Transcutaneous spinal direct current stimulation (tsDCS) is a non-invasive technique that can be used to modulate spinal function. It consists of applying a low-level direct current (DC) across the skin to modulate spinal excitability using surface electrodes. Recent research indicates that this technique can relieve musculoskeletal pain. In this study, we investigate the effect of a 20-min anodal tsDCS (2.5 mA) protocol applied over the thoracic spine on pressure pain threshold (PPT) measured in the thigh, leg and foot in healthy young adults. One primary focus of this study was to determine whether physical activity level, as a potential modulator of pain perception, could influence individual responses to tsDCS. A secondary aim was to also address the role of sex as another potential modulator of pain response. Thirty-five healthy young adults (age 18-35) were recruited for this study. Participants were assigned to either a moderately active (n=21, 12 females), or highly active group (n=14, 8 females) based on a self-report questionnaire (International Physical Activity Questionnaire). The effects were determined by comparing PPT measures at the three sites (thigh, leg, foot) at three time points with respect to tsDCS application: T0: before, T1: immediately after, and T2: 30 min post-application. Results from a multivariate analysis of variance revealed a large main effect of time (F=5.3, p<0.001) on PPTs. Univariate tests (F>16.2, p<0.001) confirmed that PPTs were significantly elevated post-application. In addition, the analysis revealed a significant “Group X Time” interaction (F=2.8, p=0.03), which was explained by a larger elevation in PPTs (thigh site) in the highly active group when compared to the moderately active group. No main effect or interaction was found for sex. Altogether, these results confirmed the anti-nociceptive effects of tsDCS application on mechanical pain threshold and further point to the importance of physical activity as a personal factor susceptible to modulate response to tsDCS.

Master of Public Health / Department of Kinesiology / Mary A. McElroy / BACKGROUND: Rural Americans face significant barriers for meeting recommended physical activity guidelines (Trivedi et al., 2015). Although studies have demonstrated adults in rural communities participate in less physical activity than their urban counterparts (Martin et al., 2005; Reis et al., 2004), the differences in physical activity for children and adolescents are not so clear. The main goal of this study was to explore potential differences among school physical activity (SPA), outside of school time physical activity (OSTPA), and sedentary behavior (SB), among rural and non-rural fourth and fifth-grade students. It was hypothesized that rural schools participate in less physical activity and more sedentary behavior than non-rural schools. Additionally, factors such as student gender and school socio-economic status were considered. METHOD: Data from the Youth Activity Profile (YAP), collected as part of the NFL PLAY60 FITNESSGRAM Partnership, is utilized to assess physical activity. The YAP captures the three constructs of SPA, OSTPA, and SB with fifteen questions (five questions each). A two-level mixed-model using SAS Proc Mixed was used to test for significant differences among groups. RESULTS: An analysis of least square means resulted in the following. Rural schools of fifth-grade students reported significantly more minutes in SPA (MD=8.68, 95% CI=-17.38, 0.01) than non-rural schools of fifth-grade students. Fourth-grade girls reported significantly fewer minutes in SPA (MD=11.1, 95% CI=9.09, 13.11), OSTPA (MD=19.55, 95% CI=17.54, 21.57), and more minutes in SB (MD=16.82, 95% CI=-22.85, -10.80) than fourth-grade boys. Fifth-grade girls reported significantly fewer minutes in SPA (MD=8.41, 95% CI=7.15, 9.67), OSTPA (MD=18.99, 95% CI=17.28, 20.70), and significantly more minutes in SB (MD=21.66, 95% CI=-26.92, -16.40) than fifth grade boys. High SES schools of fourth-grade students reported significantly fewer minutes in SB (MD=7.18, 95% CI=-14.42, 0.04) compared to low SES schools of fourth-grade students. CONCLUSION: There were no significant differences among rural and non-rural schools of fourth and fifth-grade students with respect to outside of school time physical activity and sedentary behavior. Rural schools of fifth-grade students reported more minutes in school physical activity. Gender differences were observed as girls reported significantly lower school physical activity, out of school physical activity, and significantly higher sedentary behavior than boys. Future studies need to more closely examine definitions of rural and non-rural environments, the physical activity domains under question, as well as, to examine of socioeconomic status.

