Cycling is increasing in popularity which is accompanied with a higher rate of injuries sustained due to collisions, crashes or falls. A high proportion of these events happen when the bicycle rider loses control of the bicycle. In order to improve bicycle rider control, the skill of riding a bicycle needs to be understood. Therefore, the overall aim of this PhD work was to explore bicycle rider control skills and to examine the effects of different constraints on the control of a bicycle. The first part of this thesis focuses on developing a valid and reliable methodology that can be further used for studying bicycle rider control skill. Firstly, a protocol to determine knee angle during cycling is being developed. Secondly, some technical approaches when studying muscle activity during cycling are being questioned. Lastly, a portable device based on a single angular rate sensor to record steering rate and bicycle roll rate was tested for reliability in an outdoor setup. Second part of the thesis examines the effects on bicycle rider control of three different constraints: 1) expertise, 2) body position and 3) cycle lane design. Results overall showed that all three constraints significantly affect steering and bicycle roll rate.

Rheumatoid Arthritis (RA) is a chronic inflammatory disease that can negatively impact people both psychologically and physically. Health benefits of regular physical activity (PA) have been demonstrated for RA patients (Cooney et al., 2011), however people living with RA are more likely to be sedentary (Sokka et al., 2008; Yu et al., 2015). A Self-Determination Theory (SDT) based approach was adopted in this thesis. The validity and reliability of the Behavioural Regulation in Exercise Questionnaire-2 (BREQ-2) was tested (Chapter 2) within RA patients via a mixed method approach. In a second study (Chapter 3), hypothesised relationships based on SDT between autonomy support from the important other (s), basic psychological needs, motivation regulations and RA patients’ subjective vitality and self-reported PA was tested via structural equation modelling. Presumed mediation effects were also examined. As an incongruence between PA measurement has been found previously (Semanik et al., 2011), the agreement with self-reported PA and sedentary time (ST) were determined (Chapter 4) on both objective and subjective PA, then related to the VO2 max test. The next investigation (Chapter 5) assessed the associations between motivation regulations, objectively measured PA/ST and a key indicator of compromised mental health (i.e., depressive symptoms). Overall findings of this thesis were discussed in Chapter 6, and future research directions, practical implication and limitations proposed.

It is commonly believed that with increased age, movement dexterity becomes slower and increasingly clumsy when performing simple every day tasks. In the General Introduction of this PhD thesis (Chapter 1), literature that supports evidence for this relationship was reviewed. In addition, literature that has attempted to understand co-variance factors that may influence the age and dexterity relationship were also presented. From this, the general thesis hypothesis raised was that other factors such as sense of touch, attention ability or strength might also correlate with age and so possibly could also explain the reduced dexterity variable. Five empirical chapters present the experiments conducted to address the hypothesis, and the data from these are discussed in the General Discussion (Chapter 7). The empirical chapters consisted of three main areas of experimentation. That is, Chapter 2 ran preliminary screening data, Chapters 3 and 4 tested the effects of selective attention ability on the age - dexterity relationship and Chapters 5 and 6 tested the effects of strength on the age - dexterity relationship. In more detail, Chapter 2 used standard clinical measurements to assess the effects of age on fine and gross movement dexterity, sense of touch, selective attention and strength. The data showed that all factors declined with increased age, but that strength and selective attention seemed particular relevant to general upper limb dexterity. In Chapter 3, the impact of selective attention ability was assessed using a modified and motion tracked dexterity task. This demonstrated that the age and dexterity relationship was not generalised across all movements, but instead was specific for phases of action that contained a selective attention component. Chapter 4 followed up these data by showing evidence of impaired selective attention and inhibition with increased age. Chapter 5 sought to clarify the impact that strength had on the age and dexterity relationship. The findings showed that while age and strength were related, age explained more of thedata’s variance for steadiness and movement tracking dexterity, whereas strength explained more of the data’s variance for aiming and tapping dexterity. In Chapter 6, the findings of Chapter 5 were tested by directly manipulating hand grip strength and measuring the resultant effects on tapping dexterity. The data supported Chapter 5 and confirmed that hand grip strength had a clear impact on the age and dexterity relationship. Together, the data presented in the PhD thesis suggest that other factors contribute to the effects of age on dexterity, and support the idea that better management of these confounding factors may allow for a better understanding of the age and dexterity relationship and furthermore, help older adults enjoy better movement dexterity.

