• Identification of Network-Based Risk Factors Associated with Gonorrhea

      Zahradnik, Michelle; Applied Health Sciences Program
      The evolving antimicrobial resistance coupled with a recent increase in incidence highlights the importance of reducing gonococcal transmission. Establishing novel risk factors associated with gonorrhea facilitates the development of appropriate prevention and disease control strategies. Sexual Network Analysis (NA), a novel research technique used to further understand sexually transmitted infections, was used to identify network-based risk factors in a defined region in Ontario, Canada experiencing an increase in the incidence of gonorrhea. Linear network structures were identified as important reservoirs of gonococcal transmission. Additionally, a significant association between a central network position and gonorrhea was observed. The central participants were more likely to be younger, report a greater number of risk factors, engage in anonymous sex, have multiple sex partners in the past six months and have sex with the same sex. The network-based risk factors identified through sexual NA, serving as a method of analyzing local surveillance data, support the development of strategies aimed at reducing gonococcal spread.
    • Identifying changes in dietary intake, diet quality, body weight and body composition during first year university

      Beaudry, Kayleigh; Applied Health Sciences Program
      The purpose of this study was to identify if dietary intake and eating habits change in students during first-year university and how these changes influence anthropometrics and body composition. 301 students (n=71 males, n=230 females) completed food frequency and dietary habits questionnaires. Anthropometry and body composition were measured at the beginning and end of first-year university. Both males and females gained body weight (p<0.05). Both gained fat mass and males gained significantly more lean mass than females. Energy intake significantly decreased by ~400 kcals/d for both sexes. Diet quality also decreased in both sexes characterized by negative changes in healthy and unhealthy foods. Caffeine intake remained the same and alcohol intake increased. Therefore, modest weight gain does occur during first-year university, males more than females, but the composition was different. Dietary intake and quality decreased in both sexes and changes in some dietary habits reflected these negative intake changes.
    • Identifying Changes in Physical Activity Behaviours That Lead to Weight Gain in First Year University Students

      Thomas, Aysha Martinah; Applied Health Sciences Program
      The transition to university is a critical time period for weight gain, possibly explained by a decrease in physical activity. The aim of this study was to identify changes in physical activity as students’ transition from high school to university and to assess if they relate to body weight and composition. Three hundred one (71 males, 230 females) first year Brock University students participated. Anthropometric and body composition data were collected in September and April. Students also filled out questionnaires assessing their physical activity behaviours. Significant increases in weight, BMI, and body composition were observed across the sample, accompanied by reductions in physical activity output and increases in factors preventing physical activity participation. However, the reductions in physical activity were not correlated with the changes in body composition. Therefore, in our sample, changes in physical activity behaviours are not the main cause of weight gain in first year university students.
    • Imagery or video feedback : which is the "route" to strategic improvement?

      Brownell, Kyle J.; Applied Health Sciences Program (Brock University, 2003-07-09)
      The implementation of imagery and video feedback programs has become an important tool for aiding athletes in achieving peak performance (Halliwell, 1990). The purpose of the study was to determine the effect of strategic imagery training and video feedback on immediate performance. Participants were two university goaltenders. An alternating treatment design (ATD; Barlow & Hayes, 1979; Tawney & Gast, 1984) was employed. The strategies were investigated using three plays originating from the right side by a right-handed shooting defenceman from the blueline. The baseline condition consisted of six practices and was used to establish a stable and "ideal" measure of performance. The intervention conditions included alternating the use of strategic imagery (Cognitive general; Paivio, 1985) and video feedback. Both participants demonstrated an increase in the frequency of Cognitive general use. Specific and global performance measures were assessed to determine the relative effectiveness of the interventions. Poor inter-rater reliability resulted in the elimination of specific performance measures. Consequently, only the global measure (i.e., save percentage) was used in subsequent analyses. Visual inspection of participant save percentage was conducted to determine the benefits of the intervention. Strategic imagery training resulted in performance improvements for both participants. Video feedback facilitated performance for Participant 2, but not Participant 1. Results are discussed with respect to imagery and video interventions and the challenges associated with applied research. KEYWORDS: imagery, video, goaltenders, alternating treatment design.
    • Immunoendocrine profiles in neurocysticercosis patients: a clinical study in Honduras

