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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.

Isokinetic muscular strength and performance in youth football : relationships with age, seasonal variation and injury

Forbes, Hollie Samantha January 2012 (has links)
The primary aim of the current project was to investigate the isokinetic muscular strength and performance of elite male youth footballers, and the relationships with age, seasonal variation and injury. A secondary aim was to use the information gathered to target muscle strain injury prevention strategies to particular age groups and times, and evaluate the effect. The primary aim was achieved by establishing normative patterns for muscular strength and performance of elite male youth footballers (grouped according to chronological and biological age) across a competitive season of youth football in Chapters Four and Five. Isokinetic muscular strength (characterised by peak torque (PT) and peak torque relative to body weight (PTBW)) of the hamstrings (H) and quadriceps (Q) using both concentric (CQ, CH) and eccentric muscle actions (EH) was evaluated. Muscular performance of the same muscle groups (characterised by H:Q ratios (conventional (CHQ) functional (FHQ)), asymmetry (dominant (dom):non dominant (ndom) leg ratios (e.g. CQ:CQ)), and angle of peak torque (AoPT)) was also investigated which necessitated an isokinetic speed of 60 °/s. Isokinetic evaluation was completed three times over the course of a regular playing season (start of season (SS) mid season (MS) and end of season (ES)). Participants were grouped according to chronological age (n=152, under 12 (U12) - under 18 (U18)) and biological maturation (according to Pubertal Development Scale (PDS 1 - 5) n=134). Forty seven participants completed SS, MS and ES isokinetic evaluation. Bilateral isokinetic evaluation consisted of five maximal repetitions of CQ and CH, followed by five repetitions of EH, leg dominance was counter-balanced. Repetitions two-four were used to calculate PT, PTBW, dom:ndom and AoPT for CQ, CH and EH, CHQ and FHQ; these measures were compared across chronological and biological age groups using a mixed model ANOVA. Dom:ndom CQ, CH and EH were compared across chronological and biological age groups using a one way ANOVA, while the relationship between AoPT and PT/PTBW was considered using a Pearson’s correlation. Additionally, the relationship between chronological and biological age, and PT/PTBW was investigated using a mixed model ANOVA within PDS group three. For analysis of seasonal variation a mixed model ANOVA was applied for all isokinetic measurements which considered time (SS, MS, ES), leg dominance (dom, ndom) and age group (U12 -U15) with a further mixed model ANOVA performed on CQ:CQ, CH:CH and EH:EH. Where appropriate SIDAK corrections were applied and the level of significance was accepted at p≤0.05. The main findings were that youth footballers did not increase their PT and PTBW EH in-line with CQ and CH as chronological and biological ageing progressed, this lead to a significant FHQ imbalance at U18. Dom:ndom CH comparisons identified that the chronologically younger and biologically less developed groups displayed a significantly stronger dom leg which may be explained through the concepts of skill acquisition and trainability. Biological age was not found to exert any additional effect over and above that of chronological ageing as significant differences in muscle strength still existed according to chronological age group within PDS group three. Additionally, AoPT EH and PT EH were found to be significantly negatively correlated on both legs which supported a potential mechanism for non contact hamstring muscle strain injury during running. Analysis of seasonal variation revealed that all PTBW measures showed a MS decrease. This may be related to breaks in normal training activity and links appropriately to times of peak injury incidence highlighted in youth football. In order to achieve the secondary aim of the current project Chapters Four, Five and Six investigated the relationship between isokinetic muscular strength and performance, muscle strain injury of the thigh, and injury risk attenuation. A retrospective and prospective injury audit was undertaken for the elite male youth football participants. For the retrospective approach participants were grouped according to chronological age (n=147) or biological age (n=128) and indicated using a self-report injury form their history (ever, (Hx)) or recent history (12 months, (Hx12)) of hamstring, quadriceps and adductor injuries. Approximately each player had an Hx of muscle strain injury and 0.56-0.59 of players had an Hx12. The hamstrings were the most commonly injured muscle group and the prevalence of muscle strain injury Hx and Hx12 increased with chronological and biological age. The prospective audit (n=50) identified that 0.16 of players sustained a muscle strain injury during the season, 0.08 of these being to the hamstrings. Between group comparisons (one way ANOVA with SIDAK correction) were also performed to investigate the difference in isokinetic measures between those participants who had an Hx12 of muscle strain injury and those who did not. It was discovered that for Hx12 of an injury to the dom hamstrings the injured group had less PTBW CH and EH on the dom leg. The injured group also had more inner range AoPT CH. These findings linked appropriately to the reported mechanisms and risk factors for hamstring injury but the exact direction of cause and effect could not be established. To this end a logistic regression analysis was undertaken in an attempt to predict which group (injured vs. non injured the 50 participants would belong to, using evidenced based risk factors in the experimental model. No predictive relationship between risk factors (including altered isokinetic muscular strength and performance) could be established. The information regarding the relationship between injury and muscular strength and performance may highlight a role for isokinetic screening to ensure adequate rehabilitation from injury. Injury risk attenuation strategies were investigated through an exercise intervention using the U18 age group following a break from football activity. The participants were split based on their FHQ at initial isokinetic evaluation (via odd and even placing) to form control (n=8) and intervention groups (n=8). Isokinetic evaluation was conducted as previously outlined and the exercise intervention targeted the hamstrings. Only six of the control group and seven of the intervention group completed the study and were compared using a mixed model ANOVA. Results showed that the intervention group were not significantly different to the control group post intervention for any of the isokinetic muscular strength and performance measures, though both groups significantly improved over time for the ndom leg CHQ and PTBW EH, and FHQ improved for both legs. Contamination of the control group may explain the lack of significant difference between groups. However, the exercise intervention was not targeted to individuals who displayed prior alterations to isokinetic muscular strength and performance, and this approach was discussed using the results of one member of the intervention group. In summary, the current project achieved the stated aims by discovering normative patterns of isokinetic muscular strength and performance according to age and seasonal variation. Injury risk attenuation strategies were targeted appropriately to the U18 age group following a break from football activity. However, the applied evidence based exercise may have been more effective if targeted to ‘risk’ after isokinetic screening.