In the healthy human the primary driver for neuroplastic change is experience, in the form of learning and memory. Visuomotor learning has been shown as an effective experimental paradigm for inducing neuroplasticity, which is expressed as changes in corticospinal excitability (CSE). The present thesis uses the transcranial magnetic stimulation (TMS) stimulus response (SR) curve to assess learning induced changes in CSE. The first study presents a means of rapidly acquiring the TMS SR curve. Study two compares learning induced modulation of CSE between proximal and distal muscles. Study three assesses the influence of hand preference on learning induced changes in CSE. The results of study one indicate that it is possible to acquire the TMS SR curve in under two minutes. Studies two and three suggest distal muscles have a greater capacity for CSE modulation and this modulation of CSE is invariant to hand preference. Importantly, there is considerable variability in learning induced modulation of CSE. This thesis presents a novel paradigm for rapidly acquiring the TMS SR curve. It also highlights an important point for future studies of learning induced neuroplasticity – there is considerable variability in the neuroplastic response to a single session of visuomotor learning.

Understanding brain health is crucial in diagnosing, preventing and treating neurocognitive conditions (e.g., dementia). However, the literature reveals discrepancies around the interpretation of brain health and differences between populations. This thesis investigates brain health measures from different disciplines, including: resting cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) (using transcranial Doppler (TCD) ultrasound and magnetic resonance imaging (MRI)); cognition (including attention and memory); and quality of life (QoL) questionnaires. Differences between age (younger versus older) and cardiorespiratory fitness (fit versus unfit) groups were also investigated. Importantly, these multimodal brain health measures were completed in the same cohort. Declines were observed between younger and older groups in resting CBF measures (derived using TCD and MRI), and cognitive performance measures (attention-switching, learning and memory). In the older group, higher fitness offset declines in resting CBF and improved markers of cognition. In both groups, fitness significantly positively correlated with better QoL. However, no differences between age or fitness groups were observed in CVR measures. Further, CVR differed significantly depending on the imaging and analysis approach used. Future research is required to elucidate the cause of discrepancies and determine differences between groups (i.e., age/fitness/disease). Further, robust approaches to assess brain vascular health are needed.

Current methods used in the diagnosis of coronary artery disease vary in sensitivity and specificity and have a number of limitations. The aim of this thesis investigation was to explore a new technique for inducing hypocapnia in resting subjects and investigate whether this technique has any clinical applications in the diagnosis of coronary artery disease. In 18 healthy subjects, the effects of hypocapnia, induced by mechanical hyperventilation (in 21% or 15% inspired O\(_2\)), on cardiac electrical activity and heart function were investigated using an electrocardiogram (ECG) and echocardiogram. In addition, a pilot study was conducted to examine the effect of hypocapnia on the ECG of four patients suffering from coronary artery disease with stable angina. Experiments using mechanical hyperventilation showed that the most severe hypocapnia tolerable (PetCO\(_2\) = 20 ± 0mmHg) in normal healthy subjects causes a significant increase in T wave amplitude (increase of up to 0.09 ± 0.02mV, P < 0.01) in the anteroseptal leads (V\({_1-3}\)) of 18 normal subjects but these changes do not exceed the clinical thresholds for hyperacute T wave amplitudes. Hypocapnia did not cause any other significant ECG or echocardiographic changes during mechanical hyperventilation. Reducing inspired O\(_2\) to 15% during hypocapnia in nine normal subjects did not accentuate any of the T wave changes seen during hypocapnia, nor did it cause any clinically significant changes to appear. In two patients suffering from coronary artery disease with stable angina, no clinically significant ECG changes were seen during hypocapnia. These patients were taking isosorbide mononitrate medication which could have interfered with the vasoconstrictive effects of hypocapnia. In two patients not taking this type of medication, small increases in T wave amplitude (of up to 0.05 ± 0.01mV) and decreases in ST segment height (of up to 0.05 ± 0.01mV) were observed. These results show that hypocapnia, induced by mechanical hyperventilation, of the greatest severity tolerable in normal subjects, does not induce clinically significant ECG changes in normal healthy subjects as has been previously suggested. Preliminary results from four patients suffering from stable angina suggest that hypocapnia does cause small ECG changes but these are not consistent and are unlikely to be of clinical importance. However, conclusions about the clinical applications of this technique cannot be made until more patients are studied.

