Darren Warburton


Relevant Degree Programs

Affiliations to Research Centres, Institutes & Clusters


Graduate Student Supervision

Doctoral Student Supervision (Jan 2008 - April 2022)
Cardiovascular risk in masters athletes (2021)

Background: Masters athletes (MAs) (>35y) are a rapidly growing population. While exercise has tremendous health benefits, there is a small absolute risk of major adverse cardiac events (MACE) in those with underlying cardiovascular disease (CVD). Prevention strategies, such as cardiovascular screening aim to identify CVD that may cause a MACE; however, they have not systematically been evaluated. Purpose: To assess cardiovascular risk in MAs and to determine the incidence, cost, and psychological implications of a screening program to detect CVD and prevent MACE in MAs. Methods: MAs underwent cardiovascular screening for five years. The screen consisted of anthropometrics, blood pressure, resting electrocardiogram, questionnaire, physical examination, and Framingham Risk Score (FRS). Participants with an abnormal screen underwent further evaluations. Impact of event scale-revised (IES-R) was used to determine the psychological impact in those diagnosed with CVD. Results: In the first year of the study, 799 MAs (63% male, 54.6 ± 9.5 years) were screened; 91 (11%) of the cohort were found to have CVD. CAD was the most common diagnosis (69.2%). During the following four years, there were an additional 89 CVD diagnoses with an incidence rate of 3.58/100, 4.14/100, 3.74/100, 1.19/100, for years two to five, respectively. A total of 10 MACE (0.30/100 athletes per year) occurred. All MACE occurred in male athletes (63.6±12.5 years). Increasing age (OR=1.05, 95%CI 1.00-1.09; p=0.038), FRS (%) (OR=1.09, 95%CI 1.03-1.16; p=0.003), and LDL cholesterol (mmol/L) (OR=1.71, 95% CI 1.22-2.40; p=0.002) were statistically significant in predicting the presence of CAD, whereas physical activity intensity and volume were not. The overall cost of the screening program was $603,465 or $3,063 per diagnosis. The initial screening year was the most expensive, yet had the highest number of diagnoses, thereby, had the lowest cost per diagnosis ($2,778). The median IES-R scores were within normal ranges. Conclusion: Yearly cardiovascular screening of MAs identified approximately 3 new diagnoses per 100 athletes per year. Despite this, MACE still occurred in MAs. In assessing MAs at risk of CAD FRS, age, and LDL-cholesterol should be utilized. Screening is justifiable, however, further research is required to refine the tools to decrease the cost.

View record

Inter-limb asymmetries in functional performance and non-contact lower-limb injury in pediatric-age athletes (2021)

Background: Previous findings regarding the association between inter-limb asymmetries in functional performance and lower-limb injury in sports are highly inconsistent, and few studies have focused on pediatric-age athletes.Purpose: To comprehensively examine inter-limb asymmetries in lower-limb functional performance and their association with non-contact lower-limb injury in pediatric-age athletes.Methods: A narrative (Chapter 2) and systematic (Chapter 3) review were composed to provide background and identify gaps. A retrospective survey was conducted to compare injury risk in laterally vs. non-laterally dominant sport in 6-17 y athletes (Chapter 4). Inter-limb asymmetry in lower-limb functional performance was assessed for 9-11 y fencers and taekwondo athletes to examine the asymmetry profile in child athletes specialized in laterally vs. non-laterally dominant sport (Chapter 5). To explore whether inter-limb asymmetry can predict injury, 456 taekwondo athletes (6-17 y) were assessed for asymmetries in unilateral jumps and Star Excursion Balance Test (SEBT), and then prospectively traced for injury for 12 months (Chapter 6). Lastly, inter-limb asymmetry in lower-limb functional performance was assessed for 9-11 y taekwondo athletes at the rested and fatigued state to explore the effects of fatigue on asymmetry (Chapter 7).Results: Greater risk of non-contact lower-limb injury was shown in athletes specialized in laterally vs. non-laterally dominant sports (Chapter 4). Inter-limb asymmetries were demonstrated in both laterally and non-laterally dominant sport, with a limb by sex interaction (Chapter 5). The increase in inter-limb asymmetry in single-leg countermovement jump height indicates greater risk of non-contact lower-limb injury in both sexes, while the increase of inter-limb asymmetry in hop and triple-hop distance indicates greater risk of non-contact lower-limb injury only in boys (Chapter 6). Inter-limb asymmetry in triple-hop distance increased with fatigue; inter-limb asymmetry in anterior reach distance in SEBT decreased with fatigue (Chapter 7).Conclusions: The current findings have important implications for pediatric sport. Inter-limb asymmetries were shown in childhood-age athletes in both laterally and non-laterally dominant sports; the amount of asymmetry can be affected by fatigue. Inter-limb asymmetries in unilateral jumps can be used to evaluate risk of non-contact lower-limb injury in pediatric-age athletes, while there is a difference between sexes.

