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No description available.

Exercise training is known to increase endothelial function and provoke arterial remodelling both locally and systemically. This thesis was designed to further examine these relationships by investigating the acute response to different exercise intensities, with and without shear rate modification. Shear rate modification was also used to examine the impact of systemic exercise training on brachial haemodynamics. Finally, the effect of inactivity on vascular function and arterial remodelling were studied using novel models of inactivity. The aim of Study 1 was to examine the effect of shear stress on upper limb brachial artery dilation during acute cycle exercise of different intensities. The impact of three randomised bouts of 30 mins leg cycling (50, 70 and 85% HRmax) on brachial artery blood flow, shear rate (SR) and brachial diameter, was measured bilaterally and simultaneously. SR was further manipulated in one arm via forearm heating (40±1°C) in a water bath (+0C) throughout the exercise bouts. Exercise induced stepwise increases in SR in the unheated arm (~0C) (P<0.05). In the +o( arm, SR was significantly greater than in the ~o( limb. Brachial artery diameter increased post- exercise in ~o( by 3% (50%HRmax; P>0.05 vs. baseline), 7% (70%HRmax; P<0.05) and 9% (85%HRmax; P<0.05). In the+°C arm, post-exercise brachial diameter increased at all exercise intensities (P<0.05) and was significantly greater (P<0.05) than in the ~°C limb at 50% (12%), 70%HRmax (14%) and 85%HRmax (15%). In conclusion, increases in shear rate during incremental lower limb exercise are associated with increases in brachial artery diameter. This response is exaggerated with larger SR induced by localised heating, indicating that leg exercise has systemic effects on arterial diameter and that SR is an important stimulus to vasodilation during exercise in humans. The second study examined brachial artery flow mediated dilation (FMD) (using high resolution echo-Doppler) pre, and post (0, 1, 2, 24hr) 3 bouts of acute 30 min exercise at different (50, 70 and 85% HRmaxl intensities. Shear rate area-under-the- curve (from cuff deflation to peak dilatation; SRAUcl was calculated as the eliciting stimulus for FMD. Both baseline diameter and SRAUC were elevated by exercise. With covariate-control of these variables, the change in brachial artery FMD was negligible after exercise (~5 minutes post exercise) at 50% HRmax (6.3±2.6 vs. 5.9±2.5%; 95%(1 for difference: -0.59 to 1.34%) whilst a larger changes in FMD were noted after the exercise bouts at 70% (6.1±1.8 vs. 4.7±1.9%; 95%(1 for difference: 0.08 to 2.58%) and at 85% HRmax (6.6±1.6 vs. 3.6±2.2%; 95%(1: 0.41 to 5.42%). A further 2-way ANOVA revealed there were no changes in FMD at any other time- point post exercise (1, 2, 24hrs) and FMD normalised by Ihr post. These data indicate, for the first time, a 'dose-response' relationship between exercise intensity and the reduction in FMD, even when exercise-mediated changes in shear and baseline diameter are accounted for. The purpose of Study 3 was to examine the contribution of shear stress to changes in vascular function in the non-exercising upper limbs in response to lower limb (systemic) cycling exercise training. Subjects participated in an 8-week cycle training study undertaken at 80% HRmax, with unilateral cuff inflation around the forearm during each exercise bout. FMD, partly NO-mediated endothelial function (i.e. ischaemic handgrip exercise (iEX)), and endothelium-independent dilation to a NO donor (i.e. glyceryl trinitrate (GTN)) were measured at 2, 4 and 8 weeks. Cycle training increased FMD in the non-cuffed limb at week 2 after which, responses returned towards baseline levels (5.8±4.1, 8.6±3.8, 7.4±3.5, 6.0±2.3 at 0, 2, 4 and 8 weeks, respectively; ANOVA: P=0.04). No changes in FMD were observed in the cuffed arm. In addition, no changes were evident in response to iEX or GTN in either the cuffed or non-cuffed arms (P>O.05) across the 8 week intervention period. These data suggest that lower limb cycle training induces a transient increase in upper limb vascular function in healthy young humans which is, at least partly, mediated via shear stress. Exercise training is associated with rapid changes in endothelial function, which occur within days of starting training. Whilst long-term physical inactivity has a strong effect on vascular structure, little is known about the immediate impact of inactivity on vascular function. Therefore, Study 4 measured changes in vascular function before, during (day 4) and after 8 days of unilateral forearm inactivity induced by wearing a sling on the non-dominant arm. Maximal handgrip strength of the inactive forearm decreased after 8 days, confirming physical deconditioning. There were no significant changes in brachial artery baseline diameter, FMD, iEX or GTN across the 8 days in either arm (P>0.05). A significant decrease in peak blood flow was found in the intervention arm (2-way interaction: P=0.03) that is suggestive of remodelling of forearm resistance vessels. However, measures of (largely and partly) NO-mediated endothelial conduit artery function were not altered across an 8 day period of inactivity. Whilst increases in mean arterial shear stress are known to induce improvements in arterial function and remodelling in humans, animal data have demonstrated that retrograde shear is associated with pro-atherogenic effects. However, relatively little is known regarding the effect of retrograde shear rate on vascular function in humans in vivo. In order to provoke retrograde shear, subjects wore a compression sleeve on one forearm for 8 clays. Measurements were taken before and during acute (lhr) exposure to a compression sleeve on baseline day O. Measurements were taken after 4 and 8 days exposure to the compression sleeve. There were no significant changes in mean or antegrade shear rate during exposure to the compression sleeve. However, the compression sleeve resulted in an immediate increase in retrograde shear rate in 6 subjects (P<O.05, intervention-group), but remained near resting levels in the other 6 subjects (P>O.05, control-group)i.e. subjects in whom the compression sleeve did not increase retrograde shear were the control group. The intervention group demonstrated a significant decrease in FMD after 1 h compression sleeve (P<O.05), but not in the control group (P>O.05). After 8-days using the compression sleeve, no significant changes in FMD, iEX, or GTN-response in the intervention and control group (all P>O.05) were observed. In conclusion, short-term increases in retrograde shear rate decrease FMD, but not chronically. Data in this thesis provide evidence for the role of blood flow and shear stress, as a result of exercise and inactivity, and its immediate effects upon the vasculature.