Exercising muscle needs a constant supply of oxygen for the aerobic metabolism of carbohydrate and fat, and regulation of the blood supply to muscle during exercise is therefore critical. Heart rate, stroke volume and minute ventilation all increase during exercise, and sympathetic vasoconstriction diverts blood to exercising muscle. It is well recognised that receptors in skeletal muscle play a vital role in the regulation of blood flow, including receptors sensitive to products of anaerobic metabolism such as lactate and hydrogen ions: metaboreceptors. Activation of the muscle metaboreflex signals the need for an increase in blood flow, and leads to an increase in cardiac output, ventilation and sympathetic vasoconstriction to non-essential organs. Exercise intolerance is one of the most disabling symptoms in patients with a range of cardiorespiratory diseases. Abnormalities of skeletal muscle favouring anaerobic metabolism have been documented in both chronic heart failure and chronic obstructive pulmonary disease (COPD), and this is thought to be relevant to exercise limitation in these diseases. Studies looking at patients with chronic heart failure have demonstrated an increase in muscle metaboreflex activity. It is thought that abnormal skeletal muscle generates greater quantities of anaerobic metabolites, leading to increased metaboreceptor activation. This in turn causes an increased sympathetic nervous system and ventilatory response to exercise. Patients with COPD have been shown to demonstrate similar skeletal muscle abnormalities, so we hypothesised that we would also find an increase in muscle metaboreflex activity in this group. It is possible to quantify muscle metaboreflex activity by exercising a small muscle group to fatigue then isolating it from the rest of the circulation with a sphygmomanometer cuff. This traps the metabolic products of exercise in the muscle and leads to prolonged stimulation of metaboreceptors. This can be measured as a sustained increase in blood pressure and ventilation when compared with control recovery without cuff inflation. The aims of this thesis were as follows: (i) to assess if it is possible to quantify the muscle metaboreflex in a group of patients with COPD and to determine whether muscle metaboreflex activity is increased in patients with more severe disease, (ii) to determine whether supplementation with oral creatine monohydrate alters muscle metaboreflex activity, upper limb strength or endurance and respiratory muscle strength in patients with COPD, (iii) to assess the effects of diabetic autonomic neuropathy on muscle metaboreflex function, and (iv) to evaluate whether pulse transit time is of use in the measurement of muscle metaboreflex activity. In our first study, we looked at a group of patients with stable COPD and found that rhythmic forearm exercise followed by post-exercise forearm ischaemia led to a sustained increase in blood pressure and minute ventilation when compared with control recovery. These findings are in keeping with previously published observations in normal subjects and in patients with chronic heart failure. We found that there was no difference in muscle metaboreflex activity between the groups of patients with moderate or severe disease. We then performed a randomised, double-blind, placebo-controlled, crossover trial looking at the effects of loading a group of patients with stable COPD with creatine monohydrate. We demonstrated a small increase in body weight and an increase in peak inspiratory and expiratory mouth pressures, but there were no effects on muscle metaboreflex activity or forearm muscle strength, endurance or recovery. A group of patients with type I diabetes mellitus was then used to study the effects of autonomic neuropathy on muscle metaboreflex function. We found that there was no difference in metaboreflex activity between subjects with diabetic autonomic neuropathy and subjects with diabetes but no evidence of autonomic neuropathy, suggesting that the afferent and efferent limbs of the muscle metaboreflex were intact. Our final study evaluated whether pulse transit time could be used to assess muscle metaboreflex activity. Pulse transit time is defined as the time taken for a pulse wave to travel between two arterial sites, and can be easily and non-invasively measured. It is thought to reflect blood pressure and arterial tone. In a group of healthy subjects, we found that pulse transit time fell with rhythmic handgrip exercise, and post-exercise muscle ischaemia led to a sustained fall in pulse transit time when compared with control recovery. Pulse transit time therefore shows promise in the measurement of muscle metaboreflex activity, but further studies are required. Studies comparing pulse transit time with more invasive measurements such as muscle sympathetic nerve activity would be of particular interest.

