The central nervous system is highly sensitive to reductions in oxygen availability but the neurophysiological responses in healthy human lowlanders are not well understood. In severe hypoxia, whole-body exercise tolerance is impaired and neuromuscular fatigue, defined as any exercise-induced reduction in the ability of a muscle to generate force or power, reversible by rest, may be largely due to cerebral perturbations. The primary aim of this thesis was to determine the mechanisms of exercise-induced neuromuscular fatigue and the related neurophysiological responses to acute, chronic and intermittent severe hypoxia in healthy humans. In acute severe hypoxia (AH), exercise tolerance was, in part, mediated by a hypoxia-sensitive source of central fatigue, measured as a decrease in voluntary activation (VA) of the knee extensors (Study 1 – 4). This coincided with a significant challenge to systemic (arterial oxygen saturation [SpO2] ≈ 70%, Study 1 - 4) and cerebral oxygen availability at end-exercise (Study 3 - 4). The rate of development of peripheral locomotor muscle fatigue was blunted at task failure in AH in comparison to normoxia (Study 1 – 2). Corticospinal excitability and the neuromuscular mechanisms of fatigue were measured after a prolonged (two-week) exposure to high altitude in Study 3 (5260 m above sea level, Mount Chacaltaya, Bolivia). This was the first study to show that acclimatisation to chronic severe hypoxia (CH) alleviates the development of supraspinal fatigue induced by whole-body exercise in AH. This occurred in parallel to an improved cerebral oxygen delivery and cerebral oxygenation. Interestingly, the neurophysiological responses at rest in CH were characterised by an increased corticospinal and muscle membrane excitability. The peripheral contribution to neuromuscular fatigue was not attenuated following acclimatisation to high altitude. In study 4, a two-week protocol of intermittent hypoxia (IH) attenuated exercise-induced supraspinal fatigue measured in AH and substantially improved constant-power cycling in severe hypoxia. Total haemoglobin mass was unaltered by IH, but arterial oxygen content was improved due to an increase in SpO2, secondary to an enhanced ventilatory response to exercise. Peripheral locomotor muscle fatigue was lower following IH, which may be related to exercise training in hypoxia. Although corticospinal excitability was unchanged following a single 2-h exposure to severe hypoxia, repeated exposures of IH resulted in a transient increase in motor cortex excitability without changes in intracortical inhibition. (Study 5). In conclusion, in acute severe hypoxia, whole-body exercise tolerance is impaired through oxygensensitive mechanisms which exacerbate central fatigue. The acute response can be alleviated following both chronic and intermittent severe hypoxia.

Prolonged moderate intensity cycle exercise is associated with a gradual and progressive reduction in gross efficiency (GE). It was speculated that this loss of GE might reflect a reduction in maximal muscle function and result in a parallel decline in aerobic performance. The effect of prolonged moderate intensity cycle exercise on maximal muscle function and anaerobic performance has not been clearly established. This thesis examined the impact of 1-2 h of cycling exercise at 60-65% maximal aerobic power in well-trained cyclists on subsequent changes in aerobic and anaerobic performance, GE and maximal muscle function.

The current work is novel in that it investigated in vivo analysis of glucose metabolism during and following hypoxic exposure in type 2 diabetics. Using moderate levels of hypoxia, study one found that 60 min of resting hypoxic (Hy Rest) exposure reduced blood glucose concentrations in type 2 diabetics. Insulin sensitivity was also found to be significantly greater following hypoxic exposure when compared to the normoxic control. The second study showed that exercise under hypoxic (Hy Ex) conditions acutely reduced arterialised blood glucose concentrations. The total area under the curve for insulin was also significantly lower subsequent to an intravenously administered glucose load (IVGTT) in the 4 hr following Hy Ex versus normoxic exercise. The third study demonstrated that glucose disposal was acutely enhanced in exercise bouts lasting 60 and 40 min (of equal work) in hypoxia.