Background: Adolescent girls are insufficiently active to achieve health benefits. As a result they have been targeted as a priority group for increasing physical activity levels. However, physical activity interventions for this population have had limited effect. A better understanding of the correlates of physical activity in adolescent girls may better inform intervention design. Social support describes interactions, resources, and assistance from others to influence physical activity behaviour. Social support has been linked to physical activity in adolescent girls and could be a modifiable correlate of physical activity. This thesis aimed to identify: (1) if there is a positive association between social support and physical activity in adolescent girls, and if so, (2) explore the potential pathways through which social support influences behaviour. Method: Firstly, a systematic review and meta-analysis was conducted to explore the role of different providers (e.g. parents/friends) and types of social support (e.g. emotional/instrumental) on adolescent girls’ physical activity, providing effect size estimations for different combinations of associations. Secondly, an analysis of an 8- week school based physical activity intervention for adolescent girls was conducted. This involved a mediation analysis to examine: (1) if self-efficacy mediated associations between social support and physical activity at baseline; and (2) if social support or self-efficacy mediated the effectiveness of the intervention. Finally, a qualitative study using constructivist grounded theory was conducted to investigate the mechanisms through which social support influences physical activity behaviour through conducting individual interviews with adolescent girls (n = 18). Results: The systematic review and meta-analysis identified small but significant positive associations between social support and physical activity in adolescent girls. Similar magnitudes were identified for parent and friend support effect sizes. The mediation analysis found that self-efficacy mediated the relationship between social support and physical activity, however, social support did not mediate the effectiveness of a physical activity intervention for adolescent girls. The results of the grounded theory study suggest that social support can influence adolescent girls’ physical activity through enjoyment, self-efficacy, overcoming barriers to physical activity, motivation, and performance improvements, as well as enabling physical activity. Conclusions: Whilst only small significant associations between social support and physical activity in adolescent girls were identified, social support may also indirectly influence physical activity through enjoyment, self-efficacy, overcoming barriers, motivation, performance improvements and enabling physical activity. There may be promise in targeting these constructs through social support behaviour change strategies in physical activity interventions for adolescent girls.

Pregnancy is an unique period in a woman’s life in which her body undergoes rapid and drastic changes. Historically, physical activity was thought to be dangerous during pregnancy and women were recommended to avoid engaging in most physical activities. Mechanical efficiency, the ratio of external work and energy required to perform a task, is an important consideration when addressing the safety of physical activity, but also when defining recommendations to this population. Currently, there is limited literature that characterizes the change in mechanical efficiency across pregnancy. Of the available literature, suboptimal methodologies were employed, resulting in conclusions that conflict with what would be expected. The purpose of this thesis was to characterize mechanical efficiency across gestation and to compare with non-pregnant women. Women performed a standardized treadmill task in early, mid, and late pregnancy, and energy dynamics were measured. Results showed that energy requirements and external work performed increased over time, and that these were in relation to gestational weight gain. Pregnant women did not exhibit a change in the efficiency of performing a walking task. Overall, these results add to the current literature that supports women’s engagement in physical activity during pregnancy.

Magister Artium (Sport, Recreation and Exercise Science) - MA(SRES) / Physical inactivity is increasing among adolescents worldwide and may be contributing to the increasing prevalence of overweight and obesity. South African adolescents are physically inactive and obesity has become an alarming trend. Physical activity behaviours have multiple levels of influence that include predisposing factors, reinforcing factors and enabling factors. This study aimed to identify the predisposing, reinforcing, and enabling factors of physical activity and which ones were the strongest predictors of physical activity participation among adolescents in the Western Cape. The study sample was conveniently selected from two schools in the Metropole South Education District. Using the children’s physical activity questionnaire and the children’s physical activity correlates questionnaire, a sample of 348 participants completed the questionnaires. Demographic variables were analysed using descriptive statistics which included means and standard deviations. Pearson correlation and regression analysis were performed to determine the relationship between the variables and to determine the strongest predictors of physical activity overall. Parental influence (r=0.236, p<0.01), peer influence (r = 0.012, p<0.05), perceived physical activity self-efficacy (r=0.212, p<0.05) and perceived physical activity competence (r = 0.192, p < 0.05) were all strong predictors of PA. However, parental influence was the strongest predictor overall (r=0.236, p<0.01). Adolescents are more likely to participate in physical activity if their parents encourage, support and participate in physical activity with them.

