• The nature experiences of wilderness recreation leaders : throwing a stone

      Grimwood, Bryan S. R.; Applied Health Sciences Program (Brock University, 2005-05-21)
      Through this descriptive exploratory study, the ways that wilderness recreation leaders experience nature are illuminated, deconstructing the assumed environmental benefits of and practices used in outdoor recreation (Haluza-Delay, 2001). This study also offers a foundation for advancing an environmental ethic among wilderness recreation leaders, participants, and organizations. With the continued degradation of and threats to natural environments, and the rising popularity of outdoor recreation participation, the outdoor recreation professional can be a leader in promoting human reconnections to the Earth (Henderson, 1999). Leaders of outdoor recreation experiences play an important role in encouraging these revived relationships to natural settings and can contribute to the necessary environmental consciousness shift needed within Western society (Hanna, 1995; Jordan, 1996). The purpose of this research was to describe the lived-experience in nature of wilderness recreation leaders. Specifically, a phenomenological method of inquiry was used to describe the meaning of nature, the connections and relationships to nature, and the behaviours and emotions experienced in nature by a group of wilderness canoe trip leaders employed by a residential summer camp. In addition to the implications of this research, achieving this outcome provides a rich descriptive understanding of wilderness leaders' experiences—a basis from which to extend future research endeavours and programmatic practices that promote effective environmental outcomes of outdoor recreation participation. Each of the five study participants was employed in the summer of 2003 by an Ontario residential summer camp organization that sponsors extended wilderness river canoe trips for youth. Two in-depth and semi-structured interviews were performed with each participant, asking them to reflect on the canoe trip that they led for the summer camp organization during 2003. Phenomenological data was analyzed according to Colaizzi's (1978) thematic analysis process. Consistent with van Manen's (1997) emphasis on phenomenological writing, the final result presents the essence of the nature experiences of wilderness recreation leaders in the format of a narrative description. This narrative piece is the culmination of this research effort. Throughout the journey, however, various foundations within the outdoor recreation field, such as minimum impact principles, environmentally responsible behaviours, anthropocentric and ecocentric worldviews, and effective leadership are deconstructed and discussed.
    • Neuromotor Mechanisms Involved in the Recovery from Local Muscular Fatigue

      Green, Lara; Applied Health Sciences Program (Brock University, 2013-01-14)
      The phenomenon of over-recovery consists of a participant’s maximal force levels returning to values above initial levels. The present study examined the presence and causes of over-recovery following local muscular fatigue. Fourteen males completed two fatigue protocols consisting of maximal isometric dorsiflexion contractions. Upon completion of the fatigue protocol participants’ force was monitored over a 15 minute recovery period. Dorsiflexion force and surface electromyography (sEMG) from the tibialis anterior and soleus were monitored concurrently. Following the two fatigue conditions (10 and 20% force decrement) force recovered to 100.5 and 99.5% of initial levels for each condition, respectively. Surface EMG root-mean-square amplitude and MPF exhibited changes consistent with a warm-up effect. It was concluded that over-recovery was not present in the tibialis anterior following a local muscular fatigue. However, the return in force to initial values, rather than a persistent decrement as normally observed, was mediated by the warm-up effect.
    • Neuromuscular adaptations in endurance-trained boys and men

      Cohen, Rotem.; Applied Health Sciences Program (Brock University, 2009-01-28)
      Competitive sports participation in youth is becoming increasingly more common in the Western world. It is widely accepted that sports participation, specifically endurance training, is beneficial for physical, psychomotor, and social development of children. The research on the effect of endurance training in children has focused mainly on healthrelated benefits and physiological adaptations, particularly on maximal oxygen uptake. However, corresponding research on neuromuscular adaptations to endurance training and the latter's possible effects on muscle strength in youth is lacking. In children and adults, resistance training can enhance strength and mcrease muscle activation. However, data on the effect of endurance training on strength and neuromuscular adaptations are limited. While some evidence exists demonstrating increased muscle activation and possibly increased strength in endurance athletes compared with untrained adults, the neuromuscular adaptations to endurance training in children have not been examined. Thus, the purpose of this study was to examine maximal isometric torque and rate of torque development (RID), along with the pattern of muscle activation during elbow and knee flexion and extension in muscle-endurancetrained and untrained men and boys. Subjects included 65 males: untrained boys (n=18), endurance-trained boys (n=12), untrained men (n=20) and endurance-trained men (n=15). Maximal isometric torque and rate of torque development were measured using an isokinetic dynamometer (Biodex III), and neuromuscular activation was assessed using surface electromyography (SEMG). Muscle strength and activation were assessed in the dominant arm and leg, in a cross-balanced fashion during elbow and knee flexion and extension. The main variables included peak torque (T), RTD, rate of muscle activation (Q30), Electro-mechanical delay (EMD), time to peak RTD and co-activation index. Age differences in T, RTD, electro-mechanical delay (EMD) and rate of muscle activation (Q30) were consistently observed in the four contractions tested. Additionally, Q30, nonnalized for peak EMG amplitude, was consistently higher in the endurancetrained men compared with untrained men. Co-activation index was generally low in all contractions. For example, during maximal voluntary isometric knee extension, men were stronger, had higher RTD and Q30, whether absolute or nonnalized values were used. Moreover, boys exhibited longer EMD (64.8 ± 18.5 ms vs. 56.6 ± 15.3 ms, for boys and men respectively) and time to peak RTD (112.4 ± 33.4 ms vs. 100.8 ± 39.1 ms for boys and men, respectively). In addition, endurance-trained men had lower T compared with untrained men, yet they also exhibited significantly higher nonnalized Q30 (1.9 ± 1.2 vs. 1.1 ± 0.7 for endurance-trained men and untrained men, respectively). No training effect was apparent in the boys. In conclusion, the findings demonstrate muscle strength and activation to be lower in children compared with adults, regardless of training status. The higher Q30 of the endurance-trained men suggests neural adaptations, similar to those expected in response to resistance training. The lower peak torque may su9gest a higher relative involvement oftype I muscle fibres in the endurance-trained athletes. Future research is required to better understand the effect of growth and development on muscle strength and activation patterns during dynamic and sub-maximal isometric contractions. Furthennore, training intervention studies could reveal the effects of endurance training during different developmental stages, as well as in different muscle groups.
    • Neuromuscular responses to an isometric force and position task during passive hyperthermia