View record

Movement behaviours and cardiovascular risk factors in individuals living with type 1 diabetes (2021)

Type 1 diabetes (T1D) is associated with an increased risk of cardiovascular disease (CVD). Research has shown that movement behaviours (physical activity, sedentary behaviour (SB), and sleep) are related to cardiovascular health; and physical activity plays an important role in the prevention of CVD and the improvement of overall health and wellbeing in individuals with T1D. The purpose of this dissertation was to evaluate cardiovascular responses to long-term exercise (Chapter 2), and acute high intensity interval (HIIE) versus moderate intensity continuous exercise (MICE) in individuals with T1D (Chapter 3); to assess movement behaviours and CVD risk factors in adolescents living with T1D, in comparison with their peers without T1D (Chapter 4); to examine the relationships between movement behaviours and CVD risk factors (Chapter 4 & 5); to investigate the combined effect of time spent in physical activity, SB and sleep which together can be considered to constitute a composite on CVD risk factors within a compositional data analysis (Chapter 6). In Chapters 2 and 3, we conducted two systematic reviews and meta-analyses. In Chapters 4, 5 and 6, 48 adolescents living with T1D and 19 of their peers living without T1D were studied, movement behaviours and CVD risk factors were assessed. We found that exercise training increased aerobic fitness and reduced glycated hemoglobin, daily insulin dosage and total cholesterol (Chapter 2) and HIIE may be safer than MICE for individuals with T1D, as it carries a lower risk of early-onset hypoglycemia without causing a higher occurrence of hyperglycemia and nocturnal hypoglycemia (Chapter 3); adolescents living with T1D presented early signs of CVD risk and demonstrated lower physical activity levels and aerobic fitness compared to their peers without T1D (Chapters 4); all participants slept less than the recommended 8 hours per night (Chapters 5) and increased sleep and decreased LIPA have negative consequences in cardiovascular health in adolescents living with T1D, (Chapters 6). Movement behaviours including regular physical activity, reducing SB, and obtaining adequate sleep play important roles in the prevention of CVD in adolescents living with T1D, optimizing these behaviours may lead to improvement of cardiovascular health in these individuals.

View record

Aquatic treadmill running: exercise testing, prescription, and the physiological response (2020)

Background: Water immersion for exercise training, recovery, and rehabilitation has been a popular and effective modality for a variety of disciplines. Recent technological advancements have led to more sports teams, research facilities, and rehabilitation clinics using aquatic treadmills (ATM) as a modern form of aquatic exercise. Purpose: The purpose of this investigation was to; 1) develop graded exercise testing criteria and evidence-based recommendations for ATM testing, 2) examine the cardiovascular response during maximal and submaximal ATM running, including ventilatory thresholds, 3) examine the hemodynamic response during submaximal ATM running, 4) determine the influence of small changes in water temperature on cardiovascular and hemodynamic responses during ATM running, and 5) explore the relationship between anthropometric measures and physiological alterations during ATM running. Methods: Participants completed a series of interventions on a land treadmill (LTM) and a HydroWorx 2000 ATM in a crossover design. Participants completed maximal graded exercise tests with a verification phase on each treadmill to compare maximal and submaximal cardiorespiratory responses, as well as determine ventilatory thresholds (VT1&VT2). Three submaximal running protocols incorporating multiple water temperatures and distances from a resistance jet were completed to determine the influence of these variables on the cardiorespiratory and hemodynamic responses. Lastly, the relationship between anthropometric measures and physiological responses during ATM running was examined.Results: Running between 0.61 metres and 0.76 metres from the resistance jet elicits the greatest cardiovascular response. The maximal and submaximal cardiorespiratory responses are similar between LTM and ATM with the exception of a lower maximal heart rate during ATM running. The use of a verification phase to confirm the attainment of V̇O2max is appropriate. VT1 and VT2 occur at similar points in each environment. ATM running alters submaximal hemodynamic responses, specifically a lower cardiac output and stroke volume. A change in water temperature of only 4C can alter the cardiovascular and hemodynamic responses during submaximal running. Anthropometric measures influence the ATM and LTM responses differently. Conclusions: These results provide compelling insight into the use of ATM to aid practitioners globally in achieving their desired results and provide a recommended standard of practice to follow in further research.