      Gadea, Nicholas; Applied Health Sciences Program
      Neurocysticercosis (NCC) is a parasitic infection caused by the infiltration and localization of the larval stage of the tapeworm Taenia solium within the central nervous system (CNS). Clinical presentation and severity are heterogeneous and depend particularly on the age and sex of its host. A clinical study was conducted to evaluate specific endocrine and immune status changes that are associated with NCC. A total of 11 (9 female and 2 male) NCC patients were recruited and matched by sex and age with 11 healthy subjects. Evaluations for 7 hormones and 2 cytokines were measured and compared between patients and their matched controls. Compared with controls, all patients had statistically significant higher serum concentration levels of 17β-estradiol (E2), progesterone (P4), androstenedione (A4), luteinising hormone (LH), follicle stimulating hormone (FSH), interleukin-6 (IL-6), and interleukin-10 (IL-10). In contrast, NCC patients showed significantly lower concentrations of free testosterone (T4), and dihydrotestosterone (DHT). To our knowledge, the present study constitutes one of the first demonstrations in humans that the presence of T. solium metacestodes can modify the host microenviornment by the induction of immunoendocrine changes. In summary, the present work adds to the growing body of knowledge indicating how this parasitic infection may modulate the host for its successful establishment and survival. In addition to being “curiosity-driven”, the ultimate aim of this type of work is to provide insight into the design of new therapeutic strategies. Among these, researchers in the field envision novel treatments or vaccines with the ability to block specific parasite molecules, thereby inhibiting the cysticercus establishment in the CNS, or at least shortening its survival and improving the pathological markers associated with neurocysticercosis.
    • The Impact of Directed Mirror Focus and Technique Cues on Psychological, Cognitive and Emotional Exercise Correlates in an Introductory Weight Training Orientation

      Cameron, Carly; Applied Health Sciences Program
      The purpose of the study was to investigate whether teaching inactive and low active women to use mirrors for form and technique purposes could lessen the negative impact of mirrors on self-presentational concerns, affect, and self-efficacy. Eligible women (N = 82) underwent a one-on-one weight training orientation with a personal trainer. Participants were randomized into one of four experimental groups, each unique in the type of feedback (general or technique-specific) and the degree of focus on the mirror for technique reinforcement. Questionnaires assessed study outcomes pre- and post-orientation. Results indicated groups did not significantly differ on any post-condition variables, when controlling for pre-condition values (all p’s >.05). All groups showed outcome improvements following the orientation. This suggests that during a complex task, a personal trainer who emphasizes form and technique can facilitate improvements to psychological outcomes in novice exercisers, independent of the presence of mirrors or directional cues provided.
    • The impact of drug-induced dyskinesias on rapid alternating movements in patients with Parkinson's disease