      Coletta, Nico; Applied Health Sciences Program
      Mechanisms of central nervous system (CNS) impairment during hyperthermia are largely task-dependent. This thesis sought to compare neuromuscular responses of an isometric force and position task during passive hyperthermia, and the relative contributions of rectal (Tre) and skin (T ̅sk) temperature afferents. Surface electromyography (sEMG) was used to assess the electrical activity of the flexor carpi radialis (FCR) muscle during a force and position task. Twenty participants were passively heated from 37.1°C to 39.0°C Tre or thermal tolerance and then cooled back to 37.8°C using a liquid conditioning garment. Passive hyperthermia induced progressive increases in root-mean-square (RMS) amplitude, mean power frequency (MPF) and median power frequency (MDF) for the force task. No change was observed in the sEMG signal for the positon task with passive heating, yet RMS amplitude increased upon skin cooling. Discrepancies in the sEMG signal exist between isometric and dynamic tasks, and these changes are due to core and skin afferents, respectively.
    • Ontario high school sport : an investigation of organizational design and its context

      Sarson, Lindsay A.; Applied Health Sciences Program (Brock University, 2005-05-19)
      In 2002, The Ontario Federation of School Athletic Associations (OFSAA) identified that in providing extracurricular sport programs schools are faced with the 'new realities' of the education system. Although research has been conducted exploring the pressures impacting the provision of extracurricular school sport (Donnelly, Mcloy, Petherick, & Safai, 2000), few studies within the field have focused on understanding extracurricular school sport from an organizational level. The focus of this study was to examine the organizational design (structure, systems, and values) of the extracurricular sport department within three Ontario high schools, as well as to understand the context within which the departments exist. A qualitative multiple case study design was adopted and three public high schools were selected from one district school board in Ontario to represent the cases under investigation. Interviews, observations and documents were used to analyze the extracurricular sport department design of each case and to better understand the context within which the departments exist. As the result of the analysis of the structure, systems and values of each case, two designs emerged- Design KT1 and Design KT2. Differences in the characteristics of design archetype KT1 and KT2 centered on the design dimension of values, and therefore this study identified that contrasting organizational values reflect differences in design types. The characteristics of the Kitchen Table archetype were found to be transferable to the sub-sector of extracurricular school sport, and therefore this research provides a springboard for further research in organizational design within the education sector of extracurricular high school sport. Interconnections were found between the data associated with the external and internal contexts within which the extracurricular sport departments exist. The analysis of the internal context indicated the important role played by organizational members in shaping the context within which the departments exist. The analysis of the external context highlighted the institutional pressures that were present within the education environment. Both political and cultural expectations related to the role of extracurricular sport within schools were visible and were subsequently used by the high schools to create legitimacy and prestige, and to access resources.
    • Organizational commitment and perceived relatedness as correlates of the intention to continue officiating in track and field