View record

Perspectives of change management and dimensions of performance management contributing to achieving sustained success in high performance sports organisations (2020)

Background: High performance sports organisations (HPSOs) operate in highly complex environments, with multiple stakeholders demanding performance, entertainment and financial results. The sports industry has evolved to create a professional domain characterised by organisational change and demands for sustained success, which has elevated leadership roles to highly skilled positions. Leaders are responsible for building, supporting and empowering multiple-discipline groups, whilst concurrently managing a plethora of change management (CM) and performance management (PM) dimensions.Purpose: The purpose of this investigation was to determine the objective markers that define sustained success in HPSOs and understand how leaders undertake CM and PM to that end. By comparing current practice with evidence-based research, the investigation sought to identify the skills leaders require to proficiently develop programs supporting sustained optimal performance.Methods: Senior leaders of HPSOs were engaged in semi-structured interviews and informal conversations to understand how each managed CM and PM in their own environment. Data was interpreted using thematic analysis and compared to peer reviewed research in order to create an understanding of the current environment.Results: From a micro perspective of CM, HPSOs demonstrating a punctuated equilibrium model of change, favoured change driven from within the organisation. Those demonstrating an emergent model of change, exhibited a bias towards change led from owners or senior executives. From a meso perspective of CM, successful change was culturally supported and guided by evidence-based systems and processes at each stage of research, planning and implementation. From a macro perspective of CM, successful initiatives were underpinned by the communication of a shared vision, process, roles and responsibilities and expectations between major stakeholders. Additionally, communication throughout the HPSO minimised organisational resistance. Strategic and operational dimensions of PM demanded a variety of “hard skills”, whilst individual management and leadership dimensions required different “soft skills”.Conclusion: Leaders must understand the micro, meso and macro perspectives of CM and demonstrate the “hard” and “soft” skills related to PM dimensions, in order to support HPSOs in achieving sustained success. These attributes must be considered during recruitment, with underdeveloped skills acknowledged by leaders and their organisations, and developed through appropriate training, coaching and mentoring.

View record

Innovations in athlete monitoring and interventions with applications in non-functional overreaching (2017)

Background: The monitoring of an athlete’s training load and cardiac function have demonstrated to be valuable assessment tools in individual sporting events. Additionally, short-term heat acclimation has shown to be effective for stimulating hypervolemia and augmenting cardiovascular performance. A gap in the literature exists indicating further research is required into both heat acclimation protocols and the monitoring of on-field training load and its cause and effect relationship with heart rate variability in team sport. Purpose: The purpose of this investigation was twofold; 1) identify a novel form of heat acclimation using hot yoga for augmenting cardiovascular and aerobic performance, and 2) identify an effective monitoring protocol suitable for team sport using internal training load and heart rate variability.Methods: The Canadian Women’s National Field Hockey team were participants for examining heat acclimation and the relationship between training load and autonomic modulation during the 2016 Olympic cycle. A maximal graded exercise test was completed prior to and following six hot yoga sessions to examine cardiovascular and aerobic performance measures.Results: In Chapter 4, six days of hot yoga developed hypovolemia that lead to trivial improvements in aerobic power, run time to exhaustion, and a small increase in running speed at each ventilatory threshold. A non-existent relationship between markers of exercise stress and alterations in plasma volume during and post hot yoga were observed. Chapter 5 identified a large relationship between the planned and achieved on field training load over a complete mesocycle. Additionally, a moderate relationship was observed between both time spent above anaerobic threshold, training load and alterations in the Ln rMSSD:R-R ratio. Chapter 6 demonstrated how alterations in the Ln rMSSD outside of the coefficient of variation may identify the development of non-functional overreaching, while an unclear relationship was observed between weekly training load and alterations in Ln rMSSDCV.Conclusion: Hot yoga may elicit a delayed hypervolemic response when recommencing exercise. In addition, individually tailored mesocycles may prevent the development of non-functional overreaching when examined using heart rate variability while further research is required to confirm the Ln rMSSDCV relationship to accumulate weekly on-field training load in team sport.

View record

Cardiac and Vascular Dynamics in Persons of Aboriginal Descent (2014)

