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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

The effects of continuous, intermittent and mode of exercise on mechanical bone remodelling

Montgomery, Gallin John Hodgshon January 2017 (has links)
Bone health is known to deteriorate with age, which can increase the risk of osteoporotic fractures and subsequently all-cause mortality. Current life expectancies are higher than ever before and with our ageing population, osteoporosis and low bone density levels are an ever growing problem that command a lot of medical attention and resources. Women are at a greater risk than men due to increased rates of bone loss that occur in the early years following the menopause. Mechanical loading in the form of exercise is known to reduce the rates of postmenopausal bone loss although an optimal exercise programme is yet to be established. Furthermore, investigations conducted with animals have found intermittent mechanical loading to provide a greater stimulus for bone adaptation than continuous mechanical loading, this has not been investigated in human populations to date. The aim of this thesis was to establish a sufficient exercise mode for stimulating bone adaptation in postmenopausal women and investigate the effects of continuous and intermittent exercise on postmenopausal bone loss. This was attempted with a 12 month randomised controlled trial with postmenopausal women. The first study gave a systematic review of the current literature that investigated continuous or intermittent exercise. The review found that as the studies were not designed to specifically analyse continuous or intermittent exercise, there were numerous problems regarding the control of previous exercise programmes with regards to defined exercise and rest intervals. This was due to the design of the included studies, as many of them were not specifically designed to analyse the different effects of continuous and intermittent exercise on bone mineral density (BMD). In addition, BMD outcomes were not reported in a standardized manner, which complicated the comparisons drawn. From this investigation, it was evident that well-controlled exercise interventions (using a single exercise), are required for the comparison of the effect of continuous and intermittent exercise on BMD in human populations. The second study investigated the feasibility of developing a non-motorised treadmill exercise intervention that included both continuous and intermittent exercise groups. Non-motorised treadmill (NMT) locomotion allows for the instantaneous quantification of ground reaction forces (GRF) and is well suited to both continuous exercise and intermittent exercise with the potential for the use of a range of intermittent running based protocols. In order to establish the osteogenic potential of this mode of exercise, it was necessary to quantify the mechanical loading parameters. This study found that loading parameters showed large reductions during NMT locomotion when compared to overground or motorised treadmill locomotion (24 to 29 %), which could potentially compromise the level of bone adaptation if this mode of exercise was used for intervention purposes. The third study investigated the loading parameters of more traditional high impact exercises in a population of postmenopausal women. All exercises were performed under both continuous and intermittent conditions to assess for consistency during the two conditions. This project showed that countermovement jumps (CMJ) and box drops (BD) produced the highest loading parameters when compared to heel drops (HD) and stamping (STP) (d = 0.83 – 2.38), along with no statistical differences between continuous and intermittent conditions (continuous: 10.7 ± 4.8 g for CMJ, 9.6 ± 4.1 g for BD; intermittent 10.0 ± 5.0 g for CMJ, 9.5 ± 4.0 g for BD). CMJ, BD and HD exercises all appeared to generate a sufficient level of peak acceleration and acceleration gradient for osteogenic adaptation however. For consistency purposes and the fact that no equipment was required, CMJs were selected as the most appropriate home-based exercise for use in a 12 month intervention to reduce postmenopausal bone loss. The fourth study investigated the effects of continuous and intermittent exercise on BMD in early postmenopausal women over the course of a 12 month randomised control trial. Unfortunately the study was underpowered and in addition, the findings showed no statistically significant differences in the bone response between groups. Only the control group experienced a statistically significant loss in both lumbar spine (-2.7% [95%CI: -3.9 to -1.4]) and femoral neck (-3.0% [95%CI: -5.1 to -0.8]) BMD, which exceeded the 95% least significant change at the lumbar spine and femoral neck in 57% of control group participants. There appeared to be no beneficial effect of continuous or intermittent exercise on BMD, hip structural analysis (HSA) parameters or muscular force characteristics when compared to a control group however. In conclusion, this thesis has identified that future research should further investigate the effects of continuous and intermittent exercise on BMD with appropriately controlled randomised control trials, with greater participant numbers. Whilst CMJ and BD provide adequate loading parameters, this does not translate into BMD adaptations. Continuous and intermittent CMJ exercises had no effect on reducing postmenopausal BMD loss at the lumbar spine and the femoral neck, although further investigation is required in an adequately powered study.