This thesis investigates the England Visually Impaired Cricket Team, whose squad members comprise sixteen men aged 18-54, and their lived experiences' of playing visually impaired cricket. This is the first piece of research to examine elite visually impaired cricket and the first to explicitly analyse the social dynamics of any visually impaired sports team. Through an embodied theoretical approach, that accounts for the corporeal experience of impairment alongside the role of social institutions and discourse in the high performance culture of modern disability sport, this thesis establishes the significant aspects of this previously unexamined research 'site', both on and off the pitch. This study consisted of ten months of ethnographic fieldwork using participant observation and semi-structured interviews shaped by a new method of recording and eliciting data. To capture the participants' sensorial experiences of playing visually impaired cricket, 'soundscape elicitation', the process of composing auditory 'tracks' of the players' participation and then using these recordings during semi-structured interviews to prompt sensorial discussions, was utilised. This original and innovative method was central to the production of previously unexamined knowledge and is a significant methodological advancement in the wider field of sensory studies. The findings present a number of original contributions to knowledge regarding 'sporting bodies', the sensorial experiences of sport, and the construction of identity through disability sport. The participants' embodied experiences of playing visually impaired cricket reveal an alternative way of 'being' in sport and physical activity. However, it is the inescapable ocularcentric value of 'sight' that inhibits the resistive potential of the game. Instead of the presumed empowering experience, elite visually impaired cricket is disempowering for many participants due to the irreversible relationship of blind cricket institutions with mainstream cricketing bodies. Furthermore, a 'hierarchy of sight' based upon the official sight classification process emerges that highly values those players with the highest sight classifications and marginalises the blind players. All of these factors inform visually impaired cricket players’ construction of their own identities. Although many players view visually impaired cricket as a way of demonstrating their 'normality', it actually accentuates the impairment that they are attempting to dissociate from and is one of the few social situations where they are 'outed' as disabled or blind.

Prefrontal cortex is frequently linked to dual-task gait performance; however, its precise role is unknown. The purpose of this thesis was to examine the role of prefrontal cortex in the control of dual-task gait. Using transcranial direct stimulation (tDCS) to alter prefrontal cortex activity, the influence of prefrontal cortex on dual-task gait performance and the corticospinal system was examined across four experiential studies using the guided activation framework of prefrontal cortex function (Miller and Cohen, 2001). The first study examined the role of cognitive task type and walking speed on stride time variability and trunk range of motion during dual-task walking. Results revealed the greatest dual-task cost on gait occurred when walking at a slow speed whilst simultaneously performing a serial subtraction task, compared to performance of a working memory task, providing a rationale for the use of this paradigm in later studies. The second study examined the effect of prefrontal tDCS on dual-task gait performance during both normal and slow walking. Anodal tDCS reduced the dualtask cost on both gait and cognitive task performance, and these effects were not dependent on walking speed. These results indicating that prefrontal tDCS may alter the allocation of cognitive control across tasks during dual-task gait, in accordance with established models of prefrontal cortex function. The third study examined the effect of prefrontal tDCS on corticospinal excitability and working memory performance. Results revealed that cathodal tDCS reduced corticospinal excitability. However, there was no effect of tDCS on working memory performance. Because prefrontal tDCS altered the activity in remote motor networks, these results indicated a possible mechanism by which prefrontal cortex exerts control over gait performance. In addition, because this study failed to replicate previous reports of working memory improvement following tDCS, these results also suggested a degree of inter-individual variability in response to tDCS. The final study examined the influence of walking modality and task difficulty on the effects of prefrontal tDCS on dual-task gait performance. tDCS altered the allocation of cognitive control during over-ground dual-task gait performance, and 3 these effects were mediated by task difficulty. In contrast to the second study, there was no effect of tDCS on treadmill dual-task gait. A secondary aim of the final study was to examine whether cognitive and walking task performance were coordinated. Results revealed that participants articulated answers during the initial swing phase of the gait cycle more frequently than other phases, indicating a degree of coordination between the performance of these tasks. Overall the finding of this thesis indicate that prefrontal cortex is involved in the allocation of cognitive control processes during dual-task walking, in accordance with the guided activation and flexible hub accounts of frontal cortex function (Miller and Cohen, 2001; Cole et al., 2013). These findings may have implications for the design and validation of strategies aimed at improving the cognitive control of gait.