Introduction: Aboriginal populations currently experience greater rates of cardiovascular disease, than non-Aboriginals. Limited information regarding vascular and cardiac structure and function among this population are known, despite the close relationships of cardiac and vascular physiology to cardiovascular disease.Purposes: Theses investigations evaluate cardiac and vascular dynamics of Aboriginal Canadians, directly compare vascular measures between Aboriginal and European adults and evaluate the cardiac and vascular responses to exercise among Aboriginal and European adults.Methods: In the first investigation, 55 Aboriginal adults underwent a comprehensive vascular assessment. In Study 2, 10 Aboriginal adults underwent a resting echocardiographic evaluation. Study 3 compared the vascular status of 58 Aboriginal and 58 age- and sex-matched European adults. Vascular measures were assessed pre and post-exercise among 12 Aboriginal adults and 12 age- and sex matched European adults in Study 4. Pre and post-exercise cardiac assessments were performed on 12 Aboriginal and 12 age- and sex-matched European adults in Study 5. Results: In study 1, Aboriginal male and female adults (19-91 years) were found to have similar pulse wave velocity and intima-media thickness, with males having greater systolic blood pressure and small arterial compliance, and females having greater baroreceptor sensitivity. Study 2 identified Aboriginal males having larger left ventricular mass, dimensions, and volumes, while females had greater vascular resistance. In study 3, Aboriginal adults arterial compliance and baroreceptor sensitivity was identified as being more strongly associated with blood pressure compared to Europeans. Additionally, only European hypertension (blood pressure ≥140 mmHg systolic or ≥90 mmHg diastolic) rates were found to be associated with obesity (body mass index ≥30.0 kg•m-²). Study 4 identified European adults as having greater reductions in blood pressure following exercise, with a lack of change among Aboriginal adults. In study 5, Aboriginal and European adults were found to have similar cardiac functional responses to maximal aerobic exercise, including decreases in volumes and increases in arterial-ventricular coupling; however, only Aboriginal adults demonstrated decreases in volumes and compliance, and increases in elastance and stiffness following submaximal exercise. Conclusion: Differences in factors affecting blood pressure and blood pressure responses toexercise were identified between Aboriginal and European adults.

View record

Integrity of spinal autonomic pathways in sub-acute and chronic spinal cord injuries (2013)

The outcome of spinal cord injury (SCI) is still commonly described in terms of motor andsensory function, despite increasing awareness that there is also damage to the autonomicnervous system (ANS). The purpose of this thesis was to examine the integrity of spinalautonomic pathways among individuals with sub-acute and chronic SCI. The selection ofappropriate tests to assess autonomic function is challenging since the ANS is complex.Examining reliability and comparability among measures provides a comprehensiveunderstanding of the validity of specific tools. This doctoral thesis is comprised of three separateinvestigations that focus on determining the integrity of spinal autonomic pathways followingSCI. In the first study (Chapter 2), the focus was on the reliability of heart rate variability (HRV),sympathetic skin responses (SSRs) and an orthostatic challenge (sit-up test). Measures of HRV,SSRs and blood pressure changes during the sit-up test were found to be reliable. Additionally,the sit-up test was compared with the gold standard orthostatic challenge (tilt-table test), whichrevealed that the sit-up test provokes an orthostatic response comparable to the tilt-table test. Inthe last two studies (Chapters 3 and 4) HRV and changes in blood pressure (BP) during anorthostatic challenge, SSRs and the Valsalva manoeuvre (VM) were used to examine spinalautonomic integrity. The novel focus on integrity of spinal autonomic pathways revealed that itis affected by lesion level, neurologic severity of injury, and time post-injury. As expected basedon extensive existing research on cardiovascular autonomic function following SCI, higherlesion levels produced greater cardiovascular impairments. That is, there is greater compromiseto spinal autonomic integrity in high-level compared to low-level SCI. However, the associationbetween neurologic and autonomic “completeness” of injury is unclear. Our findings suggest thattime post-injury may affect the latter. During the sub-acute stage, autonomic tests revealedcardiovascular changes in patients in a one-month follow-up after admission to a rehabilitationhospital. The exact time course of alterations to integrity is unknown. Not acknowledging changeto spinal autonomic integrity is inherently problematic since it is unclear what neurologicseverity of injury infers about autonomic dysfunction.

View record

Regulation of cerebral and systemic blood flow in humans with high level spinal cord injury: the infleunce of alpha1-agonist midodrine hydrochloride (2013)

RATIONALE: Spinal cord injury (SCI) is a devastating condition, often resulting in severe autonomic dysfunction. Secondary to autonomic dysfunction, many individuals with SCI have low blood pressure, which likely challenges the brain’s capacity to maintain suitable perfusion. Individuals with SCI suffer from a myriad of conditions that may be associated with dysfunctional regulation of cerebral blood flow (CBF), including cognitive dysfunction, orthostatic intolerance and stroke risk. Current knowledge regarding CBF regulation in SCI is limited.AIMS: To comprehensively examine cerebrovascular control in those with SCI, including: 1) the CBF response to cognition, 2) the acute CBF response to tilt, 3) the relationship between baroreflex sensitivity and CBF regulation, 4) the role arterial stiffening plays in baroreflex sensitivity, and 5) to examine the influence of increasing blood pressure through oral administration of 10 mg midodrine (alpha1-agonist). The first investigation found that the CBF response to cognition is absent in those with SCI when compared with able-bodied individuals. When restoring blood pressure to normal levels with midodrine, the CBF response to cognition was improved by 70% which was reflected in a 13% improvement in cognitive function. The second investigation showed that midodrine improved orthostatic tolerance 59% in SCI, and mitigated the reduction of CBF during tilt. The CBF response to tilt was well-maintained in SCI. The third investigation assessed the relationship between common carotid artery stiffness and baroreflex sensitivity in those with SCI. Elevated arterial stiffness (+12%) in those with SCIwere negatively related to reduced in baroreflex sensitivity (R2=0.45; p
View record

The effects of strenuous exercise on cardiovascular function in healthy men and women (2013)

No abstract available.