      Gray, Casey.; Applied Health Sciences Program (Brock University, 2006-05-19)
      The objectives of the present study were to explore three components of organizational commitment (affective [AC], normative [NC] and continuance [CC] commitment; Allen & Meyer, 1991), perceived relatedness (Oeci & Ryan, 1985; 2002), and behavioural intention (Ajzen, 2002) within the context of volunteer track and field officiating. The objectives were examined in a 2-phase study. Ouring phase 1, experts (N = 10) with domain familiarity assessed the item content relevance and representation of modified organizational commitment (OC; Meyer, Allen & Smith, 1993) and perceived relatedness (La Guardia, Oeci, Ryan & Couchman, 2000) items. Fourteen of 26 (p < .05) items were relevant (Aiken's coefficient V) and NC (M = 3.88, SO = .64), CC (M = 3.63, SD = .52), and relatedness (M = 4.00, SD = .93) items had mean item content-representation ratings of either "good" or "very good" while AC (M = 2.50, SD = 0.58) was rated "fair". Participants in phase 2 (N = 80) responded to items measuring demographic variables, perceptions of OC to Athletics Canada, perceived relatedness to other track and field officials, and a measure of intention (yiu, Au & Tang, 2001) to continue officiating. Internal consistency reliability estimates (Cronbach's (1951) coefficient alpha) were as follows: (a) AC = .78, (b) CC = .85, (c) NC = .80 (d) perceived relatedness = .70 and, (e) intention = .92 in the present sample. Results suggest that the track and field officials felt only minimally committed to Athletics Canada (AC M = 3.90, SD = 1.23; NC M = 2.47, SD = 1.25; CC M = 3.32; SD = 1.34) and that their relationships with other track and field officials were strongly endorsed (M = 5.86, SD = 0.74). Bivariate correlations (Pearson r) indicated that perceived relatedness to other track and field officials demonstrated the strongest relationship with intention to continue officiating (r = .346, p < .05), while dimensions of OC were not significantly related to intention (all p's > .05). Together perceived relatedness (j3 = .339, p = .004), affective commitment (j3 = -.1 53, p = .308), normative commitment (j3 = -.024, p = .864) and continuance commitment (j3 = .186, P = .287) contribute to the prediction of intention to continued officiating (K = .139). These relationships remained unaffected by the inclusion of demographic (j3age = -.02; P years with Athletics Canada = -.13; bothp's > .05) or alternative commitment (j3sport = -.19; P role = .15; Pathletes = .20; all p' s > .05) considerations. Three open-ended questions elicited qualitative responses regarding participants' reasons for officiating. Responses reflecting initial reasons for officiating formed these higher order themes: convenience, helping reasons, extension of role, and intrinsic reasons. Responses reflecting reasons for continuing to officiate formed these higher order themes: track and field, to help, and personal benefits. Responses reflecting changes that would influence continued involvement were: political, organizational/structural, and personal. These results corroborate the findings of previous investigations which state that the reasons underpinning volunteer motivations change over time (Cuskelly et al., 2002). Overall, the results of this study suggest that track and field officials feel minimal commitment to the organization of Athletics Canada but a stronger bond with their fellow officials. Moreover, the degree to which track and field officials feel meaningfully connected to one another appears to exert a positive influence on their intentions to continue officiating. As such, it is suggested that in order to promote continued involvement, Athletics Canada increases its focus on fostering environments promoting positive interactions among officials.
    • The perception of mental toughness of student-athletes in their academic and sports domains

      Waters, Liam; Applied Health Sciences Program
      The purpose of this study was to investigate university student-athletes’ perceptions of mental toughness in both their sport and academic domains. This study took a general qualitative approach through a constructivist lens, to allow for student-athletes’ perceptions to shape the understanding of mental toughness. There were a total of 10 participants (3 male and 7 female student-athletes) interviewed from a variety of sports and academics programs. Thematic analysis was used to identify four main themes: the dynamic nature of mental toughness, outcomes of mental toughness, resilience, and relationships. Findings highlighted similarities and differences between sports and academics, that allow for a better understanding of mental toughness in general, specifically amongst this demographic. The theme “The dynamic nature of mental toughness” showed that mental toughness fluctuated within different environmental settings or with varying performance outcomes, but in general it improved over time. Outcomes of mental toughness refer to factors such as confidence that resulted when participants experienced high levels of mental toughness, and also included the pursuit and embrace of a challenge to compete at peak performance, staying consistent, and staying focused on the task. Resilience was mutually understood as an essential characteristic of mental toughness within both sports and academics, and was more pronounced amongst student-athletes when their mental toughness state was high. The theme of relationships was a unique finding that showed how personal and professional relationships contribute to mental toughness differently within sports compared to academics. Forming a personal relationship with a teammate/classmate outside of the direct sport/academic setting helped athletes with their mental toughness. Additionally, it helped form a stronger professional relationship within the respective domains as well, aiding their performance. Across all themes, mental toughness was more prominent in sports than academics, where student-athletes generally described mental toughness as playing a crucial role in their academics. In addition, results showed support for the unidimensional nature of mental toughness through its general applicability described by participants in both domains without restriction of different dimensions. Therefore, the findings of this study indicate that mental toughness is a crucial psychological resource for student-athletes within both sports and academics.
    • Personality traits and individual differences predict changes in postural control under conditions of height-induced postural threat