      Ghassemi, Mehrdad Marco.; Applied Health Sciences Program (Brock University, 2005-06-15)
      We investigated the likelihood that hypokinesia/bradykinesia coexist with druginduced dyskinesias (DID) in patients with Parkinson's disease (PD). The influence of dyskinesias on rapid alternating movements (RAM) was investigated in ten dyskinetic patients (DPD). Their motor performance was compared to that of ten age/gendermatched non-dyskinetic patients (NDPD) and ten healthy control subjects. Whole-body magnitude (WBM) and fast pronation-supination at the wrist were recorded using 6- degrees of freedom magnetic motion tracker and forearm rotational sensors, respectively. Subjects were asked to pronate-supinate their dominant hand for 10s. Pre- and postmeasures were taken in a neutral position for 20s. RANGE (measure of hypokinesia), DURATION (measure of bradykinesia). VELOCITY (measure of bradykinesia) and IRREGULARITY (measure of fluctuations in movement amplitude) were used to assess RAM performance. Results showed that DPD patients had greater WBM than NDPD and control groups during rest and RAM performance. There were no differences in performance between NDPD and DPD groups for RANGE, DURATION and VELOCITY, despite significant longer disease duration for the DPD group (DPD = 15.5 ± 6.2 years versus NDPD = 6.6 ± 2.6 years). However, both the NDPD and DPD groups showed lower RANGE, longer DURATION, and reduced VELOCITY compared to controls,, suggesting the presence of bradykinesia and hypokinesia. In the case of IRREGULARITY, DPD patients showed clear fluctuations in movement amplitude compared to the NDPD and control groups. However, the lack of correlation between WBM and IRREGULARITY within the DPD group (Spearman's rank order, Rho - 0.31, p > 0.05), suggests that DID was not the primary cause of the fluctuating movementamplitude observed in that group. In conclusion, these findings suggest that DID may coexists with bradykinesia and hypokinesia, but that they are not inevitably accompanied with worsening motor performance.
    • The impact of job insecurity on mental health over time across gender and family responsibility

      Kaur, Sukhdeep; Applied Health Sciences Program
      While there is growing evidence that job insecurity leads to increased mental distress, prior studies have not investigated how gender and parental responsibilities may exacerbate this relationship. Since gender and parental responsibilities may interact with job insecurity to produce unique stressors, examining their contribution as potential effect modifiers may provide insights into gender inequalities in mental health and inform gender-sensitive labour policies to ameliorate the negative effects of job insecurity. Our study addresses this gap by examining the longitudinal association between job insecurity and mental health across different configurations of gender and parental responsibilities using a prospective cohort study design. Our sample includes 34,772 employed participants from the UK Household Longitudinal Study over the period of 2010-2018. A gender-stratified fixed-effect regression was used to model the within-person change over time in mental health functioning associated with loss of job security, and effect modification by parent-partner status (e.g. non-parents, lone mother, partnered father, etc). Loss of job security was associated with a moderate decrease in mental functioning for partnered fathers, partnered mothers, and non-parents ranging between a reduction in MCS-12 by 1.00 to 2.27 points (all significant at p<0.05). Lone fathers who lose their job security experienced a much higher decrease in mental functioning at -7.69 MCS-12 (95% CI: -12.69 to -2.70), while lone mothers did not experience any change. The effects of job insecurity on mental functioning varies across different configurations of gender, parental responsibilities, and partner status. Future studies should investigate the effects of policies that may reduce mental distress in the face of the threat of job loss such as reducing wait time for payment of unemployment benefits or increasing childcare cost coverage in the UK universal credit programme.
    • The Impact of Motor Task Success on the Perception of Target Size

      Bianchi, Krystina; Applied Health Sciences Program
      The action-specific perception literature has demonstrated that superior task success is correlated with perceiving task-related objects as appearing larger. Using a putting task, the present study examined this relationship under three different practice conditions (errorless, errorful, and self-control) while perceiving the size of the putting hole at various distances from the putting hole (25 cm, 50 cm, 75 cm, 100 cm, 125 cm, 150 cm, 175 cm, 200 cm). The acquisition and retention data revealed that there was no correlation between superior task success and larger perceived putting hole sizes. Additionally, it was found that the perceived putting hole sizes that were recorded at the end of acquisition were robust enough to persist over a 24-hour retention interval to exist before the first trial of retention. The results of the present study introduce inconsistencies with the current action-specific literature, while adding a novel contribution to the literature regarding perception retention.
    • The impact of social competence between physical activity and motor performance