The effect of neuromuscular training on fatigue resistance in female footballers

Reed, Georgina January 2017 (has links)
ACL injury is predominant in female footballers largely due to a combination of kinetic and neuromuscular risk factors. The majority of ACL injuries in football occur during an unanticipated cutting manoeuvre, and the risk of this injury is heightened during the final 30 minutes of each half of match-play. Due to an increased injury incidence towards the end of match-play, it is possible that fatigue might serve as a risk factor for ACL injury. However, there currently exists limited research examining the effects of fatigue on a variety of kinetic and electromyographic variables in female footballers during an unanticipated cutting manoeuvre. Neuromuscular training programmes have been utilised in injury prevention studies and proven effective in reducing injury incidence by improving certain kinetic and neuromuscular ACL injury risk factors. The overall aim of this thesis is to examine the effectiveness of neuromuscular training on the fatigue resistance of ACL injury risk factors in female footballers. Study one of this thesis examined the reliability of a combination of kinetic and electromyographic measures in female footballers performing an unanticipated cutting manoeuvre. There were no significant differences in mean values and large to nearly perfect correlations (ICC = 0.49 - 0.96) for all kinetic variables. The majority of kinetic variables displayed a CV of less than 10%, with the exception of loading rates and time to peak force (CV% = 17.33 - 24.51). In comparison to previous research, electromyographic variables displayed a greater range of typical error (CV% = 17.6 - 129.2); however, the majority of electromyographic variables displayed a large, very large or nearly perfect correlation (ICC = 0.26 – 0.91) and no significant differences in the mean score. In line with previous research, standards of reliability, and anticipated changes in response to acute fatigue, all kinetic and electromyographic variables were deemed acceptable to use in subsequent studies. Kinetic variables showed better reliability than electromyographic variables, which was to be expected due to electromyographic measures being a physiological measure. Previous research has established that 16 - 18 year old female footballers are at highest risk of ACL injury, and it is most commonly caused during performance of an unanticipated cutting manoeuvre. It has also been established that the majority of injuries in female football are sustained in the last 30 minutes of each half when fatigue is present. Therefore, acute fatigue appears to be an influential risk factor for ACL injury. Study two of this thesis examined the effects of acute fatigue on the electromyographic and kinetic ACL injury risk factors in 16 - 18 year old female footballers, when performing an unanticipated cutting manoeuvre. A modified SAFT90 protocol was used to mimic football match-play. Data showed that during the unanticipated cutting manoeuvre following the SAFT90, participants produced greater GRF (vGRF; possibly, apGRF very likely), lower GCT (very likely), increased background hamstring activation (0 - 30 ms; very likely) and increased short-latency feedback activation of the hamstrings (31 - 60 ms; likely and possibly). Results suggested that following a simulated match-play protocol, female footballers experienced greater force absorption while utilising a safer muscle recruitment strategy. Therefore, injury prevention training should seek to improve a player’s aility to tolerate ground reaction forces when experiencing acute fatigue, with a large emphasis on enhancing neuromuscular control within the hamstrings muscle group.

Sport and physical activity participation and sedentary behaviour among adolescents : exploring the transition from compulsory education

Owens, Christopher Stephen January 2012 (has links)
The move out of compulsory education is a key transition period in adolescents' lives. The aim of the present study was to investigate physical activity and sedentary behaviour (using 'screen time' as the proxy measure) among adolescents during the transition from completing compulsory education to entering further education, training or (un)employment. A prospective population-based longitudinal design was adopted, using a large cohort of adolescents in Gloucestershire. A questionnaire was administered to participants at two time points (baseline and follow-up). At baseline, 2204 Year 11 pupils (aged 14 to 17 years) and at follow-up, 886 participants from the baseline sample (aged 15 to 17 years) completed the questionnaire. ( For all statistical analyses performed, two sets of analysis were conducted. Analysis one included the final sample of participants (n = 663) who had an associated output area (OA) code to include in statistical analyses and analysis two included the final sample of participants (n = 834) who did not have an associated OA code included in statistical analyses. Since the overall findings for each analysis were similar, only findings from analysis one are presented. For physical activity, there was a significant change in the number of participants meeting guidelines at baseline but not meeting guidelines at follow-up. For screen time status, there was no significant change between baseline and follow-up. Binary logistic regression (BLR) revealed that for gender, in comparison to males, females were 52.4% less likely to meet guidelines for physical activity at follow-up. Meanwhile, BLR revealed that there were no significant associations with screen time status at follow-up. Further BLR for the decline in physical activity through the transition, revealed that for gender, in comparison to males, females were 42.4% less likely to move from meeting guidelines at baseline to not meeting guidelines at follow-up (i.e., physical activity decline was associated with being male). The findings of the present study have demonstrated: i) a decline in physical activity through the transition; ii) the high proportion of adolescents not meeting guidelines for screen time at either baseline or follow-up; and iii) associations between gender and physical activity during this transitional period. There is a need for future research to longitudinally examine adolescents' physical activity and sedentary behaviour during this transitional period.

