Exercise Science 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 …

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 …

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 …

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 …

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 …

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 …

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 …

Quantifying The Inter-Relationships Amongst Muscle Blood Flow, O2 Uptake And Muscle Deoxygenation Kinetics From Elevated Baseline Metabolic Rates And Increasing Work Rate Amplitudes, Lorenzo Love

Electronic Thesis and Dissertation Repository

Upon an instantaneous increase in work rate (WR), pulmonary O₂ uptake (V̇O_2p) increases in an exponential-like manner towards a new steady-state. To support this increase in V̇O_2p there is an increase in blood flow (BF; O₂ delivery) to the muscle. Previous research has shown that the rate of this increase in V̇O_2p (which defines V̇O_2p kinetics) becomes progressively slower with increasing baseline WR (WR_bl). Given the paucity of research on blood flow dynamics and underlying muscle metabolic rate, this thesis examined the effect of metabolic rate on the dynamics and relationships …

Oculomotor Task-Switching Performance Improves And Persists Following A Single Bout Of Aerobic Exercise, Diksha Shukla

Electronic Thesis and Dissertation Repository

Executive function includes the core components of response inhibition, working memory, and cognitive flexibility. Interestingly, an accumulating evidence has reported that inhibitory control and working memory improve following a single bout of exercise. It is, however, largely unclear whether cognitive flexibility elicits a similar post-exercise benefit. Accordingly, Chapter Two of my thesis examined whether 20-min of aerobic exercise provides an immediate post-exercise ‘boost’ to cognitive flexibility. Chapter Three examined for how long a putative post-exercise benefit persists. Cognitive flexibility was examined via an AABB task-switching paradigm wherein participants alternated between a well-practiced and a novel oculomotor task pre- and post-exercise. …

The Effects Of Exercise Training Versus Intensive Insulin Treatment On Skeletal Muscle Fibre Content In Type 1 Diabetes Mellitus Rodents, David P. Mcbey

Electronic Thesis and Dissertation Repository

In patients with Type I diabetes mellitus (T1DM) undergoing intensive insulin therapy, the development of insulin resistance (IR) is linked to the improper storage of intramyocellular lipid (IMCL) species. While both IR and IMCL are improved with combined aerobic and resistance training, it is unclear how these adaptations relate to individual fibre-type transitions and metabolic function. This study aimed to compare the effects of combined exercise training versus conventional and intensive insulin therapy on skeletal muscle fibres in T1DM rodents. Seventeen Sprague-Dawley rats were divided into groups: Control-Sedentary (CS; n=4), conventionally-treated T1DM sedentary (DCT; n=4), intensively-treated T1DM sedentary (DIT; n=5) …

Investigating The Simulated Diving Reflex In Professional Divers, Sydney O. Smith

Electronic Thesis and Dissertation Repository

Background: Submergence underwater activates the diving response (DR) in both diving mammals and humans in order to preserve oxygen. Some evidence suggests that the DR can be trained in humans to provide a larger magnitude of bradycardia during submergence.

Hypothesis: Individuals with breath holding experience will have a greater magnitude of bradycardia during the DR than untrained, age-matched controls.

Methods: Participants performed three different protocols: 1) an apnea to volitional end point, or until 30 seconds of involuntary breathing movements were observed (APNEA), 2) one minute of cold pack to the forehead (COLD), and 3) one minute …

Nitrate Supplementation Does Not Alter The V̇O2p Sc-Muscle Fatigue Relationship In Recreationally Active Men, James Joseph George Vanhie

Electronic Thesis and Dissertation Repository

The current study assessed alterations to the linear V̇O_2p slow component (V̇O_{2p SC})-muscle fatigue development relationship using dietary nitrate (NO_3^- ) supplementation during very heavy (VH)-intensity constant-work rate cycling exercise. Using a double- blind, block-randomised, crossover design, 8 healthy men (age, 24±2 yr [mean±SD]; V̇O_2p-max, 43.8±6.0 mL/kg/min) consumed NO_3^- -rich (BRJ) or -depleted (PLAC) beetroot juice daily for 20 d. Participants completed pre/post-condition incremental leg cycling V̇O_2p-max and 3-min “sprint” verification exercises. An initial 5 d loading phase was followed, on alternate days, by single trials of VH- or moderate-intensity …

Resedent Study- Reducing Sedentary Behaviour May Slow Cognitive Decline In Older Adults With Mild Cognitive Impairment: A Pilot Study, Kirsten B. Dillon