Background: While the physical and mental health benefits of regular participation in physical activity (PA) are well-known, accelerometer data indicates up to 68% of adult Canadians are not meeting PA guidelines. Thus promoting PA is a priority. Clearly, regular exercise is an important means to acquire PA for many of the population. Much of the exercise promotion research in this area is conducted under the guide of a social cognitive framework, and does not take into consideration reflexive, sub-conscious processes of behaviour change such as identity. Exercise identity has been linked to increased frequency, duration, and intensity of PA participation. However, there is limited work exploring the antecedents of developing an exercise identity, or ways in which an intervention could target antecedent themes in order to aid in the development of an exercise identity. Objective: The purpose of this research was two-fold. Firstly, in Study 1, I explored the lived PA experience and how experiences in youth relate to exercise identity in adulthood. Secondly, in Study 2, I explored the feasibility of an identity-based intervention, using theory and emergent themes from Study 1 to guide my intervention targets. iv Methods: In Study 1 and Study 2, I recruited male and female participants from the undergraduate population at the University of Victoria. I used mixed methods throughout. Study 1 – I conducted semi-structured interviews to collect data on participants’ PA experiences, using a pragmatic qualitative framework to guide my research process. I was interested in both past and present experiences which may have contributed to the development of participants’ current exercise identities. I used thematic analysis and open coding to determine core themes. Study 2 – I conducted a six week, randomized feasibility trial in order to explore the feasibility of an intervention designed to increase a person’s exercise identity. Participants were randomly assigned to a standard social cognitive intervention group (education materials, goal-setting skills) or an augmented identity formation group (receiving the same information as the standard group in addition to educational and applied strategies for increasing identity). At the conclusion of the study, I conducted exit interviews with members of both groups to get more detailed information about the acceptability and enjoyment of the interventions. Results: Study 1 – I recruited 10 participants with varying exercise identity strengths (4 high, 3 medium, 3 low). Five themes emerged as related to the development of an exercise identity, including skill, enjoyment, variety, extracurricular activity participation, and sport ownership. Passion also emerged as a theme in high and medium identifiers, but not low identifiers. Study 2 – I recruited 20 participants and randomized them to either the standard or augmented intervention group with a 1:1 ratio. The recruitment rate was 26%, retention was 90%, and the mean satisfaction score for the standard intervention group was 2.69 (SD = 0.62), and the augmented intervention group was 2.83 (SD = 0.40). Both the augmented intervention and v standard intervention groups increased their PA levels (η2 = 0.25), and exercise identity levels (η2 = 0.43), however interaction effect sizes were small (η2 ~ 0.02), indicating no greater change in the augmented intervention group compared to standard intervention group. Discussion: Study 1 – The emergent themes both reflect existing literature (social cognitive models, self-definition model, and multi-process action control) in terms of relationship to PA and antecedents to identity development. Recommended future intervention targets include emphasizing enjoyment, focusing on feelings of skill/competence, and increased exposure to a variety of PAs. Additionally, passion as an indicator for an exercise identity may be a goal of future identity-based research. Study 2 – Both control and intervention group participants ranked the study highly in terms of feasibility and acceptability. Intervention group participants felt more connected to the researcher and engaged more with materials, indicating satisfaction with the content covered over and above that of the control group. Both intervention and control groups saw increases in PA levels and exercise identity scores, however the effect sizes for between group differences were low. Based on strong feasibility ratings, a full-scale randomized controlled trial is recommended. / Graduate