Patterns of physical activity and sedentary behaviour and cardiovascular health in children (2011)

Introduction: Physical activity (PA) and sedentary behaviours are important modifiable risk factorsfor cardiovascular disease in adults; however, we know much less about their role for enhancing andsustaining children’s cardiovascular health. The aim of this thesis is to evaluate the relation between PA, sedentary time, and cardiovascular health in children. Methods: Participants were volunteers in a two-year randomized controlled dissemination trial of a whole school PA model (30 schools; 1,529 children). Activity intensity was measured via accelerometry (n=629), arterial compliance by applanation tonometry (n=250), and cardiovascular fitness (CVF) using a 20-meter shuttle run test (n=1,319). Results: In study 1, epoch length influenced the volume of activity recorded; however, the direction and magnitude of the bias depended on activity intensity and volume. In study 2, girls accumulated less moderate-to-vigorous PA (MVPA) and more sedentary time compared with boys, except during physical education. Fewer girls than boys met PA guidelines during school, recess, and lunch. Similarly few boys and girls (
View record

The Effects of Endurance Training and Age on Left Ventricular Rotation (2009)

No abstract available.

Master's Student Supervision (2010 - 2021)
Co-creation of a strengths-based approach to improve cardiometabolic health: a community-based and Indigenous led healthy lifestyle intervention (2020)

Background: Finding culturally relevant and safe ways to co-create health and fitness programs that support traditional ways to be physically active are important areas of strengths-based research with Indigenous communities in Canada. Indigenous communities are returning to traditional ways of being active on the land, and colonial perceptions of health and fitness are culturally inappropriate for Indigenous communities. As such, research methodologies should focus on empowering Indigenous community leaders to be the key advocates of health behaviour change within their own communities. Objectives: This study examined the impact of a community-based and Indigenous led healthy lifestyle intervention designed specifically to improve health-related physical fitness and healthy lifestyle behaviours (reducing sedentary activity time and increasing physical activity levels) in adults (n = 15). Methodology: In collaboration and consultation with a rural and remote Indigenous community, we co-created a 13-week Indigenous led intervention incorporating individualized western exercise prescriptions and knowledge sharing circles in a group-based walking program. Measures of physical activity and sedentary behaviour (self-report and 7-day accelerometry), predicted maximal aerobic power (VO2max; 6-minute walk test), resting heart rate and blood pressure, and other health-related physical fitness measures (musculoskeletal fitness and body composition) were taken pre- and post-intervention. Results: Significant and clinically relevant improvements in aerobic fitness, resting blood pressure, and resting heart rate were observed. Accelerometry-measured moderate-to-vigorous intensity physical activity minutes were above international recommendations (~275 min/week), and sedentary activity time in bouts of >60 min reduced significantly post-intervention. No significant changes were observed in weight, body mass index, waist circumference, percentage body fat, grip strength, and flexibility. Conclusion: This work demonstrates how an Indigenous designed and led, community-based healthy lifestyle intervention can provide a culturally relevant strategy to increase health-related physical fitness, increase physical activity participation, and reduce sedentary behaviours.

View record

Exploring the impact of physical activity- and nutrition-focused workplace wellness programs on employee quality of life (2020)

Background: The majority of employed Canadians work forty hours per week, spending approximately seven hours per day at the workplace. Promoting and/or offering physical activity and proper nutrition at the workplace has been shown to increase activity and improve dietary choices both during and outside of work hours. Further, diet quality and activity levels together play major roles in a person's overall quality of life. Measuring quality of life, which includes physical, emotional, mental, and financial factors, is often conducted via survey, where results can be averaged to create an overall wellness score for each individual.Purpose: The aim of this study was to determine if nutrition and physical activity workplace wellness programs improve employee quality of life with the hypothesis that participants who participate will have higher overall wellness scores than those who do not. A systematic review with the same aim was also conducted.Methods: Twenty-eight employees at four Vancouver, BC companies with wellness programs were recruited to complete a survey. Data collection included the WellSuite® IV Health Risk Assessment for the Workforce (Non-U.S.) survey which contains 44 wellness-related questions. Employees who participated in their wellness program 25% or less of the time served as the control group. Data were described using descriptive statistics, contingency and frequency tables, ordinal logistic regression, one-way ANOVA, and independent samples T-tests.Results: The data suggests that those in the experimental group were more likely to have a higher Overall Wellness Score (p = 0.025), Fitness Score (p = 0.013), and to self-report higher life satisfaction and happiness than those in the control group. Nutrition Score increased with participation in the workplace wellness programs (p=0.035). Though limited by sample size and selection bias, this study supports the existing literature in the field and adds to the discussion on measuring quality of life outcomes of workplace wellness programs.Conclusion: The consistent and optimistic findings of this study are promising but inconclusive regarding the positive quality of life and overall health impact of workplace wellness programs that incorporate both PA and nutrition components. Future studies may benefit from aiming to limit confounding variables.