Electronic Thesis and Dissertation Repository

Physical activity (PA) has been shown to slow down dementia. Unfortunately, older adults spend most of their day in sedentary behaviours (SB). Breaking up prolonged bouts of sitting with intermittent bouts of light intensity PA may reduce glycemic variability in the brain; potentially mitigating cognitive decline. This study investigated how interrupting SB with 10 min bouts of light intensity PA 3x a day would affect mild to moderate cognitive impairment progression (primary outcome) in older adults residing in an assisted living facility. Participants (n=25) were assigned in clusters into a two arm 10-week single site pilot randomized controlled trial. Secondary …

A Four Week 30 S Weight Training Intervention Improves 2000 M Rowing Ergometer Performance Of Provincial And National Collegiate Female Rowers, Matthew Lee

Electronic Thesis and Dissertation Repository

This study compared the effects of a 4 week, 30 s weight training program (30SEC), to a low-repetition weight training program (LoRep), on rowing performance and aerobic capacity in preconditioned, provincial and national collegiate female rowers. 30SEC (n=5) performed 5 sets of dumbbell deadlifts (DL) and dumbbell bench pulls (BP), executing a maximum of 18 repetitions in 30 s, three times per week. LoRep (n=5) performed 4-5 sets of 2-6 repetitions of weight training exercises twice per week. Both regimes performed an identical high volume of predominantly aerobic rowing ergometer training. 30SEC improved 1 Minute Test (p2max, peak power output …

Performance Impact Of Different Lower-Limb Setup Positions In The Backstroke Swimming Start, Gordon E. Barkwell

Electronic Thesis and Dissertation Repository

The performance impact of different knee extension angles in the setup position for a backstroke start was evaluated using an instrumented starting surface. Ten backstroke swimmers completed maximum-effort starts in each of two setup positions: one with the knees flexed, and one with the knees extended. The start handles and touchpad were instrumented with tri-axial force plates. Activity of major hip and knee extensors was measured using surface electromyography. Body position was recorded throughout the start using two high-speed cameras. There was no difference in time to 10 m between the two conditions, indicating there is likely no advantage in …

Power Reserve Following Ramp-Incremental Cycling To Exhaustion: Implications For Muscle Fatigue And Function, Michael D. Hodgson

Electronic Thesis and Dissertation Repository

In ramp-incremental cycling exercise, some individuals are capable of producing power output (PO) in excess of that produced at their limit of tolerance (LoT) while others cannot. This study sought to describe the: 1) prevalence of a “power reserve” within a group of young men (n=21; mean ± SD: age 25±4 years; V̇O_2max45±8 ml•kg^-1•min^-1); and 2) muscle fatigue characteristics of those with and without a power reserve. Power reserve was determined as the difference between peak PO achieved during a ramp-incremental test to exhaustion and maximal, single-leg isokinetic dynamometer power. Pre- versus post-exercise changes …

A Simulated Walk In Nature: Testing Predictions From The Attention Restoration Theory, Corey Crossan

Electronic Thesis and Dissertation Repository

Attention Restoration Theory (ART) predicts that top-down processing during everyday activities can cause attentional fatigue and that bottom-up processing that occurs when people experience nature will be restorative (Kaplan, 1995). The present study examined this prediction by exposing participants to three different conditions using a repeated measures design: a control condition during which participants walked on a typical treadmill, a nature/restorative condition during which participants walked on the same treadmill, experiencing a simulated nature walk, and a perturbation condition that included the same simulated nature scene but also required top-down processing during the walk. The findings supported ART predictions. As …

Behaviour Change Intervention Strategies To Prevent Excessive Gestational Weight Gain In Pregnant Women Using A Nutrition And Exercise Lifestyle Intervention Program (Nelip), Karishma Hosein

Electronic Thesis and Dissertation Repository

Maternal obesity and excessive gestational weight gain (EGWG) are associated with adverse maternal and fetal outcomes. To evaluate the effectiveness of different behaviour change intervention strategies, it was hypothesized that the introduction of a single behaviour change, followed by a second, would be more effective at preventing early and total EGWG in pregnant women compared to the early simultaneous introduction of both behaviour changes. Eighteen pregnant women were block randomized into one of 3 Nutrition and Exercise Lifestyle Intervention Program (NELIP) strategies (full NELIP, Nutrition followed by Exercise N+E, Exercise followed by Nutrition E+N) and were followed at weekly face-to-face …

