Binding Protein 4 (FABP4) gene expression when treated with serum collected 3h post-exercise. Exercise at maxFOR may stabilize EC and prime AT capillaries for efficient FFA transport and uptake.
Access status: Open Access ,
A Multi-Faceted Approach to Understanding the Effects of Fatigue on Muscle and Kinematic Variability
(2025-07-23) Russell, Matthew Stephen; Hurley, Jaclyn
An in vivo human model of muscular and kinematic indeterminacy, the shoulder joint offers potential insight on how the central nervous system optimizes several competing biophysical variables. Muscle fatigue is a condition that impacts several such biophysical variables and can instigate load-sharing; centrally mediated muscle control changes utilized to manage several optimality variables like effort, metabolic cost, and joint load. However, considerable variability in fatigue-mediated shoulder kinematic and muscle activity changes has challenged the ability to make clear inferences on fatigue-mediated shoulder control changes. The goal of this dissertation was to quantify fatigue-mediated shoulder control changes from a multifaceted perspective, in hopes that comprehensive analyses and novel methodologies would further our understanding of the mechanisms that drive centrally mediated shoulder control. Of specific interest was the intent to identify factors which may explain some of the fatigue-mediated shoulder variability that remains unclear. Chapter 3 of this dissertation used coactivation ratios of the scapular stabilizers to describe muscle control changes following a shoulder fatigue task. Shoulder kinematic and coactivation responses to fatigue were variable, yet results indicated that 20-40% of individuals may increase their risk of subacromial impingement syndrome due to fatigue. Chapter 4 of this dissertation investigated how individuals adapt their fatigue-mediated muscular and kinematic responses when completing the same fatigue task from chapter 3 a second time. Participants demonstrated more aggregate kinematics on day 2, while consolidating a more mechanically efficient posture that may minimize serratus anterior fatigue exposure. Chapter 5 harnessed an optimal control biomechanical shoulder model to predict shoulder kinematics changes associated with isolated scapular stabilizer muscle weakness. This study identified a key role of serratus anterior for stabilizing arm elevation, and identified shoulder muscle synergies which may compensate for serratus anterior weakness. Chapter 6 sought to identify how fatigue-mediated changes in muscle elastic modulus may affect muscle control strategies. However, muscle stiffness appeared to be sensitive to the type of exercise/fatigue stimulus which was unforeseen and may be an important consideration for fatigue-related variability. This dissertation concludes by summarizing the integrated findings of chapters 3-6 and proposing new considerations for fatigue-mediated shoulder muscle control.
Access status: Open Access ,
Multi-Method Study On Referral And Access To Heart Function Clinics
(2025-04-10) Mamataz, Taslima; Grace, Sherry
Patients with heart failure (HF) experience significant benefits from receiving comprehensive outpatient care in specialized heart failure clinics (HF clinics). These clinics have demonstrated their effectiveness in reducing frequent HF-related hospital readmissions while maintaining cost-efficiency. Unfortunately, despite established guidelines recommending the referral of HF patients to these clinics, there exists a notable discrepancy in both access and utilization of this specialized care, creating issues of low and inequitable service utilization. The underlying reasons are largely unknown and under-researched. Therefore, this doctoral dissertation aimed to advance a scholarly understanding of factors influencing the referral decisions and access to HF clinics through a multi-method study. For this purpose, three inter-linked research studies were undertaken. Firstly, qualitative interviews were conducted with key stakeholders in HF care, including policymakers, clinic providers, and patients. This initial phase established a foundational understanding of the barriers preventing optimal access to HF clinic services. Secondly, recognizing that referring providers play a pivotal role in determining patient access to HF clinics, a mixed-method design was employed, using a sequential exploratory approach to delve into their perspectives on the challenges associated with referring patients to HF clinics. Finally, a cross-sectional survey approach was adopted to compare clinic perceptions of ideal referral criteria with those of referring providers. By identifying areas of agreement between both parties, strategies for consistent application were proposed. This dissertation contributes valuable insights for HF clinics and the broader HF community. The knowledge generated has the potential, when translated into practice, to facilitate appropriate patient access to essential HF services. The findings offer guidance to policymakers, healthcare providers, and HF patients, aiming to optimize the utilization of HF clinic services, enhance the quality of care provided, and improve overall patient outcomes.