      Zaback, Martin; Applied Health Sciences Program (Brock University, 2014-09-05)
      This thesis explored whether individual characteristics could predict changes in postural control in young adults under conditions of height-induced postural threat. Eighty-two young adults completed questionnaires to assess trait anxiety, trait movement reinvestment, physical risk-taking, and previous experience with height-related activities. Tests of static (quiet standing) and anticipatory (rise to toes) postural control were completed under conditions of low and high postural threat manipulated through changes in surface height. Individual characteristics were able to significantly predict changes in static, but not anticipatory postural control. Trait movement reinvestment and physical risk-taking were the most influential predictors. Evidence was provided that changes in fear and physiological arousal mediated the relationship between physical risk-taking and changes in static postural control. These results suggest that individual characteristics shape the postural strategy employed under threatening conditions and may be important for clinicians to consider during balance assessment and treatment protocols.
    • A Phenomenological Approach to Exploring Body Image Among Powerlifters

      moretto, Joe; Applied Health Sciences Program
      Sport and exercise are associated with less negative body image and more positive body image. For example, athletes report less negative body image than exercisers and non-athletes. One explanation for this finding is that competitive sport may be an embodying activity. Embodying activities are those which promote a mind-body link, body awareness and responsiveness, and physical empowerment and competence which in turn may reduce self-objectification and promote more positive body image. Powerlifting, a sport that involves the squat, bench, and deadlift, meets the criteria for embodying activities. However, powerlifters also often have an appearance that does not ascribe to West culture ideal; in fact, they often have a body type that is perceived as obese (based on appearance). Ultimately, these athletes may experience body image struggles, as these athletes attempt to meet two contradictory ideals. Consequently, powerlifters’ experiences may be linked to both positive and negative body image, and further investigation is warranted. The research question for this study was: what are powerlifters’ experiences of body image in relation to their dietary and physical activity patterns? The research question was investigated using a phenomenological approach, specifically, heuristic inquiry. Four male and three female competitive powerlifters each participated in two semi-structured interviews. Interview questions aimed to understand the interconnection between body image, exercise, and dietary habits. Overall, results from this study provided evidence of both positive and negative body image. Women and men powerlifters embodied functionality (e.g., feeling their body lift the weight on the bar and focusing less on their how their body looked) and particularly for women, this represented a real shift in body image from their experiences prior to becoming involved in the sport. However, gender differences were also evident. Women related to the physical characteristics of the other powerlifters (e.g., toned and athletic female powerlifters) which impacted their body image both positively and negatively. Men sought powerlifting as a catalyst to not focus on the muscular ideal. Further, women’s dietary habits showed aspects of dietary restraint whereas men often force fed themselves to stay competitive. Overall, powerlifting had a complex impact on men and women’s body image.
    • Phosphorylation of Skeletal Muscle Pyruvate Dehydrogenase Phosphatase in Response to Insulin Stimulation

      Choptiany, Jonathan Robert; Applied Health Sciences Program (Brock University, 2013-08-01)
      Pyruvate dehydrogenase phosphatase (PDP) regulates carbohydrate oxidation through the pyruvate dehydrogenase (PDH) complex. PDP activates PDH, enabling increased carbohydrate flux towards oxidative energy production. In culture myoblasts, both PDP1 and PDP2 undergo covalent activation in response to insulin–stimulation by protein kinase C delta (PKCδ). Our objective was to examine the effect of insulin on PDP phosphorylation and PDH activation in skeletal muscle. Intact rat extensor digitorum longus muscles were incubated (oxygenated at 25°C, 1g of tension) for 30min in basal or insulin–stimulated (10 mU/mL) media. PDH activity increased 58% following stimulation, (p=0.057, n=11). Serine phosphorylation of PDP1 (p=0.047) and PDP2 (p=0.006) increased by 29% and 48%, respectively (n=8), and mitochondrial PKCδ protein content was enriched by 45% in response to stimulation (p=0.0009, n=8). These data suggest that the insulin–stimulated increase in PDH activity in whole tissue is mediated through mitochondrial migration of PKCδ and subsequent PDP phosphorylation.
    • A physical activity intervention in a workplace setting