A transtheoretical model intervention to help Greek students adopt and maintain a physically active lifestyle

Tzormpatzakis, Nikolaos January 2012 (has links)
Physical activity is positively related to a number of health benefits that influence morbidity and mortality during childhood, adolescence and adulthood. However, an epidemic of physical inactivity is quickly expanding worldwide and particularly affecting the Greek population. Early life periods and especially transitional ones leading to young adulthood are considered critical to intervene to help people adopt and maintain an active lifestyle. Well-designed longitudinal interventions are recommended for these ages. The main objective of this study was to design, implement and assess an intervention to help students adopt a more active profile according to the Transtheoretical model. This theory was selected due to its practicality and adaptability. The intervention materials consisted of a set of five printed manuals based upon the Transtheoretical model and encouraging physical activity. The study design was quasi-experimental (n=665, mean age=15.8 years, 57% girls) with a stratified assignment of the intervention (nInt=263) and control group (nCon=402). The intervention consisted of the administration of one printed manual to each student according to his/her current stage and its use for the next four months. Greek secondary students were measured longitudinally in the course of three years extending from two years before their graduation until one year after their graduation. The first two measurements were performed in the second grade of Lyceum (Greek high school) one just before and one just after the intervention. The last two measurements were conducted one year after and two years after the intervention. The research questionnaires measured stages of change, processes of change, decisional balance and self-efficacy, which are the main components of the Transtheoretical model. These instruments assisted firstly with the implementation and secondly with the assessment of the intervention. The research hypotheses examined the various intervention effects. The main analysis of the stage data was performed with latent transition analysis, which was considered as appropriate and advantageous. The latent stage results revealed positive intervention effects in the short-term, which were neutralised in the mid- and long-term. A comparison of the observed stage data pre- and post-intervention confirmed that in the short-term the intervention had successfully helped more students to progress and fewer students to regress along the stages of change continuum compared to the control group. Regarding self-efficacy, decisional balance and processes of change, within-group longitudinal comparisons of the observed data disclosed positive comparative short-term effects. In general, these effects were also reversed or neutralised in the midterm and remained neutral in the long-term. In most cases the above-mentioned trends of the whole sample were also confirmed for each gender separately making the intervention successful only in the short-term. Several shortcomings identified in the literature were addressed by the current study by implementing a longitudinal design, conducting a long-term investigation of the intervention effects and specifically adapting and validating the research instruments for the studied population. The “less is more” approach encapsulates the philosophy behind this intervention. In fact, the resources used were kept in a minimum regarding students’ time and schools’ involvement. Together with the easiness of the administration of the intervention contributed to the potential of being easily generalisable to wider populations. Additionally, the development and implementation of the Greek adolescent stages of change manuals was a pioneer work for Greece. It is recommended that a number of successive interventions be implemented to accomplish a longer duration of positive results. Another recommendation was to expand the public impact of this intervention by attempting it on a larger, even national scale and in different settings. Finally, the positive conclusions of the current study confirmed its success in helping young people adopt and maintain an active lifestyle and also it provided similar future studies with validated tools and added experience to continue in the search for more efficient PA interventions.