Access status: Open Access ,
The Effects Of Age And Distraction On Interlimb Synchronization Of The Center Of Pressure
(2025-04-10) Jalalipour, Arash; Mochizuki, George
Older adults experience increased fall risk, which may be influenced by distractibility. This study examines the effects of cognitive distractions on interlimb synchronization and balance in young and older adults. Participants performed quiet standing trials on separate force plates under eyes-open and eyes-closed conditions, with and without cognitive distraction (counting by ones, backward by sevens). Interlimb synchrony was assessed using cross-correlation (CCF) of center of pressure (COP) movements, while root mean square (RMS) sway and mean sway velocity (MSV) were also analyzed. It was hypothesized that cognitive distractions would reduce synchrony, particularly in older adults. Results showed no significant differences in CCF or RMS across groups or conditions, but MSV varied significantly across conditions. These findings suggest that while cognitive distractions affect postural sway velocity, they do not significantly impact synchrony or RMS under these conditions. This study enhances our understanding of balance-cognition interactions in aging.
Access status: Open Access ,
Sex Differences In Endothelial FoxO1 Response To Nutrient And Oxidative Stress
(2025-04-10) Nahal, Manvir Singh; Tara Haas
Endothelial cells (ECs) are vital for vascular homeostasis, regulating blood flow, nutrient exchange, and immune responses. EC dysfunction contributes to diseases such as type 2 diabetes, atherosclerosis, and hypertension, with sex-specific differences in disease progression. Our lab previously observed sex differences in the response of adipose tissue ECs (ATECs) to high-fat diet-induced metabolic and oxidative stress, with females showing more favorable outcomes. Female ECs express higher Forkhead Box O1 (FoxO1) levels than males, suggesting sex-specific FoxO1 regulation. To explore this, male and female ECs were exposed to metabolic and oxidative stress, and FoxO1 subcellular localization and post-translational modifications were assessed. Male ECs showed increased FoxO1 phosphorylation and cytoplasmic localization, while females retained FoxO1 in the nucleus, supporting enhanced transcriptional potential. These findings highlight sex-dependent FoxO1 regulation, offering insights into molecular mechanisms driving sex differences in vascular health.
Access status: Open Access ,
Relationships Between Movement Behaviours And Dementia
(2025-04-10) Oye-Somefun, Akinkunle Olayemi; Ardern, Chris
The primary objectives of this dissertation were three-fold: i) to evaluate the association of movement behaviors on incident dementia through a systematic review and meta-analysis; ii) to examine the association of movement behaviors on 3-year changes in memory among middle-aged and older adults, stratified by sex; and iii) to investigate the sex-specific association between movement behaviors on cognitive function changes over three years, including the mediation effects of cardiovascular disease on cognitive function. Data from population-based cohort studies, including the Canadian Longitudinal Study of Aging (CLSA), were utilized. A systematic review and meta-analysis (SRMA), as well as general linear regression, and mediation analyses, were employed. In SRMA Study 1, regular physical activity was associated with a 28% reduction in the risk of incident dementia, while both short (<7 hours) and long (>8 hours) sleep durations were associated with an increased dementia risk (RR = 1.23 and 1.32, respectively). In CLSA Studies 2 and 3, 6-8 hours of sleep was associated with positive changes (z-scores) in immediate and delayed recall among males. Among females, the interaction of higher physical activity levels (≥10 MET-hours weekly) with 8+ hours of sleep and high sedentary time led to an increase in delayed recall. Increasing sedentary time was associated with positive changes in cognitive function in males, while excessive sleep duration was associated with a negative change in cognition. Sitting time was found to mediate the relationship between cardiometabolic components and cognitive changes over three years among males (negatively: systolic blood pressure, high-density lipoprotein, carotid intima-media thickness, glycosylated haemoglobin, and positively: waist circumference, diastolic blood pressure, and triglycerides) but not females. The relationship between sitting time and 3-year change in global cognition was further mediated through waist circumference and high-density lipoprotein among both females and males, while glycosylated hemoglobin mediated the sitting time and cognition relationship among males but not females. This dissertation highlights the importance of optimizing movement behaviors for cognitive health among older adults, emphasizing the opportunity for targeted interventions to reduce dementia risk and enhance overall cognitive functioning.