Intended actions, unintended consequences : towards a processual understanding of exercise referral schemes

Henderson, Hannah Erica January 2017 (has links)
Whilst the benefits of physical activity have been well documented, many in the UK population remain insufficiently active to substantively benefit their health, placing individuals at greater risk of developing a range of non-communicable diseases and conditions. As a large percentage of the population accesses primary care, at least on an annual basis, the use of this health care sector to advocate increased physical activity has become widespread. Exercise referral schemes (ERSs) have enabled primary care professionals to refer their patients, typically to a local leisure facility, for supervised exercise. ERSs have seen prolific growth across the UK since their conception in the 1990s and yet their effectiveness has remained in question. Despite a variety of research designs being employed, evidence regarding schemes’ effectiveness continues to be inconclusive. Within the existing research literature, the complexity of context within which ERSs operate has remained largely overlooked; specifically, how individual interpretations of ERSs might be co-produced according to the interactions between those central to the service, and how this might influence both service delivery and impact. This study, therefore, aimed to address these lacunae by exploring participants’ understanding of ERSs, and how these perceptions contoured ERS service provision. The research focused on one case-study ERS in the East of England. Semi-structured interviews were employed through a combination of group and one-to-one interviews, with 27 participants (15 patients, 7 exercise practitioners, 5 health professionals) who were central to the ERS at a delivery level, and a further 5 (1 ii district manager, 2 representatives from the County Sports Partnership and 2 representatives from Public Health) one-to-one interviews were conducted with individuals who represented the strategic management of ERSs. A process sociological lens was adopted to provide novel insights into participants’ perceptions of ERSs, their role and their ability to influence ERS service provision. Data were also supported by self-elicited reflections born from the researcher’s ‘insider’ position to the County’s ERS. Thematic analysis generated salient themes that showed conflicting interpretations of ERS service provision, and perceptions of scheme receipt and impact. Data highlighted that the networks of relationships in which individuals were situated not only contoured participant experiences but shaped the delivery processes of ERSs. Individual ‘I’ identities were situated within interdependent networks of ‘we’ and ‘they’ relationships, where identifiable groups were formed according to individuals’ perceived role within the scheme. Relationships between individuals and groups were in a tensile state, marked by power balances that had impacted on service provision but also the associated meaning of ERSs, producing interesting, yet unexpected and unintended outcomes. Such findings could prove useful to policy-makers, those responsible for commissioning ERSs, and practitioners, as well as those in similar roles for other multi-agency interventions. By facilitating enhanced understanding of the complexities of this physical activity intervention, findings suggest how the actions and interpretations of those central to a service can fundamentally alter delivery mechanisms and receipt, potentially influencing the very existence of the intervention, or in this case ERSs.

Importance of rhythm for the optimum performance of motor skills

MacPherson, Alan Cameron January 2009 (has links)
The overall aim of the thesis was to appraise critically the role that rhythm can play as an effective focus for high level athletic performance. This aim was realised through a series of staged objectives. In a desktop study, the potential importance of rhythm was investigated across the performance spectrum (chapter 2). Having established the scope and potential utility of the construct, it was necessary to determine whether it was possible to isolate rhythm, to establish whether it was associated with skilled execution, and whether it was a genuine, naturally occurring, phenomenon (chapter 3). Having established significant differences in recalled movement patterns between skilled and non-skilled participants, the third objective was to determine the impact of differing mental sets on elite competitors in a performance environment (chapter 4). Interestingly, low levels of movement variability in horizontal jumps were positively associated with jumps of greater distance in the majority of athletes studied. This finding has implications for the way performers should be instructed, how high performance interventions are designed, and it questions the pre-eminent perceptual paradigm in this area of human performance. Finally, the thesis aimed to determine if rhythm can be applied and manipulated as a performance aid. To this end, two case studies are presented (chapters 5 & 6) which outline the varied means through which rhythm can be manipulated according to the performance needs of the athlete, both in terms of reducing movement variability, and improving overall performance.