The psychology of anterior cruciate ligament injury rehabilitation amongst professional rugby union players

Carson, Fraser January 2012 (has links)
[From the introduction:] Within professional contact sports, injury has been reported frequently by athletes as causing stress (Anshel, 2001; Noblet & Gifford, 2002). Particularly within rugby union where injury has been reported as one of the top four stressors experienced by elite adolescent players (Nicholls & Polman, 2007), and the most frequent stressor by adult professional players (Nicholls Holt, Polman, & Bloomfield, 2006). A variety of coping strategies are utilized to manage these stressors, with the effectiveness varying per player (Nicholls et al., 2006). Although to date no research has found a causal relationship between injury as a source of stress and the actual incidence of injury such research suggest that injury can significantly increase the stress experienced by athletes. This is supported by the findings that following serious sports injury, elite athletes have reported this to be a stressful experience (Gould, Udry, Bridges, & Beck, 1997a) which is manifested by concerns related to career, physical rehabilitation, social interactions, further injury, and return to prior performance levels (Gould et al., 1997; Tracey, 2003).

Training load monitoring in soccer : the dose-response relationships with fitness, recovery and fatigue

Akubat, Ibrahim January 2012 (has links)
The congested fixture schedules in elite soccer leagues around the world has bought the issue of recovery between games and subsequent performance to the fore in soccer related research. Studies have described the time-course of recovery for numerous biochemical and physiological measures of performance, fatigue and recovery from match-play. However, the research also suggests that there is individual variation in the external load both between players and between matches. The external load measured as distance in match-play has been shown to vary by ~30% between games. However it is the internal training load that will determine the magnitude of the physiological responses on an individual basis. Therefore the major aim of this thesis was to examine the dose-response relationships between measures of training load and the physiological and biochemical responses used as markers of recovery from match-play. The thesis also assessed the relationships between these proposed markers of recovery and soccer specific performance. In meeting the aims of the thesis a number of preliminary studies were conducted. The study in section 3 assesses the extent of fixture congestion in the English Premier League. The results showed over 30% of games for the most successful teams are played with 3 days recovery time, justifying the need for investigating recovery from soccer match-play. Given the variation in soccer match-play section 4 examines the reliability and validity of the modified BEAST90 soccer simulation. A measure of performance with less variance would allow changes in soccer specific performance to be identified with greater certainty in section 7. Section 5 assesses the influence of intermittent exercise on the blood lactate response. Given that the new iTRIMP method of measuring internal training load weights exertion with the blood lactate response it was important to assess the influence exercise mode may have on the calculation of internal training load. The results showed that at higher intensities intermittent exercise produced significantly higher blood lactate responses. Section 6 assesses the dose-response relationships between training and fitness using numerous measures of internal training load over a 6 week training period. The results showed only the iTRIMP method showed a significant relationship with changes in fitness. Section 7 assesses the dose-response relationships between exertion in soccer match-play and various physiological measures of fatigue and recovery. The relationships between these measures and changes in soccer specific performance were also assessed. Finally the internal and external load were integrated and the relationships of this ratio assessed with measures of fitness and performance. The results showed that changes in any of the physiological and biochemical measures used to assess recovery did not relate to changes in performance with the exception of testosterone which showed significant positive relationships with changes in distance covered from the 1st trial of the modified BEAST protocol to 2nd. Testosterone also was the only measure to show a significant relationship during the recovery period with any measure of training load (sRPE). Finally, the novel findings of this thesis is the relationships between the integrated ratio’s of internal and external training load with measures of aerobic fitness is also presented in section 7. The studies provided in this thesis have made a major contribution in demonstrating how data that is routinely collected at elite levels of soccer can be used more appropriately. It has also shown limitations of some the methods currently employed to measure training load. Furthermore changes in many of the markers used to assess recovery of soccer players do not seem to relate to changes in soccer specific performance. This may point to a change in paradigm which is required in both research and practice.

Understanding community coaches' experiences of everyday coaching practice : a narrative-biographical study

Gale, Laura January 2013 (has links)
No description available.