      Martin, Britney; Applied Health Sciences Program (Brock University, 2013-04-18)
      Objective: To identify the association of low physical activity (PA) participation in children with various motor performances (MP) and to establish the impact of social competence (SC). Methods: Sixth grade children from PHAST study at Brock University (n=1958; 50.53% males) had MP test results from Bruininks-Oseretsky Test of Motor Proficiency, Participation Questionnaire (PQ) used for PA and Harter Social Competence Scale for self-perceived SC. Comparative tests, multiple and logistic regressions were performed. Results: Significant differences in PQ measures in MP quartiles and SCs. MP and SC are independent predictors of PA (p<.05) except with SES on free play activity, making MP not significant. Lower MP increased the odds of low total PA and organized sport participation but not for free play activities (OR~1). Higher SC reduced the risk of low participation in all PA measures. Conclusions: SC improves PA participation, including free play and organized sports, despite the child’s MP.
    • The impact of tobacco control policies on university students' smoking in Ontario

      Dupuis, Sandy.; Applied Health Sciences Program (Brock University, 2007-11-04)
      Objective. Despite steady declines in the prevalence of tobacco use among Canadians, young adult tobacco use has remained stubbornly high over the past two decades (CTUMS, 2005a). Currently in Ontario, young adults have the highest proportion of smokers of all age cohorts at 26%. A growing body of evidence shows that smoking restrictions and other tobacco control policies can reduce tobacco use and consumption among adults and deter initiation among youth; whether young adult university students' smoking participation is influenced by community smoking restrictions, campus tobacco control policies or both remains an empirical question. The purpose of this study is to examine the relationship among current smoking status of students on university campuses across Ontario and various tobacco control policies, 3including clean air bylaws of students' home towns, clean air by-laws of the community where the university is situated, and campus policies. Methods. Two data sets were used. The 200512006 Tobacco Use in a Representative Sample of Post-Secondary Students data set provides information about the tobacco use of 10,600 students from 23 universities and colleges across Ontario. Data screening for this study reduced the sample to 5,114 17-to-24 year old undergraduate students from nine universities. The second data set is researcher-generated and includes information about strength and duration of, and students' exposure to home town, local and campus tobacco control policies. Municipal by-laws (of students' home towns and university towns) were categorized as weak, moderate or strong based on criteria set out in the Ontario Municipal By-law Report; campus policies were categorized in a roughly parallel fashion. Durations of municipal and campus policies were calculated; and length of students' exposure to the policies was estimated (all in months). Multinomial logistic regression analyses were used to examine the relationship between students' current smoking status (daily, less-than-daily, never-smokers) and the following policy measures: strength of, duration of, and students' exposure to campus policy; strength of, duration of, and students' exposure to the by-law in the university town; and, strength of, duration of, and students' exposure to the by-law in the home town they grew up in. Sociodemographic variables were controlled for. Results. Among the Ontario university students surveyed, 7.0% currently use tobacco daily and 15.4% use tobacco less-than-daily. The proportions of students experiencing strong tobacco control policies in their home town, the community in which their university is located and at their current university were 33.9%,64.1 %, and 31.3% respectively. However, 13.7% of students attended a university that had a weak campus policy. Multinomial logistic regressions suggested current smoking status was associated with university town by-law strength, home town by-law strength and the strength of the campus tobacco control policy. In the fmal model, after controlling for sociodemographic factors, a strong by-law in the university town and a strong by-law in students' home town were associated with reduced odds of being both a less-than-daily (OR = 0.64, 95%CI: 0.48-0.86; OR = 0.80, 95%CI: 0.66-0.95) and daily smoker (OR = 0.59, 95%CI: 0.39-0.89; OR = 0.76, 95%CI: 0.58-0.99), while a weak campus tobacco control policy was associated with higher odds of being a daily smoker (OR = 2.08, 95%CI: 1.31-3.30) (but unrelated to less-than-daily smoking). Longer exposure to the municipal by-law (OR = 0.93; 95%CI: 0.90-0.96) was also related to smoking status. Conclusions. Students' smoking prevalence was associated with the strength of the restrictions in university, and with campus-specific tobacco control policies. Lessthan- daily smoking was not as strongly associated with policy measures as daily smoking was. University campuses may wish to adopt more progressive campus policies and support clean air restrictions in the broader community. More research is needed to determine the direction of influence between tobacco control policies and students' smoking.
    • Impacts of the COVID-19 Pandemic on Body Mass, Physical Activity and Nutrition in Canadian Post-Secondary Students