View record

A novel approach to understanding cognitive fatigue and sleep deprivation in Canadian wildland firefighters (2019)

Wildland firefighters are subject to prolonged and irregular shifts which can have detrimental effects on sleep and increase fatigue. Fatigue and sleep deprivation can reduce information-processing resulting in slower reaction times, poor decision-making, situational awareness, and hazard recognition. At present, current research on fatigue and sleep in firefighters is lacking and limited to laboratory studies. The main goal of this study was to provide insight and understanding into the impact the current wildland firefighting schedule has on the emergence of cognitive fatigue in an effort to guide future interventions that aim to improve occupational health and safety amongst wildland firefighters. This study aimed to objectively and subjectively measure sleep quantity, quality and fatigue throughout a 17-day firefighting deployment amongst firefighters in British Columbia, Canada during the fire season. During the deployment, 39 firefighters’ sleep was assessed using wrist actigraphy and subjective questionnaires. Fatigue was assessed using a cognitive performance test known as the psychomotor vigilance test. Our analysis revealed that sleep quantity was suboptimal during both fire and non-fire days. Total sleep time and sleep efficiency was less on fire days compared to non-fire days. Firefighters reported being significantly sleepier towards the end of their 14-day deployment. Our results also demonstrated that firefighters continued to report high levels of sleepiness and poor quality of sleep throughout their rest days immediately following their work deployment. Firefighters performed significantly poorer on cognitive performance tests and reported significantly higher levels of fatigue and decreased alertness near the end of their 14-day work deployment. Our results provide valuable insight into the development of fatigue across a 14-day work schedule and into the 3-day rest period for wildland firefighters. Our study highlights that firefighters may still be fatigued, sleep deprived and inadequately rested prior to their work deployment. Fire agencies and researchers should target future interventions and studies that aim to improve and manage sleep and fatigue during firefighters’ work and rest days.

View record

Examining the effectiveness of a community-based physical activity intervention on health-related physical fitness in Indigenous adults (2018)

Background: Improving the health and well-being of Indigenous peoples is a priority in Canada. A high prevalence of chronic diseases (such as cardiovascular disease, type 2 diabetes and obesity) has been reported among Indigenous communities. Despite the growing awareness of the health disparities faced by Indigenous communities compared to the general population, limited research exists on how to improve the cardio-metabolic health of Indigenous communities in culturally appropriate ways. Physical activity and fitness is well known to be of benefit for health.Objective: To evaluate the effectiveness of a community-based walking and running physical activity program on improving health-related physical fitness and other risk factors for cardiovascular disease and type 2 diabetes.Methods: Six Indigenous communities participating in the program hosted a health screening. A total of 87 adults of varying ages (44.6 ± 14.9 yr), health status and previous physical activity levels were included in this study. A trained Indigenous community member delivered weekly running and walking sessions. Aerobic fitness, muscular strength, body composition, blood pressure, total cholesterol, high density lipoprotein cholesterol, glucose, glycosylated haemoglobin and physical activity behaviour were assessed pre-and post-training.Results: Improvements in cardiorespiratory fitness and muscular strength were observed after the program. Health-related outcomes including waist circumference and blood pressure were reduced.Conclusion: A community-based physical activity program, led by an Indigenous community member, was effective at improving the cardio-metabolic health of Indigenous adults. Future research should consider modelling the design and implementation of this physical activity program when working with Indigenous communities to reduce cardio-metabolic diseases.

View record

An economic evaluation of a twelve week workplace primary prevention program (2016)