The development, validation and implementation of the multidimensional motivational climate observation system in sport

Smith, Nathan John January 2015 (has links)
Grounded in an integrated framework (Duda, 2013) that pulls from achievement goal theory (AGT; Nicholls, 1989) and self-determination theory (SDT; Deci & Ryan, 2000) framework, the current thesis presents the steps taken to develop and test the Multidimensional Motivational Climate Observation System (MMCOS) in sport. Almost exclusively, research examining the motivational coaching environment from an AGT and/or SDT perspective has relied on athletes’ self-reports of the environment. Few studies have used an observational methodology to rate objective features of the coaching environment as emphasized within AGT and SDT-based research, and no studies have integrated AGT and SDT to provide an objective assessment of the motivational environment. To address these limitations, the thesis begins by outlining the development and validation of the MMCOS in Chapter 2. In Chapter 3, the MMCOS is used to examine the relationship between observed and perceived dimensions of the coaching environment and subsequent relations with athlete motivation. Following this, the objectively rated motivational environment is examined in training and match contexts (Chapter 4). Finally, the MMCOS is employed to further understand the dynamics of the observed and perceived motivational coaching environment in an elite sport setting (Chapter 5). Findings from the present set of studies provide initial evidence for the reliability and validity of the MMCOS when utilized within different samples (i.e., grassroots and elite) and contexts. In the future, the MMCOS could be used alongside self-report measures and provide an alternative assessment of the coach-created motivational environment in sport, as well as contribute to the evaluation of coach-education programmes grounded in an AGT and SDT perspective.

Influence of nutritional interventions to optimise fat metabolism and exercise performance

Hodgson, Adrian January 2013 (has links)
This thesis investigated three commonly used nutritional interventions that are often claimed to alter substrate metabolism and improve exercise performance: green tea extract (GTE), coffee and vitamin D. GTE and caffeine have been hypothesized to increase fat oxidation at rest and during exercise, thereby lowering the reliance on skeletal muscle glycogen and improving endurance exercise capacity. We observed that 7 days GTE supplementation resulted in an increase in metabolites related to fat and energy metabolism at rest but not during moderate intensity exercise. The current thesis also found that endurance exercise performance can be improved to the same extent by either using coffee or caffeine. However, these improvements in endurance exercise performance were independent of changes to fat oxidation during exercise. We also demonstrate that athletes living in Birmingham, United Kingdom, display a high prevalence of vitamin D deficiency during the winter and thus require nutritional support. However, despite the high prevalence of vitamin D deficiency, there was no association between vitamin D status and skeletal muscle function or exercise performance. Short term vitamin D supplementation at doses above the current recommended daily allowance was highly effective in correcting vitamin D deficiency to sufficiency. But supplementation did not alter any measure of performance.

Managing tourism in national parks : case studies of Taman Negara and Kinabalu Park, Malaysia

Khalifah, Zainab January 1997 (has links)
This study aims to examine the concept of national parks as tourists destination. It will explore the relationship between tourism and conservation; discuss specific issues of tourism planning in national parks; and propose a conceptual framework of tourism management in national parks which will examine how visitor recreational opportunities are influenced by three main factors: visitor management, service management and resource management. Taman Negara, the largest national park in Malaysia, located in the central part of Peninsular Malaysia and Kinabalu Park, situated in the northern part of the island of Borneo are utilised as case studies. These two national parks are among the oldest national parks in Malaysia, having established themselves as important tourist destinations. They are considered by the Malaysia Tourism Promotion Board (MTPB) as promising tourism destinations associated with 'nature-based' or 'ecotourism' and are being promoted as important 'add-on' destinatio ns in an effort to increase tourists length of stay and to stimulate regional development. The primary data in this study has two main purposes. The first is to examine the socio-demographic profile of local and foreign visitors to the parks; determine the differences in their trip characteristics; their perception of the park's services and facilities; and their evaluation on the charges of facilities and user fees. The second is to examine the socio-demographic characteristics of local communities living in the vicinity of the parks and explore the economic, environmental and socio-cultural impacts of tourism as perceived by the local communities. Findings of the study highlights the different characteristics of local and foreign visitors to the parks, such as their perception on the information and interpretative services; user fees in the parks; and the favourable perception of local communities towards the development of tourism. Foreign visitors perceived the information and interpretative services provided local visitors, while the latter perceived the user fees in the park to be higher compared to former. Strategy implication for the parks include the introduction a two-tier entrance fee, park personnel who are knowledgeable in various fields, besides natural sciences and a more active involvement of the park management with the related tourism agencies and local communities.