Acute post-exercise cardiovascular responses in healthy participants

Reynolds, Linda J. January 2013 (has links)
The overall aim of this project was to investigate the acute cardiovascular post-exercise response in healthy individuals. The aim of the first study was to establish the within day and between day reproducibility of supine and tilt baroreflex sensitivity (BRS) utilising time (sequence) and spectral indices in 46 healthy adult males employing three repeat measures; baseline, + 60 min and + 24 h. Reproducibility was assessed by the 95% limits of agreement (LOA) to assess the extent of agreement and an alternative approach of estimating the technical error of the measurement (TEM) to assess reproducibility was also undertaken. The LOA indicated same day reproducibility was marginally better than between day reproducibility for spectral parameters while between day reproducibility was marginally better than same day reproducibility for sequence parameters with reproducibility markedly improved across all BRS outcome measures during tilt. Precision expressed by TEM for all spectral outcomes was good in both supine and tilt BRS (< 6 %) although precision was lower, but acceptable, for sequence BRS outcomes in both positions (< 11%). Thus, all BRS outcome measures and the tilt procedure were incorporated into the exercise study. The aim of the second study was to compare the response of supine and tilt BRS following a single bout of moderate intensity exercise and high intensity exercise. Further details are given in the full abstract above.

Exercise behaviour change among a sample of Malay students living in northern England : an application of the transtheoretical model

Omar Fauzee, Mohd Sofian Bin January 1999 (has links)
This programme of research was concerned with an examination of the exercise behaviour change of a sample of Malay students living in five different cities in Northern England (Bradford, Leeds, Manchester, Newcastle-upon-Tyne and Sheffield). The research methods used were a cross-sectional study (Study 1), an in-depth interview (Study 2) and a longitudinal study, divided into two parts - quantitative (Study 3A) and qualitative (Study 3B). These three studies were conducted in order to answer four main Research Questions: I. To what extent is Prochaska and DiClemente's (1983)Transtheoretical Model usefuli n examiningt he exerciseb ehaviouro f the students? A cross-sectional study (Study 1) was employed to answer the first research question. The respondents (N = 123) were drawn from two annual meetings of the Malaysian Students Societies at Leeds Metropolitan University and Leeds University. The results showed that there was a relationship between the stages of change and the processes of change, self-efficacy and decisional balance. On the basis of the findings of this initial study (Study 1), two new contributions to the field of exercise behaviour were made: a culture-specific exercise intervention programme was devised, and evidence was provided that the Transtheoretical Model is a wholly suitable vehicle for explaining the exercise behaviour of the students. 2. What factors influenced the exercise behaviour of the students? To answer the second research question, Study 2 (an in-depth interview) was employed, using 20 of the students from Study 1. Study 2 identified the factors that inhibit and those that enhance exercise participation. The nine inhibiting factors were: time constraints, attitude-related factors, lack of guidance, lack of exercise partner, lack of interest, poor weather, lack of child-care facilities, unhealthy physical condition and lack of experience. The five enhancing factors were: health and fitness, sociological factors, psychological benefits, good facilities and a history of exercise. The study also enabled the researcher to make three more contributions in the area of exercise behaviour. These were: the discovery of the "Proselytizing" stage, the fact that the Processes of Change Instrument fails to take into account "involuntary" factors and a proposal for revising the Stages of Change Instrument. 3. Is there any identifiable pattern of change in their exercise behaviour, over a period of time? Study 3A, which employeda longitudinals tudy,o ver an eight-monthp eriodw as able to provide an answer to the third research question. The respondents (N=110), Malay students newly-arrived in England, were contacted through the Malaysian Students' Societies in five different cities in Northern England (Bradford. Leeds. Manchester, Newcastle-upon-Tyne and Sheffield). There were three data collection during the eight-month period of investigation (baseline, follow-up and third data collections). The results revealed that the processes of change scores increased in the Adopters groups, decreased in the Relapsers group, and remained substantially the same in the Stable Inactive and Stable Active groups. Study 3A highlighted the limitations of the Processes of Change Instruments used in earlier studies and revealed that the Marcus et al., (1996c) method of identifying Adopters and Relapsers was inadequate. It also suggested that "Stable Preparers" group should be identified as an additional group, apart from Stable Active and Stable Inactives groups. 4. What are the factors that caused the newly-arrived Malay students to relapse from exercise the over four-month period? Thirty students who were found to have relapsed, in the follow-up data collection (Study 3A) were invited to participate in this study. Of the thirty students, nineteen agreed to participate in the qualitative, longitudinal study. Study 3B revealed that weather conditions, lack of time and lack of exercise partner were among the most prominent reasons why recently-arrived students relapsed from exercising. Furthermore, the study also demonstrated that cultural and religious differences contributed to their relapse from exercise. Recommendations for future research, in this area also, are advanced.