Access status: Open Access ,
Biological Ageing Of Skeletal Muscle Endothelial Cells & Responsiveness To Vegf-A: Role Of Epigenetic Writer Ezh2
(2025-04-10) Essue, Dayna Olivia; Roudier, Emilie
In the older population, the loss of small blood vessels (capillaries), known as rarefaction, precedes muscle atrophy. Aging alters the capacity of endothelial cells, the main constituents of capillaries, to form new blood vessels through angiogenesis. Epigenetics has emerged as a new research area to uncover how an ageing phenotype is acquired. Through this project we investigate how the epigenetic writer Enhancer of Zeste Homologue 2 (EZH2) regulates the pro-angiogenic pathway downstream of vascular endothelial growth factor-A (VEGF-A) and its receptor 2 (VEGFR-2) in skeletal muscle microvascular endothelial cells (SMECs) using an in-vitro model of aging. Our results suggest that EZH2 activity might restrain angiogenesis by impairing the expression of genes downstream of the VEGF-A pathway, such as Nr4a3 and Egr3. Our findings indicate that EZH2 potentially supports vascular aging. Yet, caution is required as in-vitro models, such as passaging, fails to reproduce all aspects of aging, more particularly senescence in primary cells
Access status: Open Access ,
Investigating Metabolic And Inflammatory Relationships In Two Distinct Models Of Right-Sided Cardiac Stress
(2025-04-10) Gandhi, Shivam; Perry, Christopher
This thesis summarizes data generated from two distinct models with unrelated underlying etiology that both implicate metabolic- and inflammatory-mediated adaptations in right-sided cardiac stress. The first model, Duchenne muscular dystrophy (DMD), is a neuromuscular disease caused by mutations in the X-linked DMD gene that encodes the sub-sarcolemmal protein, dystrophin. While current standards of care –glucocorticoid administration and gene-editing therapies – provide promise for skeletal muscle impairments, the effects of these interventions on dystrophic cardiomyopathy are unclear. The purpose of this thesis was to characterize chamber-specific remodeling in young D2.B10-DMDmdx/2J (D2.mdx) mice, while concurrently exploring if an adiponectin peptidomimetic (ALY688) could alleviate underlying chamber-specific pathology. Our results demonstrated that right ventricular (RV) fibrosis and cardiomyocyte hypertrophy in 4-week-old D2.mdx mice were related to lower mitochondrial respiration and increased complex I-stimulated mitochondrial H2O2. ALY688 prevented RV fibrosis and cardiomyocyte hypertrophy, concurrent with macrophage sub-population shifts towards an anti-inflammatory phenotype. Our findings identified that the dystrophic heart is heterogeneously affected, while ALY688 represents a viable intervention aimed at addressing secondary contributors to dystrophic cardiac remodeling. The second model, on-pump coronary artery bypass grafting (CABG) surgery, is a common intervention for treatment of coronary artery disease. Key to this surgery is infusion of cardioplegia, which temporarily arrests the heart so surgeons can anastomose grafts around occluded coronary arteries while blood supply is maintained by cardiopulmonary bypass. The combination of ischemia and reperfusion remains a precipitator of post-operative complications. To date, repeated-measures mitochondrial stress responses associated with CABG have never been explored in a study design that compares right atrial appendage (RAA) samples from the same patient at multiple time-points. Therefore, the purpose of this study was to investigate if post-CABG RAA exhibited alterations to mitochondrial stress responses (perturbed mitochondrial substrate-specific respiration and reactive oxygen species (ROS)-mediated protein adaptations) that correlated with patient discharge times. Preliminary findings demonstrated that CABG is associated with increased fatty acid-supported respiration on the post-CABG RAA. It is unknown if this is a protective mechanism or a detrimental mitochondrial stress response. Correlative statistics suggest that the increase in fatty acid-supported respiration and ROS-mediated adaptations do not improve patient discharge times.