Objective data from national surveillance programmes show that, on average, individuals accumulate high amounts of sedentary time per day and only a small minority of adults achieve physical activity guidelines. One potential explanation for the failure of interventions to increase population levels of physical activity or decrease sedentary time is that research to date has been unable to identify the specific behavioural levers in specific contexts needed to change behaviour. Novel technology is emerging with the potential to elucidate these specific behavioural contexts and thus identify these specific behavioural levers. Therefore the aims of this four study thesis were to identify novel technologies capable of measuring the behavioural context, to evaluate and validate the most promising technology and to then pilot this technology to assess the behavioural context of older adults, shown by surveillance programmes to be the least physically active and most sedentary age group. Study one Purpose: To identify, via a systematic review, technologies which have been used or could be used to measure the location of physical activity or sedentary behaviour. Methods: Four electronic databases were searched using key terms built around behaviour, technology and location. To be eligible for inclusion papers were required to be published in English and describe a wearable or portable technology or device capable of measuring location. Searches were performed from the inception of the database up to 04/02/2015. Searches were also performed using three internet search engines. Specialised software was used to download search results and thus mitigate the potential pitfalls of changing search algorithms. Results: 188 research papers met the inclusion criteria. Global positioning systems were the most widely used location technology in the published research, followed by wearable cameras and Radio-frequency identification. Internet search engines identified 81 global positioning systems, 35 real-time locating systems and 21 wearable cameras. Conclusion: The addition of location information to existing measures of physical activity and sedentary behaviour will provide important behavioural information. Study Two Purpose: This study investigated the Actigraph proximity feature across three experiments. The aim of Experiment One was to assess the basic characteristics of the Actigraph RSSI signal across a range of straight line distances. Experiment Two aimed to assess the level of receiver device signal detection in a single room under unobstructed conditions, when various obstructions are introduced and the impacts these obstructions have on the intra and inter unit variability of the RSSI signal. Finally, Experiment Three aimed to assess signal contamination across multiple rooms (i.e. one beacon being detected in multiple rooms). Methods: Across all experiments, the receiver(s) collected data at 10 second epochs, the highest resolution possible. In Experiment One two devices, one receiver and one beacon, were placed opposite each other at 10cm increments for one minute at each distance. The RSSI-distance relationship was then visually assessed for linearity. In Experiment Two, a test room was demarcated into 0.5 x 0.5 m grids with receivers simultaneously placed in each demarcated grid. This process was then repeated under wood, metal and human obstruction conditions. Descriptive tallies were used to assess the signal detection achieved for each receiver from each beacon in each grid. Mean RSSI signal was calculated for each condition alongside intra and inter-unit standard deviation, coefficient of variation and standard error of the measurement. In Experiment Three, a test apartment was used with three beacons placed across two rooms. The researcher then completed simulated conditions for 10 minutes each across the two rooms. The percentage of epochs where a signal was detected from each of the three beacons across each test condition was then calculated. Results: In Experiment One, the relationship between RSSI and distance was found to be non-linear. In Experiment Two, high signal detection was achieved in all conditions; however, there was a large degree of intra and inter-unit variability in RSSI. In Experiment Three, there was a large degree of multi-room signal contamination. Conclusion: The Actigraph proximity feature can provide a binary indicator of room level location. Study Three Purpose: To use novel technology in three small feasibility trials to ascertain where the greatest utility can be demonstrated. Methods: Feasibility Trial One assessed the concurrent validity of electrical energy monitoring and wearable cameras as measures of television viewing. Feasibility Trial Two utilised indoor location monitoring to assess where older adult care home residents accumulate their sedentary time. Lastly, Feasibility Trial Three investigated the use of proximity sensors to quantify exposure to a height adjustable desk Results: Feasibility Trial One found that on average the television is switched on for 202 minutes per day but is visible in just 90 