With the majority of Canadians waking hours spent at the workplace place, the financial effects of absenteeism and presenteeism due to chronic disease is increasing. Healthy lifestyle behaviours (such as physical activity, proper nutrition, smoking and alcohol reduction, and mental health management) play in reducing absenteeism and presenteeim rates is crucial. A comprehensive multi-faceted 12 week wellness program (i.e., ACCELERATION) was implemented within a workplace setting to determine its effects on absenteeism and presenteeism. One hour education sessions covered a range of topics from physical activity, proper nutrition, smoking and alcohol cessation to mental health management and stress coping. Weekly one hr exercise sessions conducted with exercise logs to monitor activity/exercise levels at home. The specialized workplace wellness program was designed to examine changes healthy lifestyle behaviours in relation to employee health status, as well as absenteeism and presenteeism costs. An economic evaluation of the ACCELERATION program was created via the distribution of online questionnaires at both baseline and a 3 month follow up. A total of 50 participants, 35 females (43.4 ± 11.5 yr) and 15 males (44.9 ± 10.5 yr) completed the 12 week program. The monetary results from the evaluation reported a reduction in absence days by 54.0% from 1.40 to 0.64 per employee and a cost savings average of $155.79 per employee. Presenteeism was reduced by 17.0% from 29.0% to 12.0% equating to an average cost savings of $420.12 per employee. These results indicate that the ACCELERATION program had a positive effect on employee health costs and is a beneficial health program for the workplace.

View record

Effects of antipsychotic medication on cardiovascular function and fitness in individuals with schizophrenia (2016)

Background: Individuals living with schizophrenia have consistently demonstrated impaired cardiovascular fitness. It is of particular interest whether antipsychotic medications significantly contribute to the reduced cardiovascular fitness in these individuals. A comprehensive review of the literature and meta-analysis was performed to examine the overall dose-dependent effect of antipsychotics on cardiovascular fitness. Also, it was tested in our participants with schizophrenia whether this dose-dependent effect might be independent of body mass index (BMI) and whether cardiovascular fitness might be further reduced in those exposed primarily to clozapine versus other antipsychotics. Methods: For our comprehensive review and meta-analysis, an electronic search of the literature was performed to identify studies that examined the effects of antipsychotics on cardiovascular fitness. For our original research investigation, 30 participants with schizophrenia or schizoaffective disorder stabilized on antipsychotics were recruited. The patients were divided into the clozapine (n = 15) and non-clozapine (n = 15) groups, and a group of healthy age- and sex-matched controls (n = 15) was included. All current antipsychotic doses were converted to chlorpromazine equivalents (CPZE). Each participant completed maximal symptom-limited exercise testing on a cycle ergometer for the assessment of peak aerobic power (VO₂peak). Results: The meta-analysis revealed an overall significant dose-dependent effect of antipsychotics on cardiovascular fitness in a total of 294 participants (correlation coefficient: -0.29, 95% CI: -0.43 to -0.14, p
View record

Novel Recovery Strategies for Elite Athletic Performance (2015)

Background: Recovery strategies aim to reduce the inflammatory response that occurs following exercise induced muscle damage (EIMD) via increased venous return. Available research is contradictory regarding whether recovery strategies are effective in reducing recovery time and improving subsequent athletic performance. As a result, further research is warranted.Purpose: To determine which application is effective in accelerating recovery for athletes following eccentric exercise, and maintaining performance.Hypothesis: We hypothesized that the VIP and CWT will be more effective compared to placebo and NormaTec conditions in facilitating recovery.Methods: 24 highly trained participants were tested over five test sessions. Participants underwent measures of VJ, 10m/30m sprints, HRV, VAS and Leg Girth. Participants underwent 100 repetitions of a plyometric drop jump and were then randomly assigned into four conditions: 1) Contrast water therapy (CWT, n=6), 2) Variable intermittent pressure (VIP, n=6), 3) NormaTec IPC (NormaTec, n= 6), 4) Passive Recovery/ Placebo (Placebo, n=6). Perception of recovery was analyzed using a Likert recovery questionnaire. Follow-up measures of outcome variables occurred at 24, 48 and 72 hr.Statistics: Two-way mixed model ANOVA was used to assess between groups and repeated measures. Tukey’s HSD was used when necessary.Results: CWT demonstrated 4.4% increase in mean VJ @ 72 hr (p > 0.05). VIP demonstrated performance maintenance for VJ and sprint measures (p > 0.05). VIP demonstrated significantly (p 0.05) occurred between groups at any time point for any other outcome measures. Conclusion: CWT and VIP appear to be beneficial in facilitating recovery and the maintenance of performance following strenuous exercise compared to placebo and NormaTec conditions. There appear to be differences in subjective perceptions of muscle soreness reflecting the differences in recovery strategy methodologies. Further research is warranted to determine the underlying mechanisms responsible for facilitating recovery and maintaining physical performance.