The development of talent is a complex process mediated by a host of psychology, social, physical, and environmental variables. Unfortunately, the multiple processes involved in talent development (Gagne, 2004; Simonton, 2001) are frequently ignored by the systems and protocols employed in sport. Modem approaches to talent development are beginning to stress the initial possession, then subsequent development, of Psychological Characteristics of Developing Excellence (PCDEs; MacNamara, Button, & Collins, 2010) as the best way to realize latent potential. Accordingly, the aim of this thesis was to acknowledge this complexity by identifying the psycho-behavioural factors that co-act with physical potential and practice regimes to enhance the efficacy of TID models in sport. The main objectives of this thesis were: 1. To identify the challenges faced along the pathway to excellence and the PCDEs that facilitate the successful negotiation of the pathway to excellence across different performance domains. 2. To identify whether PCDEs are operationalised differentially depending, on an individual's age, stage, and context. 3. To confirm these differential roles through quasi-longitudinal examinations of longterm employment (in musicians) and across a key transition (in athletics, the transitions to university at 18 years of age). 4. To develop a questionnaire to bridge the theory-practice divide in TO processes and enable formative evaluation of PCDEs by practitioners. 5. To provide preliminary validation of the questionnaire by evaluating its discriminant function between good and poor development athletes. The development of talent is a complex process mediated by a host of psychology, social, physical, and environmental variables. Unfortunately, the multiple processes involved in talent development (Gagne, 2004; Simonton, 2001) are frequently ignored by the systems and protocols employed in sport. Modem approaches to talent development are beginning to stress the initial possession, then subsequent development, of Psychological Characteristics of Developing Excellence (PCDEs; MacNamara, Button, & Collins, 2010) as the best way to realize latent potential. Accordingly, the aim of this thesis was to acknowledge this complexity by identifying the psycho-behavioural factors that co-act with physical potential and practice regimes to enhance the efficacy of TID models in sport. The main objectives of this thesis were: 1. To identify the challenges faced along the pathway to excellence and the PCDEs that facilitate the successful negotiation of the pathway to excellence across different performance domains. 2. To identify whether PCDEs are operationalised differentially depending, on an individual's age, stage, and context. 3. To confirm these differential roles through quasi-longitudinal examinations of longterm employment (in musicians) and across a key transition (in athletics, the transitions to university at 18 years of age). 4. To develop a questionnaire to bridge the theory-practice divide in TO processes and enable formative evaluation of PCDEs by practitioners. 5. To provide preliminary validation of the questionnaire by evaluating its discriminant function between good and poor development athletes. The development of talent is a complex process mediated by a host of psychology, social, physical, and environmental variables. Unfortunately, the multiple processes involved in talent development (Gagne, 2004; Simonton, 2001) are frequently ignored by the systems and protocols employed in sport. Modem approaches to talent development are beginning to stress the initial possession, then subsequent development, of Psychological Characteristics of Developing Excellence (PCDEs; MacNamara, Button, & Collins, 2010) as the best way to realize latent potential. Accordingly, the aim of this thesis was to acknowledge this complexity by identifying the psycho-behavioural factors that co-act with physical potential and practice regimes to enhance the efficacy of TID models in sport. The main objectives of this thesis were: 1. To identify the challenges faced along the pathway to excellence and the PCDEs that facilitate the successful negotiation of the pathway to excellence across different performance domains. 2. To identify whether PCDEs are operationalised differentially depending, on an individual's age, stage, and context. 3. To confirm these differential roles through quasi-longitudinal examinations of longterm employment (in musicians) and across a key transition (in athletics, the transitions to university at 18 years of age). 4. To develop a questionnaire to bridge the theory-practice divide in TO processes and enable formative evaluation of PCDEs by practitioners. 