      Francoeur, Chera.; Applied Health Sciences Program (Brock University, 2006-05-19)
      Physical inactivity poses a huge burden on Canada's health care system and is detrimental to the health of Canadians (Katzmarzyk & Janssen, 2004). Walking is a viable option for individuals to become physically active on a daily basis and is in fact the most commonly reported leisure time physical activity. It has been associated with many health benefits including weight loss/weight control, reduced risk of coronary artery disease and diabetes, lowered blood pressure, and improved psychological wellbeing (Brisson & Tudor-Locke, 2004). Specifically, individuals' stage of change, selfefficacy and health related quality of life (HRQL) are three psychological constructs that can be greatly improved with increased physical activity (Dishman, 1991; Penedo & Dahn, 2005; Poag & McAuley, 1992). Public health physical activity recommendations exist but many individuals find these difficult to meet due to overly busy lifestyles (Public Health Agency of Canada, 2003). Pedometers are inexpensive devices that can monitor individual bouts of walking so that the incorporation of physical activity into one's daily life is more plausible. They are also excellent tools for motivation, goalsetting, and immediate feedback (Brisson & Tudor-Locke, 2004). Since many people spend a large proportion of their time at their places of employment, workplaces have begun to be a common site for the development of physical activity interventions. These programs have been growing in popUlarity and have shown numerous benefits for both employees and employers (Voit, 2001). The purpose of the current study was to implement and evaluate the use of a pedometer-based physical activity intervention incorporating goal-setting and physical activity logs in a workplace setting, and to examine the relationship between different types of self-efficacy (task, barrier, and scheduling) and different phases of the intervention. Twenty male participants from a local steel manufacturing plant who exhibited health risk factors (e.g. hypertension, diabetes, etc.) were assigned to one of two groups (group A or group B). All participants were asked to wear pedometers on their waists, record their daily steps, set goals that were outlined on a step-tracking sheet (detennined by their baseline number of steps), and keep track of their work days, wakelbed time, sedentary time, and time spent doing other physical activity. Group A began the intervention immediately following the baseline measures, whereas group B continued with their regular routine for 4 weeks before beginning. Physiological measures (height, weight, blood pressure, relative body fat, waist and hip circumference, and body mass index) were taken and a battery of questionnaires that assessed barrier, task and scheduling self-efficacy, HRQL, and stage of change administered at baseline, week 5 (end of intervention for group A), week 9 (end of intervention for group B; follow-up for group A) and week 13 (follow-up for both groups). Results showed that this workplace physical activity intervention was successful at increasing the participants' daily steps, that task self-efficacy is a significant predictor of participants' exercise adherence during the initial stages of participation (intervention phase), and that the participants felt that this intervention was effective. Finally, further exploratory analyses showed that this intervention was effective for all participants, but most valuable for participants most in need of improvement - that is, those who were most sedentary prior to the intervention. This intervention is an inexpensive use of simple and effective tools (e.g. pedometers), has the potential to attract a wide variety of participants and become a pennanent part of any health promotion initiative.
    • Physical activity of children with developmental coordination disorder in the presence of attention deficit hyperactivity disorder : does gender matter?

      Baerg, Sally; Applied Health Sciences Program (Brock University, 2009-02-01)
      Baerg, S., Cairney, J., Hay, J., Rempel, L. and Faught, B.E. (2009). Physical Activity of Children with Developmental Coordination Disorder in the Presence of Attention Deficit Hyperactivity Disorder: Does Gender Matter? Brock University, St. Catharines, Ontario, CANADA. Children with Developmental Coordination Disorder (DCD) have difficulties in motor coordination. Attention-deficit hyperactive disorder (ADHD) is considered the condition most co-morbid with DCD at approximately 50%. Children with DCD are generally less physically active (PA) than their peers, while children with ADHD are often considered more physically active. It is not known if the physical activity patterns of children with DCD-ADHD resemble those of children with primarily DCD or that of their healthy peers. The primary objective of this research was to contrast physical activity patterns between children with DCD, DCD-ADHD, and healthy controls. Since boys are generally reported as more physically active than girls, a secondary objective was to determine if gender moderated the association between groups and physical activity. A sample of males (n=66) and females (n=44) were recruited from the Physical Health Activity Study Team (PHAST) longitudinal study. The Movement Assessment Battery for Children (2nd Ed.) was used to identify probable cases of DCD, and Connor's Revised Parent Rating Scale- Short Version to identify ADHD. Subjects (mean age=12.8±.4 yrs) were allocated to three groups; DCD (n=32), DCD-ADHD (n=30) and control (n=48). Physical activity was monitored for seven days with the Actical® accelerometer (activity count, step count and energy expenditure). Children completed the Participation Questionnaire (PQ) during the in-school session of data collection for the PHAST study. Height, weight and body mass index (BMI) were also determined. Analysis of variance showed significant group differences for activity count (F(2,56)=5.36, p=.007) and PQ (F(2,44 )=6. 71, p=.003) in males, while a significant group difference for step count (F(2,37)=3.55, p=.04) was found in females. Post hoc comparison tests (Tukey) identified significantly lower PQ and activity count between males with OCD and controls (p=.004) and males with DCD-ADHD and controls (p=.003). Conversely, females with DCD-ADHD had significantly more step counts than their controls (p=.01). Analysis of covariance demonstrated a gender by DCD groups negative interaction for males (activity count) (F(2,92):;:3.11, p=.049) and a positive interaction for females (step count) (F(1,92)=4.92, p=.009). Hyperactivity in females with DCD-ADHD appears to contribute to more physical activity, whereas DCD may contribute to decreased activity in males with DCD and DCDADHD. Further research is needed to examine gender differences in physical activity within the context of DCD and ADHD.
    • Physical training, inflammation and bone integrity in elite female rowers