The periodic alternation of light and darkness over the solar day has a fundamental role in synchronising human circadian rhythms. Artificial light is known to alter circadian timing depending on time of administration; early morning light can advance circadian timing while late evening light can delay circadian rhythms. Nevertheless, there is a lack of research on how manipulations of the body clock, via bright light, can enhance human performance and/or alleviate the effects of jet-lag after transmeridian travel. The doctoral programme communicated in the present thesis was designed to fill some of these gaps in knowledge. In the first experiment, the acute effects of light exposure on thermoregulation, pineal function and autonomic nervous system function (indicated by the rate pressure product) were examined. At 20:00 h, eight healthy men were exposed to a baseline period of dim light « 12 lux) for 45 min followed by 0 lux for another 60 min. Thereafter, participants were exposed to either polychromatic bright light with blue photons (2500 lux), blue photons removed (2,500 lux) or 0 lux for 30 min. Baseline data was altered for all variables in the two light conditions, suggesting an "expectancy effect". There was evidence that light attenuated the nocturnal fall in core body temperature and rise in melatonin. These data highlight that the circadian system and other areas of the brain which are stimulated by light are still sensitive to short duration exposure and these effects are amplified by the inclusion of blue spectrum light. In a follow-up study, the effects of light exposure (blue photons included polychromatic bright light vs. no light) on subsequent early morning performance were examined under conditions of thermal stress. Participants were woken at 06:30 h. At 07:00, participants entered an environmental chamber set at 35°C and 60% relative humidity. Three 10-min bouts of exercise (55% V02max) were completed on a cycle ergometer with each bout separated with 10 min of passive recovery. Participants then completed a 10-km cycling time-trial. Core body temperature was measured every 30 s throughout the experiment using intestinal thermistors. The time of the sleep-trough in core temperature occurred approximately 1.75 h later following bright light (L) vs. no light (NL) (p = 0.07). Just prior to the time-trial, Tc was 0.27 ± OA2°C lower in L than NL (p = 0.07). The time trial was completed 1.43 ± 0.63 min quicker in L vs. NL (p = 0.001). Immediately after the time trial, intestinal temperature was 38.21 ± 0.56°C in BL compared to 38.64 ± 0.42"C in NL (p = 0.10). These data provide the first evidence that a 3D-min exposure to bright light prior to sleep can delay circadian timing to the extent that exercise performance is improved in hot conditions during the subsequent early morning. In the third study, the effects of a simulated dawn during the last 30 minutes of sleep on the subsequent dissipation of sleep inertia were examined and it was questioned whether subsequent improvements in simulated work and physical performance were mediated. Eight participants, who reported difficulty with morning waking, were administered in a random order to a control (C) and a dawn Simulation (OS) trial (starting 30 minutes prior to waking). Subjective ratings of sleep quality and alertness were obtained alongside measures of cognitive performance (addition and a reaction time tasks measured at 5, 30 and 75 minutes after waking at habitual workday times). Physical performance was also measured 35 minutes after waking using a self-paced cycling protocol. After waking in the OS condition, perceived sleep quality was 1.16 ± 0.89 (p = 0.01) points higher compared with C. Ratings of alertness were significantly higher in OS than C throughout.