A comparative study of Pulguk-sa and Haein-sa temples as tourist destinations in Korea

Kim, Sang Mu January 1989 (has links)
Pulguk-sa and Haein-sa Temples, which are ~ical Buddhist temple destinations, are located in the south-east of the Korean peninsula and attract the highest number of tourists of the twothousand temples in Korea. Pulguk-sa is located in the Kyongj u National Park, and Haein-sa is in the Mount Kaya National Park. Both temple sites have been designated officially as Historic and Scenic Sites by the Korean Government. This thesis examines the total impact of tourism at these two important temples and in so doing draws out a number of p::>licy recommendations to improve them as tourist destinations. To carry out the research, surveys were undertaken which incorporated the business community, the monks and the visitors at the temple sites, together with numerous face to face interviews with the temple authorites and local and national government officials. In addition to providing much qualitative information, the surveys made possible the construction of local Input-output models to assess the economic impact of tourism. In this manner an overall perspective of the tourism demand and supply situation at the two temples was obtained which enabled comparisons to be made, the economic importance of tourism to be identified, and development priorities to be listed

Why we're all going on a summer holiday : the role of the working-class organisations in the development of popular tourism, 1850-1950

Barton, Susan January 1999 (has links)
No description available.

The influence of perfectionism on social physique anxiety

Petherick, Caroline Margaret January 2002 (has links)
Activity promotion advocates regular exercise as a way of reducing mortality, thus providing a cost-effective strategy for public health improvement. However, many individuals embarking on a regime have unpleasant experiences and are more likely to withdraw. One construct identified in the literature that may contribute to this negative affect is social physique anxiety (SPA; Hart et al., 1989). Although the correlates and consequencesa ssociatedw ith SPA have provided invaluable insight, there still lacks conceptual focus. Therefore, adopting the tenets of Lazarus (1999), one individual difference factor important in the cognitive appraisal process that may contribute to SPA is perfectionism (Hewitt & Flett, 1991). This motivational construct has been found to influence the appraisal process and predispose individuals to experience anxiety. Therefore, the purpose of Study 1 was to firstly, investigate the influence of individual differences in perfectionism on SPA and to secondly, explore the mediating influence of coping strategies on SPA, threat, and levels of enjoyment among beginner exercise class participants. In the first part of Study 1, four hundred and four (376 females, 28 males) participants completed measures of social physique anxiety, perfectionism, ability, importance, capacity beliefs, self-efficacy, threat, and enjoyment. In the second part of Study 1, only those participants who deemed that being good at exercise was important to them (N = 317) were used in the analyses. Path analyses results using structural equation modelling procedures provided adequate support for the first part of Study 1 (x I /df = 2.41, BBNNFI = 0.96, Robust CFI = 0.99), and little support for the second part of Study 1 (x2/df = 7.87, BBNNFI = 0.66, Robust CFI = 0.77). Although the research has acknowledged the importance of secondary 11 appraisal characteristics as contributing to threat, the importance of differing motivational orientations as contributing to variations in cognitions and affective responses (Deci & Ryan, 1985) may be equally important. Therefore, in addition to Study 1, the purpose of Study 2 was to investigate the influence of perfectionism on levels of self-determination (Deci & Ryan, 1985), SPA, threat, and enjoyment through the mediational role of perceived competence and autonomy. In addition to the measures used in Study 1, two hundred and eighteen participants (192 females, 26 males) further completed a measure of locus of causality for exercise and a measure of regulation in exercise behaviour. Path analyses results provided little support for Study 2 (x 2/df= 11.85, BBNNFI = 0.23, Robust CFI = 0.27). Overall, the results from the second part of Study 1 and Study 2 provide little support for the hypothesised relationships due to the overall poor fit of the models found. However, the results of the first part of Study 1 provided adequate fit indices suggesting that socially prescribed perfectionism more than self oriented perfectionism influences SPA. In turn SPA significantly and negatively influenced self-efficacy as would be expected. Furthermore, both self-efficacy and capacity beliefs significantly and positively influenced exercise enjoyment. The importance of investigating perfectionism and other individual difference factors as antecedents of SPA are discussed, and future research recommendations proposed. 111

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