      Kurgan, Nigel; Applied Health Sciences Program
      This study examined whether fluctuations in training load during an Olympic year lead to changes in mineral properties and factors that regulate bone (sclerostin (SOST), osteoprotegerin (OPG)), and receptor activator of nuclear factor kappa-B ligand (RANKL)) and energy metabolism (insulin-like growth factor-1 (IGF-1) and leptin), and inflammation (tumor necrosis factor-α (TNF-α)) in elite heavyweight female rowers. Blood samples were drawn from female heavy-weight rowers (n=15) (27.0±0.8y, 80.9±1.3 kg, 179.4±1.4 cm) at baseline (T1 – 45 weeks pre-Olympic Games) and following 7, 9, 20, 25 and 42 weeks (T1-6, respectively). Serum was analyzed by Multiplex assays (EMD Millipore, Toronto, CAN). Total weekly training load was recorded over the weeks prior to each time point. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry at T1 and T6. Total BMD increased significantly pre- to post-training (+1.6%). OPG, IGF-1, and leptin were not different across all time points. OPG/RANKL was significantly higher at both T4 and 5 compared to T1 and 2. High training load (T5) was associated with the highest TNF-α levels (2.1 pg/ml), and a parallel increase in SOST (993.1 pg/ml), while low training load (T6 - recovery) was associated with significantly lower TNF-α (1.5 pg/ml) and a parallel decrease in SOST (741.0 pg/ml). Leptin was a significant determinant of bone-mineral properties in these athletes. These results suggest exercise training can lead to an increase in OPG/RANKL, and training load periodization can control the inflammatory response associated with intense training, and combined with adequate caloric intake can preserve bone mineral integrity in elite female athletes.
    • Positive Body Image and Physical Activity in Pregnant Women

      angrish, kirina; Applied Health Sciences Program
      Generally, research has shown pregnant women have a more negative body image pre-pregnancy and early pregnancy compared to mid-to-late pregnancy. Negative body image in this population has been linked to several important pregnancy-related behaviours and poorer mental health that may put the mother’s and baby’s health at risk. In regards to positive body image, there has been a lack of research investigating how positive body image constructs such as body appreciation and embodiment change, and little work has examined how self-objectification changes. In nonpregnant populations, positive body image has been linked to several health behaviours and outcome; thus, it is important to determine if pregnant women experience positive body image during their pregnancy. In addition, participation in physical activity has been linked to improvements in body image via an increase in embodiment and a decrease in selfobjectification in young adult women. Whether this is true for the pregnant population is unknown. The overall purpose of this study was to understand the relationship between positive body image and physical activity in pregnant women. The first purpose was to determine whether body appreciation, embodiment, and self-objectification levels differ across trimester. The second purpose was to determine if physical activity was associated with body appreciation, and if this relationship was mediated by an increase in embodiment and a decrease in selfobjectification. Thirty-one women in the first trimester, 55 in the second trimester, and 75 in the third trimester completed measures of body appreciation, embodiment, self-objectification, and physical activity online. Multivariate analysis of covariance showed all measures differed by trimester. Post-hoc tests showed body appreciation (M = 3.79; SE = 0.08) and embodiment (M = 2.92; SE = 0.05) were higher and self-objectification (M = 3.86; SE = 0.14) lower in third trimester compared to first trimester (M = 3.37; SE = 0.12; M = 2.56; SE = 0.09; M = 4.54; SE = 0.22). Embodiment was also higher in the third trimester (M = 2.92; SE = 0.05) compared to the second trimester (M = 2.67; SE = 0.06). Serial mediation analysis revealed physical activity was associated with body appreciation through an increase in embodiment and a decrease in self-objectification. The findings from this study indicate positive body image improves across pregnancy and physical activity could be one way to improve positive body image in pregnant women.
    • Predicting the Risk of Lung Cancer in Never-smokers

      Thompson, Cameron; Applied Health Sciences Program
      Despite being considered a disease of smokers, approximately 10-15% of lung cancer cases occur in never-smokers. Lung cancer risk prediction models have demonstrated excellent ability to discriminate cases from non-cases, and have been shown to be more efficient at selecting individuals for future screening than current criteria. Existing models have primarily been developed in populations of smokers, thus there was a need to develop an accurate model in never-smokers. This study focused on developing and validating a model using never-smokers from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Cox regression analysis, with six-year follow-up, was used for model building. Predictors included: age, body mass index, education level, personal history of cancer, family history of lung cancer, previous chest X-ray, and secondhand smoke exposure. This model achieved fair discrimination (optimism corrected c-statistic = 0.6645) and good calibration. This represents an improvement on existing neversmoker models, but is not suitable for individual-level risk prediction.
    • Preliminary epidemiological study of latent tuberculosis in Mexican agricultural workers in the Niagara region, Canada