Recent research has highlighted the potential importance of collective efficacy in enhancing understanding of group productivity within both mainstream and sport psychology, The aim of this thesis was, within a sport and physical activity setting, to progress beyond examining the collective efficacy - performance relationship and to focus upon examining the mechanisms through which Bandura (1982,1986,1997) predicts collective efficacy influences performance. Consistent with Bandura's proposals it was predicted that collective efficacy beliefs would influence group activity choice, goal selection, effort allocation, persistence levels, affective (including competitive state anxiety) reactions and team-referent attributions. A further research aim was to examine potential sources of collective efficacy. Thus, the role of team performance experiences and the attributions to these experiences as determinants of collective efficacy beliefs were examined. To achieve these aims five studies, three experimental studies and two field based surveys, were conducted. The experimental studies provided support for the prediction that an individual's collective efficacy beliefs are important determinants of that individual's stated choice of activity for their group, the goals they advocate that their group adopts, and the effort they allocate to the group task. Partial support for Weldon and Weingart's (1993) proposed relationship between collective efficacy and group goal commitment was also observed. However, no support was found for the predicted differences in persistence between individuals high and low in collective efficacy. The second and third of these studies indicated that performance information was an important source of collective efficacy. The field based surveys also provided support for aspects of Bandura's model of collective efficacy. The first of these indicated the existence of a small, negative relationship between an individual's collective efficacy beliefs and the level of cognitive anxiety experienced prior to competition and a moderate, positive relationship between an individual's collective efficacy beliefs and the level of positive affect experienced prior to competition. The second of the survey studies indicated that individuals with high collective efficacy used more controllable attributions than did those with low collective efficacy. Furthermore individuals' collective efficacy beliefs were observed to influence the team-referent attributions made after perceived success and failure of the team's performance. Specifically following perceived poor performances, high collective efficacy individuals used more external and unstable attributions than did those low in collective efficacy, whilst following good performances high collective efficacy individuals used more internal and stable attributions. This study also provided support for the role of controllable team-referent attributions in mediating the influence of performance attainments on collective efficacy beliefs with the use of controllable attributions leading to increases in collective efficacy following success and failure. Overall the research conducted provides support for a number of the mechanisms through which it is proposed that collective efficacy operates on performance, and for the role of performance attainments and team-referent attributions in determining collective efficacy. It also provides further evidence for the importance of collective efficacy to the understanding of group productivity and individuals who constitute groups.