No description available.

No description available.

Shift-work is increasingly common in society and is associated with a number of health inequalities. The health effects of shift-work can include a redudion in quality and quantity of sleep, insomnia, chronic fatigue, anxiety and depreSSion,decreased vigilance, metabolic syndrome, adverse cardiovascular (especially blood pressure), gastrOintestinal effects and reproductive effects in women. Shift-work is also associated with disturbances to a workers domestic and social life. Physical activity is known to either prevent or alleviate these health inequalities in those with 'normal diurnal' lifestyles such as day-workers. However, shift-work generally decreases opportunities for physical adivity. Moreover, the favourable affects of physical activity on such health inequalities have not been confirmed in shift-workers. The studies in the present thesis are designed to examine the associations between shift-work and physical activity covering a wide range of physiological and psycho-social variables in shift-workers. The first descriptive study was designed to provide the first detailed and multi-researchstrategy examination of LTPA and its correlates in shift-workers. One hundred and sixty one shift-workers partiCipated in the initial cross-sectional study. A cohort of ten of these partiCipants also volunteered for further diary- and inteNiew-based studies. PartiCipants completed the SSI together with a LTPA questionnaire. Gender, job type, age and shift-work experience were explored as correlates of LTPA. The cohort also completed a 7-day diary and wore an accelerometer for assessment of activity counts during work, leisure, and bedtime when working each shift-type (days, nights and rest). Participants also completed a semi-strudured email-administered interview. The total energy expenditure per week in LTPA of male shift-workers was found to be twice that of women. Midwives recorded the lowest LTPA. Firefighters reported the most LTPA. The time spent out of bed during night shift days was 4-h higher compared with rest days. Data from this study indicated that LTPA is generally low amongst shift-workers, the majority of whom are overweight or obese. Jobtype and gender are much more influential on LTPA than age or experience. Shift-workers spend more of their time on rest days in bed. The second descriptive study was designed to explore the relationships between coping strategies adopted by shift-workers and their leisure-time energy expenditure. The importance of coping strategies has been highlighted in previous research. Ninety-five participants completed an adapted version of the completed the SSI together with a LTPA qUestionnaire. Predictors of age, time spent in shift-work, gender, marital status and the various shift-work coping indices were explored with step-wise multiple regression. Leisuretime energy expenditure over a 14-day period was entered as the outcome variable. Gender (p < 0.023) and time spent in shift-work (p < 0.051) were found to be predictors of energy expenditure, with the most experienced, male shift-workers expending the most energy during leisure-time. Overall 'disengagement' coping scores from the SSI were positively related to leisure-time energy expenditure (p < 0.054). In males, disengagement of sleep problems (p > 0.086) was found to be negatively correlated to energy expenditure, whereas disengagement of domestic-related problems was found to be positively related to energy expenditure (p < 0.001). These relations were not found in female shift-workers (p > 0.762). These data indicated that experienced male shift-workers participate in the most leisure-time physical activity. These people 'disengage' more from their domestic-related problems, but less from their sleep-related problems. The next laboratory-based study was designed to examine the acute effects of evening exercise and meal frequency on psychophysiological and performance-related variables during a subsequent period of simulated night-work. Nine healthy participants, completed at least two crossover trials beginning at 18:00 h. Between 19:00-20:00 h, participants either rested or exercised at 50%V02peak and then remained awake throughout the night, completing various tasks until 05:15 h. Six participants completed a total of four trials in which they exercised or rested while either one standardized (SOkJlkg) meal at 22:00 h or two smaller (30 kJ/kg) meals at 22:00 and 02:00 h were eaten. Core Body Temperature (Tc), wrist activity, mood, sleepiness, arousal, self-chosen work-rate, and reaction time were all measured throughout the simulated night-shift. Following exercise, Tcwas Significantly lower throughout the night-shift compared with no prior exercise (95% Cl = 0.00 to 1.01°C), even though wrist activity was higher and sleepiness was lower after exercise. Self-chosen workrate was significantly higher (95% Cl = 20 to 43 W) and reaction time faster during the nightshift that followed exercise. Reaction time and alertness were worst when only 1 meal was ingested during the night-shift (p <0.04). These data indicate that a single bout of evening exercise can improve sleepiness as well as mental and physical performance during a subsequent simulated night-shift ... The findings from the studies in this thesis indicate that many of the short-term health benefits of exercise are apparent in contexts of shift- and night -work. The relatively small final intervention study demonstrates the potential utility of an individualised lifestyle intervention based on motivational interviewing for shift-workers.