      Duarte, Angela.; Applied Health Sciences Program (Brock University, 2008-06-29)
      It is well documented that the majority of Tuberculosis (TB) cases diagnosed in Canada are related to foreign-bom persons from TB high-burden countries. The Canadian seasonal agricultural workers program (SAWP) operating with Mexico allows migrant workers to enter the country with a temporary work permit for up to 8 months. Preiimnigration screening of these workers by both clinical examination and chest X-ray (CXR) reduces the risk of introducing cases of active pulmonary TB to Canada, but screening for latent TB (LTBI) is not routinely done. Studies carried out in industrialized nations with high immigration from TBendemic countries provide data of lifetime LTBI reactivation of around 10% but little is known about reactivation rates within TB-endemic countries where new infections (or reinfections) may be impossible to distinguish from reactivation. Migrant populations like the SAWP workers who spend considerable amounts of time in both Canada and TBendemic rural areas in Mexico are a unique population in terms of TB epidemiology. However, to our knowledge no studies have been undertaken to explore either the existence of LTBI among Mexican workers, the probability of reactivation or the workers' exposure to TB cases while back in their communities before returning the following season. Being aware of their LTBI status may help workers to exercise healthy behaviours to avoid TB reactivation and therefore continue to access the SAWP. In order to assess the prevalence of LTBI and associated risk factors among Mexican migrant workers a preliminary cross sectional study was designed to involve a convenience sample of the Niagara Region's Mexican workers in 2007. Research ethics clearance was granted by Brock University. Individual questionnaires were administered to collect socio-demographic and TB-related epidemiological data as well as TB knowledge and awareness levels. Cellular immunity to M tuberculosis was assessed by both an Interferon-y release assay (lGRA), QuantiFERON -TB Gold In-Tube (QFf™) and by the tuberculin skin test (TSn using Mantoux. A total of 82 Mexican workers (out of 125 invited) completed the study. Most participants were male (80%) and their age ranged from 22 to 65 years (mean 38.5). The prevalence of LTBI was 34% using TST and 18% using QFTTM. As previously reported, TST (using ~lOmm cut-off) showed a sensitivity of 93.3% and a specificity of 79.1 %. These findings at the moment cannot predict the probability of progression to active TB; only longitudinal cohort studies of this population can ascertain this outcome. However, based on recent publications, lORA positive individuals may have up to 14% probability of reactivation within the next two years. Although according to the SA WP guidelines, all workers undergo TB screening before entering or re-entering Canada, CXR examination requirements showed to be inconsistent for this population: whereas 100% of the workers coming to Canada for the first time reported having the procedure done, only 31 % of returning participants reported having had a CXR in the past year. None of the participants reported ever having a CXR compatible with TB which was consistent with the fact that none had ever been diagnosed with active pulmonary TB and with only 3.6% reporting close contact with a person with active TB in their lifetime. Although Mexico reports that 99% of popUlation is fully immunized against TB within the first year of age, only 85.3% of participants reported receiving BOC vaccine in childhood. Conversely, even when TST is not part of the routine TB screening in endemic countries, a suqDrisingly high 25.6% reported receiving a TST in the past. In regards to TB knowledge and awareness, 74% of the studied population had previous knowledge about (active) TB, 42% correctly identified active TB symptomatology, 4.8% identified the correct route of transmission, 4.8% knew about the existence of LTBI, 3.6% knew that latent TB could reactivate and 48% recognized TB as treatable and curable. Of all variables explored as potential risk factors for LTBI, age was the only one which showed statistical significance. Significant associations could not be proven for other known variables (such as sex, TB contact, history of TB) probably because of the small sample size and the homogeneity of the sample. Screening for LTBI by TST (high sensitivity) followed by confirmation with QFT''"'^ (high specificity) suggests to be a good strategy especially for immigrants from TB high-burden countries. After educational sessions, workers positive for LTBI gained greater knowledge about the signs and symptoms of TB reactivation as well as the risk factors commonly associated with reactivation. Additionally, they were more likely to attend their annual health check up and request a CXR exam to monitor for TB reactivation.