The development of tourism in Kenya and The Gambia : a compartive analysis

Dieke, Peter U. C. January 1988 (has links)
The purpose of this study is to examine tourism development planning in Kenya and The Gambia; to compare and contrast their relative approaches to tourism development, and to assess their implications; to use the syntheses to identify hypotheses which might be used to stimulate tourism in developing countries. Concepts from tourism management (planning) and political economy (development) provide the theoretical framework for the investigation. Three hypotheses are put forward: Unless the tourism sector is managed well, problems are unavoidable. Second, because of weight of collective experience, management cannot obviate the problems but can help to solve them. Third, although planning for the sector may be good, this is only the input. Questions may be asked about structure, or about implementation. To test the hypotheses, Africa and the United Kingdom are chosen as field-work areas. The target is at two levels - demand and supply. The demand focuses on U.K. tour operators 'selling' East and West African tourist destinations. A short questionnaire, consisting of various factors considered important in choosing destinations, is constructed. The questionnaire seeks to ascertain tour operators' opinions on the competitiveness of Kenya and The Gambia as tourist destinations, relative to other African rivals. The results of the survey are incorporated into actual field-work in Africa. The supply side concentrates on a range of the travel trade operating in Kenya and The Gambia. It includes airlines, hoteliers, government officials. The purpose is to obtain sellers' view - the image the countries want to present overseas. The interview technique is used to generate field-work data. In both cases, the emphasis is to find out the problems of development as seen by the countries themselves and also the problems and difficulties experienced by tour operators in 'selling' the destinations. The thesis concludes on three notes: that the success of tourism in developing countries will depend largely on the need for planning, the need for flexibility, and the need for caution. It is argued that to disregard these propositions could spell a disaster for the tourism industry. The implication for developing countries is that if tourism is to provide the springboard for a realisation of the 'basic needs' cry of their citizens, in terms of an improvement of opportunity and quality of life, then the tourism sector needs to be planned. There have to be slack and selective tendencies built into it. These three factors are the main ingredients of success.

A logistic regression model of the decision of volunteers to enter a sports coach education programme

Wilson, Brian January 2002 (has links)
200,000 voluntary coaches ensure that the large investments in sports facilities in the UK are effectively used and that the athletes experience a healthy life. In a socioeconomic period in which volunteering may be diminishing, more coaches to successfully implement the national strategy for sport. Yet very little is known about how individuals, in particular parents, decide to become voluntary coaches. The research set out to test if a quantitative model could represent such a decision process. It formulates a model of the process and tests the model against field data. From Social Exchange Theory, a conceptual model was developed of the decision process to enter a coach education programme. It was clear that the process was multi-dimensional. The research then showed how this multi-dimensional conceptual model could be mathematically represented by a logistic regression model. Published work on volunteering, sport and coaching was reviewed. From this literature review, a set of potential explanatory variables was obtained which previous researchers had suggested to be involved in decision processes involving volunteering and coaching. Hypotheses were made for these potential explanatory variables. Data was collected by personal interview of a sample of 112 individuals associated with athletics in the UK. The sample was taken from qualified, voluntary athletic coaches, from adult members of two amateur athletic clubs, and from parents of children in these clubs. The building of the logistic regression model showed the relative importance of each of the explanatory variables to the decision process. It also showed whether or not variables were independent or associated with another variable. Tests were conducted to indicate how well the mathematical model fitted the data and, hence, how well the conceptual model represented the sample. The use of logistic regression allowed the potential explanatory variables to be ranked in order of influence on the decision to become a coach. It also allowed the hypotheses to be tested. Qualitative information was also obtained from the interviews. These allowed the logistic regression model to be triangulated. The qualitative data gave further insights into the perceptions of adults, especially parents, and of coaches. It also indicated the key events which triggered a decision to coach. The logistic regression model provided a satisfactory fit to the data indicating the adequacy of the conceptual model. It indicates that the two genders have differing sets of significant explanatory variables. Some variables were found to be more complex than suggested by the published literature, others to be non linear and some not significant. The degree of fit suggested that one or more unknown, but significant, variables still need to be identified. The research suggests how the models could be improved and developed. There are implications for the future recruitment, training and retention of voluntary athletic coaches. By extension, the conceptual and mathematical models can be adapted for other adult education decision processes where the choice of course is voluntary.

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