minutes of wearable camera images with a further 52 minutes where the participant is in their living room but the television is not visible in the image. Feasibility Trial Two found that residents were highly sedentary (sitting for an average of 720 minutes per day) and spent the majority of their time in their own rooms with more time spent in communal areas in the morning than in the afternoon. Feasibility Trial Three found a discrepancy between self-reported work hours and objectively measured office dwell time. Conclusion: The feasibility trials outlined in this study show the utility of objectively measuring context to provide more detailed and refined data. Study Four Purpose: To objectively measure the context of sedentary behaviour in the most sedentary age group, older adults. Methods: 26 residents and 13 staff were recruited from two care homes. Each participant wore an Actigraph GT9X on their non-dominant wrist and a LumoBack posture sensor on their lower back for one week. The Actigraph recorded proximity every 10 seconds and acceleration at 100 Hz. LumoBack data were provided as summaries per 5 minutes. Beacon Actigraphs were placed around each care home in the resident s rooms, communal areas and corridors. Proximity and posture data were combined in 5 minute epochs with descriptive analysis of average time spent sitting in each area produced. Acceleration data were summarised into 10 second epochs and combined with proximity data to show the average count per epoch in each area of the care home. Mann-Whitney tests were performed to test for differences between care homes. Results: No significant differences were found between Care Home One and Care Home Two in the amount of time spent sitting in communal areas of the care home (301 minutes per day and 39 minutes per day respectively, U=23, p=0.057) or in the amount of time residents spent sitting in their own room (215 minutes per day and 337 minutes per day in Care Home One and Two respectively, U=32, p=0.238). In both care homes, accelerometer measured average movement increases with the number of residents in the communal area. Conclusion: The Actigraph proximity system was able to quantify the context of sedentary behaviour in older adults. This enabled the identification of levers for behaviour change which can be used to reduce sedentary time in this group. Overall conclusion: There are a large number of technologies available with the potential to measure the context of physical activity or sedentary time. The Actigraph proximity feature is one such technology. This technology is able to provide a binary measure of proximity via the detection or non-detection of Bluetooth signal: however, the variability of the signal prohibits distance estimation. / The Actigraph proximity feature, in combination with a posture sensor, is able to elucidate the context of physical activity and sedentary time.

Made available in DSpace on 2015-07-22T20:49:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-09-29. Added 1 bitstream(s) on 2015-08-11T03:26:29Z : No. of bitstreams: 1 Publico-370.pdf: 460541 bytes, checksum: 0bd09fcbf1ed06758089d085f2c56d6e (MD5) / Introdução: O Transtorno de déficit de atenção e hiperatividade (TDAH) é o transtorno infantil mais prevalente do mundo e se relaciona com deficiências de catecolaminas em testes físicos, bioquímicos e cognitivos; por outro lado alguns exercícios são conhecidos como potentes estimuladores de catecolaminas, tanto central quanto e perifericamente. Objetivo: Testar a hipótese das catecolaminas (CA) centrais como as responsáveis pelo aumento na velocidade de reação vistas após atividades físicas e medir o impacto que esforços físicos agudos supra limiares apresentam na atenção sustentada de 25 crianças diagnosticadas com TDAH, conforme os critérios do DSM-IV. É possível que a prática desportiva possa ser positiva no manejo dos sintomas de TDAH. Método: As crianças foram divididas entre usuárias (US) e não usuárias (NUS) de Metilfenidato (MTP), os grupos foram comparados quanto a aspectos antropométricos, cognitivos e fisiológicos assim como os efeitos crônicos da droga, sobre a cognição, imediatamente após atividades físicas intensas. Resultado: A performance cognitiva após esforços físicos não foi, de maneira relevante, modificada pelo MTP. Observamos melhoras significativas no tempo de resposta, assim como normalização da impulsividade e das medidas de vigilância por meio do CPT teste. Conclusão: Estes resultados sugerem que a melhora cognitiva usualmente vista após a prática desportiva não são CA dependentes; adicionalmente exercícios físicos podem ser de auxílio no alívio dos sintomas de TDAH. / Attention deficit hyperactivity disorder (ADHD) is related to a deficiency of central catecholamines (CA) in cognitive, biochemical, and physical