      Bell, Madison; Applied Health Sciences Program
      This study examined changes in body mass, physical activity, and dietary intake and habits in Canadian university students during the first (March – September 2020) and second (October 2020 – March 2021) lockdown/restrictions of the COVID-19 pandemic. Two observational, self-reported recall surveys were conducted online; in September 2020 (T1) and March 2021 (T2). Five hundred ten (99 males, 411 females) students completed the survey at T1 and 135 of them also completed the survey at T2. The surveys included demographic information (age, sex, living arrangements, activity level, etc.), body mass and height, and a series of standardized questionnaires on eating habits and behaviours, as well as energy, macronutrient, and micronutrient intake. Body mass and body mass index increased in both males and females. Body mass increased on average by 0.91 kg, t(132) = -2.7, p = 0.008, 95%CI = [0.24, 1.58]. Importantly, a significant change was shown that between T1 and T2 with a greater number of participants identified as overweight (19.8% to 24.4%) than normal weight (61.7% to 54.8%). Body mass change was not associated with changes in physical activity and dietary intake. Females were more likely to decrease At Home Workouts compared to males with no other significant changes detected for type of physical activity in either T1 or T2. Energy intake significantly decreased by ~200 kcals/d. Diet quality also changed in both sexes characterized by negative changes in in both macro and micronutrients. Restrictive eating behaviours were found to increase significantly in females and were more frequent in those with eating disorders. Therefore, modest weight gain did occur during the pandemic in Canadian university students despite the insignificant changes reported in physical activity and the decrease in overall dietary intake, which can be possibly attributed to the changes in diet quality and dietary behaviours.
    • Implementing the OPTIMAL model : the impact on students' motivation in an elementary school games environment

      Sheppard, Joanna C.; Applied Health Sciences Program (Brock University, 2005-05-21)
      Optimal challenge occurs when an individual perceives the challenge of the task to be equaled or matched by his or her own skill level (Csikszentmihalyi, 1990). The purpose of this study was to test the impact of the OPTIMAL model on physical education students' motivation and perceptions of optimal challenge across four games categories (i. e. target, batting/fielding, net/wall, invasion). Enjoyment, competence, student goal orientation and activity level were examined in relation to the OPTIMAL model. A total of 22 (17 M; 5 F) students and their parents provided informed consent to take part in the study and were taught four OPTIMAL lessons and four non-OPTIMAL lessons ranging across the four different games categories by their own teacher. All students completed the Task and Ego in Sport Questionnaire (TEOSQ; Duda & Whitehead, 1998), the Intrinsic Motivation Inventory (IMI; McAuley, Duncan, & Tanmien, 1987) and the Children's Perception of Optimal Challenge Instrument (CPOCI; Mandigo, 2001). Sixteen students (two each lesson) were observed by using the System for Observing Fitness Instruction Time tool (SOFTT; McKenzie, 2002). As well, they participated in a structured interview which took place after each lesson was completed. Quantitative results concluded that no overall significant difference was found in motivational outcomes when comparing OPTIMAL and non-OPTIMAL lessons. However, when the lessons were broken down into games categories, significant differences emerged. Levels of perceived competence were found to be higher in non-OPTIMAL batting/fielding lessons compared to OPTIMAL lessons, whereas levels of enjoyment and perceived competence were found to be higher in OPTIMAL invasion lessons in comparison to non-OPTIMAL invasion lessons. Qualitative results revealed significance in feehngs of skill/challenge balance, enjoyment and competence in the OPTIMAL lessons. Moreover, a significance of practically twice the active movement time percentage was found in OPTIMAL lessons in comparison to non-OPTIMAL lessons.
    • The implications of being an international medical graduate (IMG) in Canadian society : a qualitative study of foreign-trained physicians' resettlement, sense of identity and health status