5. To provide preliminary validation of the questionnaire by evaluating its discriminant function between good and poor development athletes. To address the first and second objective, Chapter 3 describes a retrospective, qualitative study of the careers of elite performers. The findings of this study suggest that the pathway to excellence is complicated by the specific challenges faced within different performance domains. However, a similar set of PCDEs, albeit differentially deployed, were reported by all participants as facilitators of development. Chapters 4 and 5 employed a quasi-longitudinal research design to address Objective 3 - the differential deployment of PCDEs in particular contexts. Using a sliding populations methodology, young classical musicians were tracked over a 2-year period to explore the PCDEs employed during the macro and micro stages they encountered as they progressed. A similar research design was employed in Chapter 4 to examine the use of PCDEs during a critical transitional period for track and field athletes. Although the results point to the generality of PCDEs at both elite and developmental levels, and across performance domains, there appeared to be an understandable and necessary shift in responsibility from significant others promoting and reinforcing PCDEs in the early years towards self-initiated and autonomous behaviours in the later years; in essence, a shift in the source of regulation (Cleary & Zimmerman, 2001). The studies in Chapters 3, 4, and 5 generated a list of PCDEs that facilitated development, along with an understanding of how PCDEs were deployed differentially along the pathway to excellence. These findings were used to develop the Psychological Characteristics of Developing Excellence Questionnaire (PCDEQ); a questionnaire designed to assess the possession and strategic deployment of the PCDEs. Chapter 6 reported the systematic generation of questionnaire items and an exploratory factor analysis that resulted in a 59- item, 6 factor stnicture PCDEQ. The PCDEQ displayed good psychometric properties and should provide coaches with a theoretically and empirically supported tool to assess, monitor, and develop these key developmental skills. To address the final objective, Chapter 7 presents a discriminant function analysis which revealed that the PCDEQ had very good discriminant function and was able to classify between 67 per cent and 75 per cent of athletes correctly on the basis of their self-reported behaviour in sport. In conclusion, the studies reported in this thesis provide a significant contribution to current knowledge by shifting the fopus away from TID methods based on prediction and correlation towards a consideration of progress and behaviour during development. Future recommendations include the need for further validation of the PCDEQ as well as longitudinal and action-based research assessing the role of PCDEs in talent development.

'Cycling is one of the toughest sports and one of the most complex to analyse in scientific terms.' - Mr Hein Verbruggen,P residentU nion Cycliste International 1991-2005. Despite extensive research into sagittal plane lower limb cycling kinematics there is little scientific literature available investigating the three-dimensional joint kinematics of the cyclist, and especially so regarding the kinematics of the pelvis, trunk, and arms, and how these are affected by workload, upper body posture, and saddle setback. This Thesis developed a comprehensive full-body three dimensional kinematic model and then determined the effects of workload, Upper Body Posture, and Saddle Setback on the leg, trunk, and arm kinematics of the cyclist. Competitive cycling has an extremely high aerobic component, and yet ironically there have been few studies investigating how workload or riding position affect lower limb blood flow haemodynamics. By using Near-Infrared Spectroscopy a cycling specific technique was developed to enable tissue oxygenation status of the lower limbs to be determined during cycling, which was then used to assess the effects of workload, trunk and hip angle, and saddle set-back on lower limb blood flow haemodynamics. It is unclear to what extent saddle setback affects lower limb and trunk muscle activity and cycling performance, and yet the sub-disciplines of cycling use markedly different bicycle set-ups. By using a custom cycle ergometer developed by the author this Thesis systematically assessed the effects of saddle setback on muscle recruitment and activation magnitude. When investigating the effects of bicycle set-up on cycling performance it is important to consider all the physiological and biomechanical determinants of success in unison, and how they inter-relate. To date there are no studies that have comprehensively studied the kinematic, haemodynamic, electromyographic, and associated crank kinetics simultaneously. As such this Thesis developed a methodology