Attempts have been made to account for the increased propensity of upper respiratory tract infections (URTI) in regularly training individuals, by focusing on the effect of exercise on the primary mucosal immunoglobulin secretory immunoglobulin A (sIgA). However, the pathophysiological significance of observed changes in sIgA levels remains unclear, as indeed does the existence of increased URTI in athletes. The aim of this work was to examine the use of sIgA as a marker of exercise-induced immunomodulation and its possible role in protection against URTI. Before these questions could be addressed the optimum method for saliva collection, and the ideal terms for expression of sIgA levels were investigated. Experimental data advocate the use of the passive dribbling method above the use of salivettes. Salivettes were found to result in an underestimation of both saliva flow rate and protein concentrations as a consequence of limited absorption (3 ± 1ml) and variable retention of the sample (49.1 ± 24.9%). Secretory IgA levels are commonly expressed in terms of secretion rate which is the product of saliva flow rate and sIgA concentration. Examination of the relative contribution of these two factors to secretion rate revealed that exercise-induced changes in saliva flow rate (-51 %) matched the changes in secretion rate (-51 %), whereas changes in sIgA concentrations (+4%) did not. It was concluded that changes in saliva flow rates have an important role with the occurrence of symptoms associated with URTI whether induced by infective or inflammatory factors. Epidemiological data from others on the incidence of symptoms associated with URTI in marathon runners have provided evidence on the incidence of URTI in athletes. However here, reported symptoms associated with URTI were most common during the race suggesting that an infective agent was not involved. Examination of the effect of marathon running revealed a non-significant decrease in saliva flow rate (-27.7 ± 15.8%). A final study investigated the effect of increased ambient temperature, and the possibility of fluid replacement as a intervention strategy against exercise-induced decreases in saliva flow rate. This study revealed that exercise reduced saliva flow rate exercise in the heat exacerbated this and that fluid replacement tempered the exercise-induced decrease. Changes in saliva flow rate were found to be associated with changes in plasma volume. The overall conclusions of this thesis are that innate defence mechanisms such as saliva have a role to play in conferring defence against potential pathogens, and therefore warrant further investigation. It appears from data presented in this thesis that saliva flow rate is affected by exercise, perhaps to a greater extent than sIgA concentration. Changes in saliva flow rate with exercise may have a role to play in the purported increased incidence of URTI reported by athletes, and fluid replacement may provide an effective strategy against this exercise-induced decrease.

There is a lack of scientific research into roller hockey. The aim of this thesis was to analyse the muscular demands of roller hockey match play, using four techniques. These were a) Match analysis: Two Premier League roller hockey matches were recorded using two stationary video cameras. Manual, field-by-field analysis established all the actions performed by players in a match situation, the percentage of match time spent performing each action, their frequency and the mean duration of each action. Also recorded was the direction travelled, while the intensity of each action was subjectively assessed. b) Heart rate analysis (n=5): heart rate was recorded every 5 s during training and competition. Heart rate and performance were also measured during a maximal progressive 20-m shuttle skate test and oxygen consumption (V02) was calculated. c) Kinesiology analysis (n=l): Two-dimensional video analysis was used to establish the phases, joint actions, and muscular activity of each roller hockey action. d) Telemetric surface electromyography (EMG) analysis (n=6): activity was monitored in 8 muscles during training practice and training matches. The results of the match analysis showed 71% of match play was spent rolling, and 70% was spent travelling forwards; 22% was conducted at high intensity. Minor differences were found in match play activity between forwards and defenders, and between winners and losers. Comparisons between activity in the 1st and 2nd halves showed significantly more sprinting in the 1st half (p<0.05) and significantly more rolling and low intensity activity in the 2nd half (p<0.05). Mean heart rates during competitive matches (176 beats/min) were significantly higher (p<0.05) than during training matches (166 beats/min). The maximal 20-m shuttle skate test produced a mean predicted V02max, of 54 ml/kg/min, and maximal heart rates similar to competitive matches. The kinesiology analysis established 8 muscles central in roller hockey; these muscles were monitored in the EMG analysis. Electromyography revealed that performance of roller hockey actions during training produced the greatest EMG activity in the pectoralis major, while sprinting and forehand slap shots were the most demanding actions. Combining the results of the electromyography analysis with the match analysis revealed the high physical demands of shooting and the skating actions of pushing and sprinting. This thesis constituted the first long-term study of roller hockey, and it provided evidence that may be used in developing technique and improving sport specific fitness.