      de Carvalho, Maria Auxiliadora Junqueira.; Applied Health Sciences Program (Brock University, 2007-05-21)
      This qualitative research study used grounded theory methodology to explore the settlement experiences and changes in professional identity, self esteem and health status of foreign-trained physicians (FTPs) who resettled in Canada and were not able to practice their profession. Seventeen foreign-trained physicians completed a pre-survey and rated their health status, quality of life, self esteem and stress before and after coming to Canada. They also rated changes in their experiences of violence and trauma, inclusion and belonging, and racism and discrimination. Eight FTPs from the survey sample were interviewed in semi-structured qualitative interviews to explore their experiences with the loss of their professional medical identities and attempts to regain them during resettlement. This study found that without their medical license and identity, this group of FTPs could not fully restore their professional, social, and economic status and this affected their self esteem and health status. The core theme of the loss of professional identity and attempts to regain it while being underemployed were connected with the multifaceted challenges of resettlement which created experiences of lowered selfesteem, and increased stress, anxiety and depression. They identified the re-licensing process (cost, time, energy, few residency positions, and low success rate) as the major barrier to a full and successful settlement and re-establishment of their identities. Grounded research was used to develop General Resettlement Process Model and a Physician Re-licensing Model outlining the tasks and steps for the successfiil general resettlement of all newcomers to Canada with additional process steps to be accomplished by foreign-trained physicians. Maslow's Theory of Needs was expanded to include the re-establishment of professional identity for this group to re-establish levels of safety, security, belonging, self-esteem and self-actualization. Foreign-trained physicians had established prior professional medical identities, self-esteem, recognition, social status, purpose and meaning and bring needed human capital and skills to Canada. However, without identifying and addressing the barriers to their full inclusion in Canadian society, the health of this population may deteriorate and the health system of the host country may miss out on their needed contributions.
    • Inflammatory Cytokine Concentrations in Saliva versus Plasma at Rest and in Response to Intense Exercise in Adolescent Athletes

      Beigpoor, Abrisham Jr; Applied Health Sciences Program
      Salivary and plasma concentrations of inflammatory cytokines at rest and following high-intensity interval exercise were compared in adolescent swimmers (21 male and 22 female, aged 13-17 years) to validate a non-invasive method of assessing inflammation in youth. Following provision of morning, fasted, resting blood and saliva samples, swimmers performed an intense swimming trial consisting of a maximal 200m swim, plus a high intensity interval swimming protocol (5x100m, 5x50m and 5x25m; 1:1 work-to-rest ratio), followed by post-exercise blood and saliva samples (~15 min). Salivary and plasma concentrations of interleukin-6 (IL-6), interleukin 10 (IL-10), and tumor necrosis factor alpha (TNF-α) were similar in males and females across time. Resting concentrations of IL-10 were significantly lower while IL-6 and TNF-α were significantly higher in saliva compared with plasma. IL-6 did not show a significant time effect or interaction, so although its relative decrease from pre- to post-swimming was higher in saliva than in plasma this difference was not significant (-21% vs. -3%, respectively; p = 0.06). There was a significant time-by-media interaction for IL-10, which increased from pre- to post-swimming in plasma, but this response was attenuated in saliva (51% vs. 29%; p = 0.02). TNF-α showed a significant time-by-media interaction, reflecting a decrease from pre- to post-swimming only in saliva (-27%, p = 0.01). Intraclass correlation coefficients revealed no agreement between salivary and plasma cytokine levels, and low Pearson correlations revealed no association between these measures either at rest or in response to intense swimming. In conclusion, although the overall direction of the post-exercise response was similar between saliva and plasma, the magnitude of the response was consistently different in saliva compared with plasma, which combined with the different resting concentrations and the absence of correlation between measures, suggest that salivary cytokine measures are not representative of blood levels in young athletes.
    • The Influence of Burnout Symptoms on the Relationship between Work-Life Balance and Self-Rated Health