to evaluate the effects of changing workload, upper body posture, and saddle setback on fullbody three-dimensionalk inematics, lower limb blood flow haemodynamicsl,e g and trunk electromyography, and crank torque profiles, in order to arrive at the optimum riding position and highlight the compromises required when aiming to maximise cycling performance. The effects of workload were assessed by undertaking a 25W. min" graded maximal exercise test to exhaustion. In order to assess the kinematic, haemodynamic, and electromyographic effects of altering riding position a custom independently adjustable cycle ergometer was developed to permit precise accurate adjustment of the four main macro settings (saddle height and setback, and saddle to handlebar reach and drop) while maintaining the spatial coordinates of the other parameters. Three Upper Body Postures (Hoods,D rops and a Time Trial position), and six SaddleS etbacksw ere used (100,50, and Omm behind the bottom bracket, and 50,100, and 150mm in front of the bottom bracket). For all three studies three-dimensional full body kinematics were recorded using a stereophotogrammetricin fra-red motion capture system. Leg and trunk muscle activity were recorded using an 8-lead surface electromyographic system, and tissue oxygenation levels were recorded using Near Infrared Spectroscopy on the Vastus Lateralis. Corresponding crank torque profiles were measured simultaneously using a crank dynamometer. Increasesi n workload produced progressived ecreasesin Oxyhaemoglobina nd pedalling smoothnessin dex, and continual increasesin total haemoglobinc ontenta nd muscle activity in the majority of muscle groups, but produced little change in full-body kinematics until 80% maximal aerobic power was surpassedC. hanging from the Hoods to the Drops and into a Time Trial position had little effect on lower and upper limb kinematics, but produced significant increases in all lower limb muscle activity except the gluteus maximus, as well as considerable reductions in tissue oxygenation status, and resulted in cyclists pedalling with greater peak torque values. Moving the saddle forwards significantly affected joint kinematics, muscle activity, tissue oxygenation status, and the crank torques profiles. A saddle positioned with the nose directly over the bottom bracket minimised angular rotations of the ankle, knee, hip, and trunk as well as global muscle activation. Tissue oxygenation status was also significantly higher using this setting, suggesting that although an aerodynamic cycling position must take priority, setting the saddle with the nose directly over the bottom bracket and maintaining the operating range of motion at the hip and knee appears to maximise cycling performance, and that the spinal kinematics appear to act as a torque-induced engine by means of increases in axial rotation magnitude in the lumbar, mid-thoracic and thoracic spinal segments.

The focus of this project was to detect differences in running gait (at a fixed speed) induced by differences in shoes and surfaces. A review of the literature indicated that improvements in the measurement and analysis techniques were necessary to yield results accurate and reliable enough to. detect these differences. A pilot study was therefore performed to evaluate the magnitude of the measurement errors and the repeatibility of the results. One subject completed 98 trials (emcompassing 10 different shoe­surface conditions) at a fixed speed (approximately 4.46 m/sec) and the vertical (FZ) and horizontal (FY) ground reaction forces were measured. Parameters were developed ·to completely describe the characteristics of the ground reactions (FZ, FY). A statistical analysis performed using these parameters concluded that 10 trial repetitions were required for a reliable result. An X-ray study of one subject was also performed. This study evaluated the errors due to skin markers ( used for filming) moving with respect to the underlying bone. As a result of the X-ray study a new technique to reduce the marker motion errors was developed, tested and found to be potentially powerful. On the basis of the pilot study, the main experiment was designed to test five male subjects under four shoe-surface conditions. High speed films in conjunction with force platform data were collected. A two-dimensional model of the human leg was employed to yield resultant forces and moments at four joints (hip, knee, ankle and metatarsophalangeal). Parameters were developed to describe these resultants. The force parameters, joint resultant parameters and shoe /surface parameters (from friction, resilience and flexibility tests of the shoes) were correlated and discussed in relation to performance and injury potential. Methods of applying the conclusions to shoe and surface design were suggested.