      Stegne, Marina; Applied Health Sciences Program (Brock University, 2011-09-09)
      This thesis describes an ancillary project to the Early Diagnosis of Mesothelioma and Lung Cancer in Prior Asbestos Workers study and was conducted to determine the effects of asbestos exposure, pulmonary function and cigarette smoking in the prediction of pulmonary fibrosis. 613 workers who were occupationally exposed to asbestos for an average of 25.9 (SD=14.69) years were sampled from Sarnia, Ontario. A structured questionnaire was administered during a face-to-face interview along with a low-dose computed tomography (LDCT) of the thorax. Of them, 65 workers (10.7%, 95%CI 8.12—12.24) had LDCT-detected pulmonary fibrosis. The model predicting fibrosis included the variables age, smoking (dichotomized), post FVC % splines and post- FEV1% splines. This model had a receiver operator characteristic area under the curve of 0.738. The calibration of the model was evaluated with R statistical program and the bootstrap optimism-corrected calibration slope was 0.692. Thus, our model demonstrated moderate predictive performance.
    • Prevalence of overweight and obesity in children from urban and rural Niagara

      Duncan, Kristy D. M.; Applied Health Sciences Program (Brock University, 2006-06-15)
      Purpose: The influence of environment in the development of overweight and obesity is an ongoing concern. This investigation examined the influence of urbanization on the rates of childhood overweight and obesity. Method: 2167 (1090M, 1077F) grade four children from 75 schools in Ontario's Niagara Region were sampled. A sophisticated algorithm overlaying electoral boundaries, population densities, and the knowledge of community members was used to classify schools into one of three location categories: urban {N= 1588), urban fringe {N= 379), and rural (A^= 234). Each subject was measured for: height, weight, and aerobic performance (Leger). Physical activity was evaluated with the self-report Participation Questionnaire (free-time and organized sport activities), and teacher's evaluations of student activity. Overweight (overweight and obesity combined) was measured both as a continuous (BMI) and categorical variable (BMI category), to evaluate the prevalence by location. A multivariate analysis was used to test for a suppression effect. Results: BMI and BMI category did not differ significantly by location or gender, and no evidence of a gender interaction existed. According to both a linear and logistic regression, physical activity or fitness levels did not suppress the influence of location on BMI and BMI category. Age, gender, free-time activity, organized sports, fitness level, and number of siblings, were all found to significantly influence overweight. Conclusions: It is plausible that the prevalence of overweight does not differ in urban and rural children from the Niagara Region. Further investigation is recommended, examining subjects by individual location of residence, in multiple regions throughout Ontario.
    • A Principal Component Analysis Comparing Forward Skating Strides Pre-Post Skate Treadmill Training in Youth Hockey Players

      Iantomasi, Vincent; Applied Health Sciences Program
      The purpose of the study was to explore temporal and phasic waveform patterns within kinematic data, obtained from forward skating strides, pre-post skate treadmill training in youth (U-11), male hockey players to investigate changes in kinematics. Continuous joint angle (deg) and angular velocity (deg/s) stride data for the trunk, hip, and knee were determined, time normalized, and averaged. PCA results suggested that most of the pre-post variance in skating mechanics could be explained through an increase in joint angle (deg) and angular velocity (deg/s) magnitudes during the propulsive and recovery phases of the stride cycle. Single component reconstruction (SCR) facilitated visual representation and interpretation of kinematic differences by isolating variances within each principal component and reconstructing lower (5th percentile) and upper (95th percentile) waveforms based on the respective scalar weight factor of PC scores. Post-training, SCR suggested patterns of increased trunk extension throughout the stride cycle, increased hip and knee extension during propulsion, and increased hip and knee flexion during recovery. Statistical parametric mapping (SPM) statistically analysed continuous data points across two waveforms. SPM revealed significant differences in pre-post trunk flexion and extension magnitudes from the early glide phase to propulsion onset ([p=0.0023], ~0-20% stride cycle) and from late propulsion to weight acceptance ([p=0.0001], ~40-80% stride cycle). Differences in pre-post hip and knee measures were non-significant (p>0.05). PCA, SCR and SPM analyses have the potential to contribute to our understanding of biomechanical training adaptations in stride mechanics in youth ice hockey players.
    • PROJECT K.T.A.P.E.: Kinesiology Tape for Athlete Performance

      Santin, Sydney Alexandria; Applied Health Sciences Program
      Kinesiology Tape (KT) is used to prevent or rehabilitate sports injuries, as well as to enhance an athlete’s performance. The primary aim of this study was to examine differences between athletes who use KT and athletes who do not use KT using an extended Theory of Planned Behaviour (TPB) framework that included autonomous and controlled motivation for KT use. The secondary aims of this study were to (a) determine if KT is prevalent among competitive/recreational athletes, and (b) identify the reasons why athletes report using KT. Data was collected from a purposive sample of competitive/recreational athletes, using non-experimental (cross-sectional) design. Participants (n = 127) completed a questionnaire modified to fit the aims of this study using a secure online interface (www.surveymonkey.com). Multivariate Analyses of Variance indicated that athletes who used KT in the past 12 months reported higher subjective norms, perceived behavioural control, attitudes, intentions and autonomous motives, than athletes who did not use KT. Approximately half of the sample (49.6%) reported using KT in the past 12 months, and ‘rehabilitation’ was the main reason KT was used. Overall, the results of this study suggest a greater understanding of the psychological variables that may influence an athlete to use KT in sport. The results of this study support the use of the extended TPB in the context of understanding an athletes KT behaviours.