tests, and pharmaceutical intervention may have no effect if it is not accompanied by changes in the environment. The objective of our study was to test the hypothesis that central CA are responsible for the increase in speed reaction seen after physical activity (PA) and to measure the impact of high intensity PA on the sustained attention of 25 children diagnosed with ADHD consistent with the Disease Statistical Mental-IV (DSM-IV) criteria. It is possible that practicing sports assists in the management of the disorder. The children were divided between users (US) and non-users (NUS) of methylphenidate (MTP), and the groups were compared to evaluate the effect of the drug on cognition after PA. Post-exercise performance on Conner’s Continuous Performance Test-II (CPT) was not affected by MTP, we observed significant improvements in response time, and we saw normalization in the impulsivity and vigilance measures. These results suggest that the improvements in cognition after physical effort are not CA dependent. Additionally, our results suggest that children’s attention deficits can be minimized through PA irrespective of treatment with MTP. Additional studies are necessary to confirm that exercise mitigates the harmful symptoms of ADHD. / TEDE

Ageing is associated with a decline in health. Physical activity is known to attenuate this decline; however a large amount of the general population does not participate in the recommended amount of physical activity. Time is reported in middle-aged and elderly populations as a major barrier to exercise participation. Therefore time-efficient and effective exercise paradigms are required to encourage engagement in physical activity, improve health and reduce the risk of disease. The aim of this thesis was to investigate the potential of using high intensity training (HIT) as an exercise paradigm to promote optimal ageing. Seventy seven participants (age range 35-75 years) were recruited to take part in HIT protocols consisting of 10 x 6 second sprints interspersed with a minimum of 1 minute recovery. Prior to taking part in the training participants underwent a series of baseline measures which included physical function tests, predicted aerobic capacity, oral glucose tolerance test, fasting lipid profile, body composition and blood pressure. After 6-10 week of training, participants were retested to determine the effectiveness of HIT. Following 6, 8 or 10 weeks of HIT, physical function was significantly improved by 9-29% in both middle aged and elderly populations. Aerobic capacity was increased by 10.5% in middle aged participants and by 5.1-8.7% in elderly participants. Blood glucose clearance, as assessed by area under the curve, was decreased by 6% in the middle aged participants and 4.2-17% in the elderly population. Systolic blood pressure was unchanged in the middle aged participants but was reduced by 5.4-8% in the elderly participants. Following 10 weeks of HIT, circulating lipid profile was significantly improved in the elderly by 11-25.9%. These improvements are speculated to be a result of HIT-induced adaptations in skeletal muscle mitochondrial, cardiac, vascular and metabolic function. Very short duration sprints provide rapid improvements in various aspects of health and could be utilised to promote optimal ageing.

Master of Public Health / Kinesiology / David A. Dzewaltowski / Background: This study examined youth moderate-to-vigorous physical activity (MVPA) levels during flag football practice and compared youth MVPA in practices led by trained or untrained, and by experienced or inexperienced coaches. Methods: Boys (n = 111, mean age= 7.9 ± 1.2 years) from 14 recreation flag football teams wore an accelerometer during two practices. Each team's volunteer head coach reported prior training and coaching experience. Results: Mixed-model team-adjusted means showed the proportion of practice time spent in sedentary (13 ± 1%), MVPA (34 ± 2%), and vigorous (12 ± 1%) activity. Practice contributed ~20 minutes of MVPA towards public health guidelines. There was no significant difference in percentage time spent in MVPA between teams with trained (mean = 33.3%, 95% CI = 29.4%, 37.2%) and untrained coaches (mean= 35.9%, 95% CI = 25.5%, 42.4%) or between experienced (mean = 34.1%, 95% CI= 30.2%, 38.0%) and inexperienced coaches (mean = 33.8, 95% CI = 27.9%, 39.7%). Conclusion: Although sport provides a setting for youth to be physically active at a moderate to vigorous level, two-thirds of practice was spent sedentary or in light activity. Having participated in a coach training program was not associated with higher MVPA. Further research is needed to inform volunteer coach training programs that provide coaches with skills necessary to increase the percentage of practice time spent in MVPA.