This PhD thesis is concerned with sports tourism as a way of experiencing a sense of self, belonging and location in the social world. It is about how identity is developed, expressed and experienced when gymnasts interact within their specific sports community while travelling to take part in a non-competitive, international group gymnastics event. In particular, the research aim is to identify and make sense of the meaning participants attach to their involvement in sports event tourism in the context of the 2011 World Gymnaestrada in Lausanne/Switzerland, the purely non-competitive, official world event of the International Gymnastics Federation (FIG).

This thesis aimed to investigate physical education, physical activity and sport (PEPAS) participation and the adoption of health behaviours in Scottish adolescents. To address this topic, I start with a general reflection on the current state of Scottish health, through the lens of the Scottish and nested Glasgow effects. Subsequently, building on this conceptual base, I outline a series of three studies to further investigate the linkages between PEPAS and accumulating life stress and health behaviours. Accordingly, the thesis narrative consists of 4 distinct research outputs (1 desktop study, followed by 3 studies involving the collection of primary data). These studies were arranged as follows: In Chapter 4 (research study 1), I suggest that a confluence of social, environmental, attitudinal and cultural stressors may combine to negatively influence biological health. The core conclusion of this conceptual paper was that PA may provide a highly efficient, and cost-effective means to remediating some of the issues underpinning the Scottish effect. Chapter 5 (research study 2) presents data comparing patterns of PA uptake in adolescents of low socioeconomic status (SES) backgrounds with more affluent age-matched peers. SES is a significant biopsychosocial stress-elevating consideration. These findings add to mounting evidence suggesting excessively accumulating life stress, not only diminishes health, but simultaneously reduces PA uptake in vulnerable populations. The outcomes of this study thus emphasise the negative relationship between excessive life stress and PA, and highlight that there may be a bidirectional relationship between these factors. Chapter 7 (research study 3) qualitatively investigates the barriers and facilitators of PEPAS and exercise in the broad general education (BGE) phase of CfE in Scotland. Focus groups were conducted with 39 secondary school pupils (S1-S2). This study adds context-specific information highlighting the role of self-image, perceived competence and social influence on PEPAS participation. Subsequent findings indicated that the delivery of traditional PE lessons, which prioritise sporting ability, act as a participation barrier to pupils who consider themselves 'non-sporty'. Chapter 8 (research study 4) builds on Chapter 7 by qualitatively investigating why young people in the post 16 phase of CfE discontinue participation in exercise, sport and PA, whilst analysing reasons for this post compulsory education decline in PA. Previous negative PE experiences were perceived as a major barrier to continued PA. Furthermore, this young cohort perceived that PE teachers focused primarily on physically capable students. Respondents also perceived that access to contemporary fitness activities would be a positive option both during PE lessons, and as a tool to promote lifelong PA. Key conclusions emanating from this thesis included: PA levels were significantly lower in those who had experienced greater accumulated life stress. Thereby suggesting that excessively accumulating life stress not only exerts a negative effect on health, but simultaneously reduces PA uptake in vulnerable populations. Activities where individuals felt singled out, such as fitness testing, present significant barriers to PEPAS. Similarly, an overly competitive, performance-based curriculum acted as a barrier for those who self-identified as 'non-sporty'. Many 16-18-year- olds see current cultural fitness trends as preferable to the range of activities traditionally promoted within PE. It was perceived that previous negative PE experiences acted as a barrier to continued PA into adulthood. A core finding arising from this thesis is the recommendation that promoting lifelong PA habits, particularly in those at risk of elevated life stress, should be a fundamental objective of educators. Furthermore, evidence uncovered during this thesis suggests that PE should be structured around pedagogical models promoting self-efficacy and intrinsic motivation. Also, it is suggested that, during the senior phase, PE should be repackaged into an attractive compulsory brand. Finally, the implementation of current fitness and exercise trends, may prove an effective strategy in promoting lifelong activity and health and wellbeing.