View record

Cardiovascular function in HER2-postivie breast cancer survivors (2014)

Background: Trastuzumab, a HER2 antagonist, has been shown to improve rates of overall survival in patients with HER2-positive breast cancer. However, cardiotoxic effects associated with treatment limits these benefits. Due to an increase in survival years, women with a history of HER2-positive breast cancer might be at increased risk of developing cardiotoxicity (i.e., LVEF
View record

Left Ventricular Twisting Mechanics During Incremental Exercise: The Influence of Aerobic Fitness and Venous Return (2012)

The role left ventricular (LV) twisting mechanics play in the stroke volume response to incremental exercise is unknown. Furthermore, the influences of aerobic fitness and venous return on LV twisting mechanics during vigorous exercise have not been investigated previously. To examine this issue, LV twisting mechanics and haemodynamics were assessed in eight endurance-trained (VO₂ max = 68.1 ± 5.6 mL∙kg⁻¹∙min⁻¹) and eight normally active (VO₂ max = 50.1 ± 5 mL∙kg⁻¹∙min⁻¹) males during incremental upright and supine exercise at rest and during heart rates of 110, 130, 150, and 170 bpm. LV twisting mechanics were measured via echocardiography, while haemodynamic measures were collected using impedance cardiography. During both incremental protocols, cardiac output increased continuously in both groups. Stroke volume (SV) and end-diastolic volume increased to a greater extent in endurance-trained athletes compared to normally active individuals during exercise in both postural positions (e.g., SV at 170 bpm supine: ET, 45%; NA, 30.5%; SV at 170 upright: ET, 44.7%; NA, 33.8%; p
View record

The Relationships Between Fundamental Movement Patterns, Spike Jump Technique, and Overuse Pain in Collegiate Volleyball Players (2012)

Despite an exceptionally high prevalence of overuse injury among elite volleyball players, very little is known about the aetiology of these conditions. Fundamental movement patterns have been found to be predictive of serious acute athletic injury, however the relationship between fundamental movement patterns and overuse injury has yet to be determined. Sport-specific jumping biomechanics have been shown to play an additional role in the development of overuse injuries in sport, and it is likely that combining fundamental and sport-specific movement assessment may possess greater predictive power than either alone. The purpose of this investigation was to evaluate how volleyball-related overuse injuries are related to fundamental movement patterns and volleyball spike jump technique. We hypothesized that volleyball players with a history of overuse injury would exhibit more dysfunctional fundamental and sport-specific movement than players without a history of injury. Fifty-seven male and female collegiate volleyball players took part in Functional Movement Screen testing, and athletes free of lower body pain (n=31) took part in a 2-dimensional kinematic analysis of spike jump technique using Dartfish video analysis software. Volleyball players with a history of overuse low back injury had significantly lower Active Straight Leg Raise scores compared to healthy players (p=0.011). Various aspects of hip mechanics during the spike jump were significantly related to a history of shoulder, low back, and knee pain (p
View record

Community-based physical activity and the risk for cardiovascular disease in aboriginal Canadians (2010)

Introduction: Aboriginal individuals continue to experience greater levels of cardiovascular disease (CVD) and diabetes than the Canadian general population, though these diseases were historically rare. Increasing evidence indicates rising sedentary behaviours from the traditional healthy and active lifestyles of this population. Various interventions have been implemented to address the health inequities in Aboriginal peoples with mixed results. Unfortunately, limited research has taken a culturally appropriate community approach to improve the health and well-being of Aboriginal peoples. By implementing a community-based and participatory physical activity (PA) and healthy living program, health and wellness can be improved in a culturally relevant context.Purposes: The primary purpose of this investigation was to examine the health benefits of a community-based PA and healthy living intervention program for Aboriginal Canadians.Methods: Participants were recruited through local Aboriginal offices representing male and female participants of wide ranging ages and CVD risk profiles. Each participant completed identical testing days pre- and post-training including a variety of CVD risk factors and four CVD risk scoring systems. Participants were self-assigned to three different community-based PA interventions including walking, walk/running, or running.Results: Significant improvements in health measures and CVD risk scores were observed for both male and female participants of all age groups. The three PA programs produce similar improvements in health measures and risk scores. Individuals of high, moderate and low CVD risk also experienced similar improvements.Discussion: High program compliance indicated success for improving PA of this population. Improvements among both genders and a variety of age groups support this program as a successful intervention for males and females of all ages. The similar changes in health status with each of the programs suggest that Aboriginal adults successfully self-select an appropriate PA intervention for health benefits. Moreover, the similarity in improvements among participants of a variety of CVD risk classifications indicates this individualized program was appropriate for improving the health status of individuals of a range of CVD risk profiles.Conclusion: The self-selected intensities Hearts inTraining program was successful in improving health status and increasing PA for Aboriginal adults of all ages, genders and risk categories.

View record

Current Students & Alumni

This is a small sample of students and/or alumni that have been supervised by this researcher. It is not meant as a comprehensive list.

Membership Status

Member of G+PS
View explanation of statuses

Program Affiliations



If this is your researcher profile you can log in to the Faculty & Staff portal to update your details and provide recruitment preferences.


Get key application advice, hear about the latest research opportunities and keep up with the latest news from UBC's graduate programs.