      Novess, Jennafer; Applied Health Sciences Program
      The effects of stress at work are estimated to cost Canadian employers more than 20 billion dollars annually through absenteeism, sick leave and decreased productivity. Over the past two decades, Canadians have reported higher stress levels, increased work hours and more work performed outside of normal business hours. This work-life imbalance has far-reaching repercussions–affecting an employee’s performance as well as their health. Chronic exposure to these high levels of stress can also lead to burnout. The primary purpose of this study was to determine the magnitude in which burnout symptoms influence the relationship between work-life balance and self-rated health. The secondary purpose of this study was to determine if gender and age interactions exist in the relationship between burnout, work-life balance, and self-rated health. This cross-sectional study involved secondary analysis of 220 managers, workers and human service professionals who completed an Occupational Health Clinics for Ontario Workers’ Mental Injury Toolkit (MIT) survey for the launch of the MIT. The MIT survey is a modified form of the short version of the Copenhagen Psychosocial Questionnaire and includes expanded questioning around burnout, stress, sleep troubles, cognitive, and somatic symptoms. There were no significant differences in self-rated health based on a respondent’s gender or age, indicating that no interaction of gender and age would be required. Respondents with low self-rated health reported significantly higher burnout and work-life imbalance compared to those with high self-rated health. The regression analysis demonstrated that the magnitude in which burnout mediates the relationship between work-life balance and self-rated health was 96%. These findings support previous studies that associate high levels of work-life imbalance or burnout with poor self-rated health or health outcomes. In this study, the shared variance between work-life balance and burnout also supports recent efforts to redefine the context and causes of burnout to include non-work factors. Based on our findings, the potential exists for the development of workplace health promotion strategies that address maintaining a balance between work and home as they may improve employee health and reduce burnout.
    • The influence of cognitive resources on compensatory arm responses

      Laing, Justin Michael; Applied Health Sciences Program (Brock University, 2014-10-10)
      The purpose of this study was to determine the influence of an ongoing cognitive task on an individual’s ability to generate a compensatory arm response. Twenty young and 16 older adults recovered their balance from a support surface translation while completing a cognitive (counting) task of varying difficulty. Surface electromyographic (EMG) recordings from the shoulders and kinematics of the right arm were collected to quantify the compensatory arm response. Results indicated that the counting task, regardless of its difficulty as well as the age of the individual, had minimal influence on the onset or magnitude of arm muscle activity that occurred following a loss of balance. In contrast to previous research, this study’s findings suggest that the cortical or cognitive resources utilized by the cognitive task are not relied upon for the generation of compensatory arm responses and that older adults are not disproportionately affected by dual-tasking than young adults.
    • The influence of drug-induced dyskinesias on manual tracking in Parkinson's disease

      Lemieux, Sarah.; Applied Health Sciences Program (Brock University, 2005-06-15)
      The influence of peak-dose drug-induced dyskinesia (DID) on manual tracking (MT) was examined in 10 dyskinetic patients (OPO), and compared to 10 age/gendermatched non-dyskinetic patients (NDPD) and 10 healthy controls. Whole body movement (WBM) and MT were recorded with a 6-degrees of freedom magnetic motion tracker and forearm rotation sensors, respectively. Subjects were asked to match the length of a computer-generated line with a line controlled via wrist rotation. Results show that OPO patients had greater WBM displacement and velocity than other groups. All groups displayed increased WBM from rest to MT, but only DPD and NDPO patients demonstrated a significant increase in WBM displacement and velocity. In addition, OPO patients exhibited excessive increase in WBM suggesting overflow DID. When two distinct target pace segments were examined (FAST/SLOW), all groups had slight increases in WBM displacement and velocity from SLOW to FAST, but only OPO patients showed significantly increased WBM displacement and velocity from SLOW to FAST. Therefore, it can be suggested that overflow DID was further increased with increased task speed. OPO patients also showed significantly greater ERROR matching target velocity, but no significant difference in ERROR in displacement, indicating that significantly greater WBM displacement in the OPO group did not have a direct influence on tracking performance. Individual target and performance traces demonstrated this relatively good tracking performance with the exception of distinct deviations from the target trace that occurred suddenly, followed by quick returns to the target coherent in time with increased performance velocity. In addition, performance hand velocity was not correlated with WBM velocity in DPO patients, suggesting that increased ERROR in velocity was not a direct result of WBM velocity. In conclusion, we propose that over-excitation of motor cortical areas, reported to be present in DPO patients, resulted in overflow DID during voluntary movement. Furthermore, we propose that the increased ERROR in velocity was the result of hypermetric voluntary movements also originating from the over-excitation of motor cortical areas.
    • Influence of Estrogen on RLC Phosphorylation and Posttetanic Potentiation of Mouse Muscles with and without Skeletal Myosin Light Chain Kinase