Access status: Open Access ,
The Effect Of Ketogenic Diet On Hepatic Cholesterol Metabolism
(2025-04-10) Kheirandish, Aris; Ceddia, Rolando
The ketogenic diet (KD), known for its high-fat, low-carbohydrate composition, has gained popularity for weight loss and metabolic health benefits. Despite these advantages, there are concerns that the diet's high saturated fat content might elevate cholesterol levels and cardiovascular disease (CVD) risk. This study investigates the KD's impact on the molecular mechanisms of cholesterol metabolism in the liver, focusing on cholesterol synthesis markers such as 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) and sterol regulatory element-binding protein-2 (SREBP-2), as well as cholesterol uptake markers including proprotein convertase subtilisin/kexin type 9 (PCSK9) and LDL receptors (LDLr). For that, male Wistar rats (n = 6 per group) were fed for 16 weeks one of the following diets: standard chow (SC, 60% carbohydrates, 13% fat, 27% protein), high-fat sucrose-enriched (HFS, 20% carbohydrates, 60% fat, 20% protein), and ketogenic diet (KD, 0% carbohydrates, 80% fat, 20% protein). Liver tissue was extracted and analyzed for gene expression using real-time PCR and protein content using western blotting. Blood samples were collected to measure circulating cholesterol levels. We found that neither plasma cholesterol levels nor HMG-CoA reductase and SREBP-2 levels in the liver differed among the dietary interventions. However, the KD significantly reduced liver PCSK9 content and expression in comparison other diets, suggesting that the KD enhanced clearance of circulating cholesterol by the liver. To test whether there was a higher amount of LDLr on the membrane compared to the cytoplasm, the ratio of LDLr distribution between these compartments was measured. Importantly, there was an upward trend in the levels of LDLr on the membrane. In conclusion, the KD altered key steps that regulate hepatic cholesterol metabolism and prevented plasma cholesterol levels from increasing, despite its elevated saturated fat content.
Access status: Open Access ,
Investigating The Effect Of Chronic Muscle Use And Disuse On Innate Immune Signaling In Skeletal Muscle
(2025-04-10) Khemraj, Priyanka; Hood, David
Skeletal muscle health is highly dependent on the intricate mitochondrial reticulum that exhibits high levels of adaptability. It is now recognized that mitochondrial perturbations can activate innate immune pathways, such as the NLRP3 inflammasome complex, by augmenting the response against damage-associated molecular patterns (DAMPs). The objective of this study was to investigate how various metabolic conditions affect innate immune activation and mitochondrial health within skeletal muscle, which has not been fully elucidated. To investigate this, we assessed innate immune signaling pathways and mitochondrial parameters within a model of muscle denervation and an aging model combined with endurance training. Our results suggest that NLRP3 inflammasome signaling is responsive to alterations in skeletal muscle activity and can be attenuated with chronic endurance training. Furthermore, we highlight a differential response to exercise with aged muscle in innate immune signaling. This work aims to further the understanding of innate immune signaling pathways within skeletal muscle, which can potentially highlight therapeutic targets to regulate its activation under divergent metabolic conditions.
Access status: Open Access ,
Investigating The Association Between Objectively Measured Physical Activity, Trunk Endurance, And Previous Low Back Injury
(2025-04-10) Ilunga, Placide Kalala; Drake, Janessa
The goal of this study was to explore the relationship between physical activity, trunk muscle endurance, and low back pain (LBP) in an undergraduate student population. Using triaxial accelerometers and standardized endurance tests, physical activity and trunk muscle endurance were objectively measured and the results compared between the control and LBP groups. Findings indicated that while the control group generally showed higher physical activity levels, only two of fifteen variables—maximum METs and percent time in vigorous physical activity—were statistically significant. Trunk muscle endurance was higher in the control group, but a ceiling effect in the trunk endurance tests limited the ability to discover the real differences between participants. The expected correlation between physical activity and trunk muscle endurance could not be confirmed due to these limitations. This research contributes to improving the understanding of physical activity, trunk endurance, and LBP among undergraduate students.
Access status: Open Access ,
Black Feminist Geographies Of Harm Reduction: Race, Space & The Embodied Consequences Of Drug Use In Southern Ontario, Canada
(2025-04-10) Hassan, Lensa Said; De Lisio, Amanda
With the dramatic rise in overdose deaths, harm reduction strategies are urgently needed. Limited studies centre Black women and gender-diverse people (BWGDP) and their critical insights regarding harm reduction and drug-related care. This is especially important because in Canada drug criminalization repeatedly and disproportionately subject BWGDP to heightened violence. Using Southern Ontario as a research site, I examine the impact of the current policies and legislation that inform harm reduction services in relation to the unique and complex realities of BWDGP. This research is theoretically informed by the work of Black Feminist Geographies and involved the careful analysis relevant policies, semi-structured interview, and photo data to understand the living geographies of harm reduction and embodied resistance practices of BWGDP who use drugs. I argue for solutions to the state-funded harm reduction strategies that target the systems and sources of violence, in lieu of the bodies that stand in place.

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