Insulin Resistance And T1d: The Effect Of Exercise On Skeletal Muscle Lipid Metabolism, Michelle Dotzert

Electronic Thesis and Dissertation Repository

Insulin resistance is a characteristic of Type 2 Diabetes (T2D) and metabolic syndrome, and until recently has not been considered in the context of Type 1 Diabetes (T1D). A new classification, Double Diabetes, encompasses the presence of insulin resistance in T1D. Unfortunately, these individuals are at significantly higher risk of cardiovascular complications than those with T1D alone. In T2D, abnormal skeletal muscle lipid metabolism and the accumulation of insulin desensitizing lipid metabolites contribute the development of insulin resistance. There is some evidence to suggest this occurs in the context of T1D as well. Exercise training is an effective means to …

The Effects Of Moderate Intensity Strength Training Coupled With Blood Flow Restriction: A 12 Week Intervention, Kelly Barrett

Electronic Thesis and Dissertation Repository

Blood flow restriction training (BFRT) has been suggested to increase muscle size and strength in trained and untrained individuals when using light load intensities (30 percent 1-RM). However, there is little data to support its use when working with moderate load intensities, specifically, above 50 percent of an individual’s 1-RM. The purpose of this study was to evaluate the effects of moderate load intensity BFRT on muscle size and strength of the biceps brachii after a 12 week strength training intervention. Nine, previously strength trained, participants performed an elbow flexion exercise at 70 percent of their individualized 1-RM, twice per …

The Neuroprotective Effects Of Endurance Training On The Aging Brain, Katelyn Norton

Electronic Thesis and Dissertation Repository

Dysregulation of autonomic control often develops with advancing age, favoring a chronic state of heightened sympathetic outflow with parasympathetic withdrawal. However, the mechanisms of this age-related autonomic impairment are not known and may relate to alterations in brain structure (e.g. cortical atrophy) and/or altered neural function, particularly in regions related to the cortical autonomic network, namely, the medial prefrontal cortex (MPFC), insula cortex (IC), and hippocampus (HC). Exercise exerts beneficial effects on brain structure and, in the case of cognition, neurologic function; however, how exercise affects regions of the brain related to autonomic function are not known. This thesis tested …

Indicator Amino Acid Derived Estimates Of Dietary Protein Requirement In Exercise-Trained Individuals, Arash Bandegan

Electronic Thesis and Dissertation Repository

Despite a number of nitrogen balance (NB) studies indicating increased dietary protein needs in Endurance (ET) and strength (ST) trained athletes, the Institute of Medicine (2005) has concluded, based largely on methodological concerns, that “no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise”. Indicator amino acid oxidation method (IAAO) has been recently used for determination of protein requirement in humans. This method is based on the concept that when one indispensable amino acid (AA) is deficient for protein synthesis, then all other AA, including the indicator, will be considered excess and oxidized. With increasing intakes …

Effects Of An In-Bed Resistance Exercise Program For Hospitalized High Risk Pregnant Women On Postpartum Functional Ability And Psychosocial Health, Charity Mccarthy

Electronic Thesis and Dissertation Repository

Hospitalised high-risk pregnant women (HHRPW) report physiological deconditioning similar to non-pregnant bed-rested patients. The purpose of this pilot study was to evaluate the effectiveness of an in-bed resistance exercise program to reduce the side-effects of activity-restriction in HHRPW. It was hypothesized that HHRPW who exercised while in hospital would have better functional ability and a higher quality of life at two months postpartum compared to HHRPW with no exercise program. HHRPW were activity-restricted (1940 ±1405 steps/day) in hospital and reported high rates of anxiety and depression. Nine women were randomized to either a supervised in-bed exercise (n=5) or into a …

The Effect Of A Combined Multiple-Modality Exercise Intervention On Sensorimotor Function In Community Dwelling Older Adults, With A Subjective Cognitive Complaint: The M4 Study (Multi-Modal; Mind Motor), Sam Titheridge

Electronic Thesis and Dissertation Repository

Aging is associated with the increased onset of diseases such as cognitive impairment, and ultimately dementia. Participants, 55+ years, with a self-reported cognitive complaint completed a 6-month exercise intervention. They were randomized to either a multiple modality exercise program (M2), consisting of aerobic, stretching and balancing exercises or a multiple modality plus mind motor program (M4), whereby a square stepping exercise was incorporated. Participants were assessed for reaction time (RT), movement time (MT) and % errors at baseline and at 6-months using an eye tracking 1000 system. Participants performed prosaccades and antisaccades (AS). AS RT was significantly quicker from baseline …