      Fillion, Melissa; Applied Health Sciences Program
      Estrogen may influence myosin regulatory light chain (RLC) phosphorylation and posttetanic potentiation (PTP) in mouse fast twitch muscle; although the signalling pathway for this effect is unknown. The purpose of this study was to test the hypothesis that previously reported estrogen effects on RLC phosphorylation and PTP are mediated via skeletal myosin light chain kinase (skMLCK). To this end, extensor digitorum longus (EDL) muscles from female wildtype and skMLCK deficient (skMLCK-/-) mice were divided into four groups: ovariectomized (OVX) with estrogen (E+), ovariectomized without estrogen (E-), sham surgery (Sham) and intact baseline (BL). At 8 weeks of age, mice in the OVX groups were ovariectomized followed by pellet implantation at 9 weeks of age with either a 0.1 mg of 17β-Estradiol or implantation of a placebo pellet (E+ and E- respectively); sham surgeries were also performed at this time point for both genotypes. Two weeks later EDL muscles were isolated and suspended in vitro (25° C) for determination of RLC phosphorylation and PTP, except for BL groups which began contractile experiments at 9 weeks. Our results showed that RLC phosphorylation measured in muscles frozen immediately after a potentiating stimulus was not different across conditions within either genotype although values for wildtype muscles were significantly (P<0.05) greater than skMLCK-/- muscles. Consistent with these findings, the ratio of concentric twitch force (post PS / pre PS) for wildtype and skMLCK-/- muscles was similar between E+ and E+ groups although values for wildtype were greater than skMLCK-/- muscles (all data P < 0.05). However, we were unable to directly test our hypothesis as a result of unaltered estradiol levels following OVX. The inability to validate estrogen’s beneficial influence on muscle strength and contractibility in this model could be a direct result of interference with further development and growth during estrogen supplementation. Future studies should note the importance of both estrous cycles and further growth of adult mice when working with ovarian hormones. Both of these factors were likely causes of our atypical findings.
    • INFLUENCE OF INCREASED EXTRACELLULAR LEUCINE ON THE PROTEIN METABOLIC RESPONSES DURING OSMOTIC STRESS IN SKELETAL MUSCLE

      Dunbar, Brittany; Applied Health Sciences Program
      The purpose of this study was to examine the effects of increased extracellular leucine concentration on protein metabolism in skeletal muscle cells when exposed to 3 different osmotic stresses. L6 skeletal muscle cells were incubated in either a normal or supplemental leucine (1.5mM) medium set to hypo-osmotic (230 ± 10 Osm), iso-osmotic (330 ± 10 Osm) or hyper-osmotic (440 ± 10 Osm) conditions. 3H-tyrosine was used to quantify protein synthesis. Western blotting analysis was performed to determine the activation of mTOR, p70S6k, ubiquitin, actin, and μ-calpain. Hypo-osmotic stress resulted in the greatest increase in protein synthesis rate under the normal-leucine condition while iso-osmotic stress has the greatest increase under the elevated-leucine condition. Elevated-leucine condition had a decreased rate in protein degradation over the normal condition within the ubiquitin proteasome pathway (p<0.05). Leucine and hypo-osmotic stress therefore creates a favourable environment for anabolic events to occur.