The Effects Of Fatigue On The Reactive Agility Test: Looking At The Difference Between Normal Game Play And The Hurry-Up Offense In Football Game Simulations, Kristine E. Walker

Electronic Thesis and Dissertation Repository

Purpose: The purpose of this study was to assess the effects of fatigue on performance of the Reactive Agility Test (RAT) by University Football players. This test assesses the athlete’s ability to change direction in response to a visual stimulus, somewhat like responding to the actions of an opponent in a game. Two fatiguing conditions were compared, simulations of normal game play and hurry-up offense in football. Methods: Following a warm-up and baseline RAT testing the athletes performed 10 high intensity, sprints on a specialized treadmill, with a 1:5 work to rest ratio to simulate regular game pace. This was …

The Effects Of A Multiple-Modality Mind-Motor Program On Vascular Outcomes In Community-Dwelling Older Adults With Subjective Cognitive Complaints, Amanda M. Deosaran

Electronic Thesis and Dissertation Repository

Studies have found a link between cardiovascular risk factors (CVRFs) and Alzheimer’s disease however; the mechanism by which CVRFs increase the risk of cognitive decline is not fully understood. The current study attempts to improve CVRFs in order to enhance cognition in older adults. Primary outcomes include ambulatory and clinical resting systolic and diastolic blood pressure (SBP; DBP). In total, 89 community-dwelling older adults with subjective cognitive complaints were randomized to either a multiple-modality mind-motor (M4) exercise or a multiple-modality (M2) exercise only. Significance was found in nighttime peak SBP (6.55 mmHg, p=.04) between groups, with a decrease in M2 …

The Effects Of Short Work Versus Longer Work Periods Within Intermittent Exercise On Vo2 Kinetics, Muscle Deoxygenation And Energy System Contribution, Michael C. Mccrudden

Electronic Thesis and Dissertation Repository

The purpose of this study was to investigate the kinetic response of oxygen uptake (V̇O₂)and muscle deoxygenation (HHb) in males (24 yr±3, n = 10) to identical heavy intensity continuous (CONT), and intermittent work; 25 s (25 s work: 3 s recovery (20W)), and 10 s (10 s work: 3 s recovery (20W)), were compared. The τV̇O₂ were similar in all conditions (CONT: 44.2 s±9; 25 s: 38.9 s±10; 10 s: 39.4 s±8, p > 0.05), whereas the HHb/ V̇O₂ overshoot decreased across conditions (p < 0.05). The increased frequency of recovery periods slowed V̇O_2p kinetics suggesting increased activity of the creatine kinase enzyme and increased …

Decreased Peak Muscle Power Is Associated With Motor Unit Loss In The Lower Limb Of Older Adults, Neal B. Mckinnon

Electronic Thesis and Dissertation Repository

This study investigated the relationship between motor unit (MU) properties and the strength and power of two lower limb muscles in healthy young and old adults. Twelve older adults (mean age, 77 ± 5 yrs) and twelve young adults (mean age, 24 ± 3 yrs) were studied. MU properties of the tibialis anterior (TA) and vastus medialis (VM) muscles were determined using decomposition-enhanced spike-triggered averaging (DE-STA). Motor unit number estimates (MUNE) of the TA were significantly reduced (p>0.05) in older adults (102 ± 76) compared to young adults (234 ± 109), primarily as a result of significantly larger surface-detected …

Post Exercise Ingestion Of Plant Vs Animal Protein Enhances Exercise Performance Outcomes Similarly, Adam N. Upshaw

Electronic Thesis and Dissertation Repository

Recently, the ingestion of a carbohydrate-protein supplement after exercise has garnered considerable interest among both athletes and scientists. However, debate exists about whether the type of protein consumed, animal vs plant, affects exercise performance differently. Thus, it is the purpose of this dissertation to compare performance outcomes following carbohydrate (CHO)-plant or CHO-animal protein ingestion utilizing a variety of exercise conditions (acute bouts of aerobic exercise, 10 weeks of strength training and six weeks of concurrent training).

Study 1 demonstrated that following a glycogen depleting bout of cycling, dairy chocolate, soy chocolate, hemp chocolate or dairy milk ingestion all enhanced the …