Greenhouse gas (GHG) emissions from waste and transportation are of environmental concern. Globally, every year, waste contributes an estimated 5% and transport approximately 23% of the total anthropogenic GHG emissions. Sport contributes to GHG emissions by spectators and participants travelling to/from sporting venues and generating waste. Whilst a small reduction in an individual’s travel and waste may be perceived as having negligible impact, if these are aggregated over a population, the resultant GHG emissions can be significant. Although there is scientific evidence of the environmental impact of major sporting events there is limited research on it at the grassroots level. In addition watching and participating in sport results in wellbeing benefits such as improved self-esteem and mood. This research quantitatively examined both the environmental impacts and wellbeing benefits of sport at the grassroots level focusing on both spectator-dominated and participant-dominated sports in England. Three studies were conducted examining spectator-dominated sport: 1) GHG emissions relating to travel to and from football games; 2) GHG emissions relating to waste at football games and 3) the effects of watching football on mental wellbeing. Two further studies were also conducted assessing participant-dominated sport: 4) GHG emissions from travel to and from running location; and the effects of sport (running) on mental wellbeing and connection with nature and 5) the effects of running outdoors on mental wellbeing (pre and post study). The research showed that both spectators and participants’ sport considerably generated GHG emissions from travel and waste when extrapolated nationally. However, engaging in spectator-dominated or participant-dominated sports resulted in wellbeing benefits. Watching football resulted in better mental wellbeing, while running particularly outdoors resulted in improvements in wellbeing such as improved mood and increase in self-esteem after participating in sport. This research suggests that participating in sport can initiate a positive change in a person’s relationship with the natural world. These findings on the environmental impact and wellbeing benefits of both spectator-dominated and participant-dominated sports have implications for individuals, private sectors, sporting organisations, policy makers and government authorities.

Background and Aims: Regular physical activities have shown to have various health benefits however there is always an accompanying risk of developing musculoskeletal soft tissue injuries. Indeed, damaged tendons account for 30-50% of sports-related injuries where the lifetime risk of Achilles tendon pathology (ATP) approaches 50% in runners, and that of patellar tendon pathology (PTP) is 21% in football players. The exact aetiology and mechanisms of tendon pathologies are still under investigation, however extrinsic and intrinsic risk factors (of which genetic) have been identified. Recent genetic association studies found that gene variants within the TNC, COL5A1, MMP3, GDF5 and CASP8 were associated with ATP in a Caucasian Australian and South African population. Furthermore, epigenetic mechanisms such as DNA methylation and microRNA (miRNA) activity have been implicated in a range of diseases but were never investigated for their role in human tendinopathy. Based on the aforementioned information, this thesis aimed at investigating novel candidate genes that may be associated with ATP and to replicate previously conducted studies in a newly recruited case-control population. Additionally, this thesis aimed at investigating potential differences in DNA methylation profiles and miRNA expression levels between healthy and damaged Achilles and patellar tendons. One hundred and thirty six UK Caucasian participants with clinically diagnosed ATP and 131 asymptomatic, unrelated, physically active control participants were recruited for this study. Furthermore, the previously recruited 173 clinically diagnosed ATP participants and 238 asymptomatic, unrelated, physically active control participants from Australia and South Africa (AUS+SA) were also included in the studies of this thesis. Participants within the combined AUS+SA were genotyped for the ELN rs2071307, FBN2 rs331079, ADAM12 rs3740199, ADAMTS2 rs1054480, ADAMTS5 rs226794, ADAMTS14 rs4747096, and TIMP2 rs4789932 variants, and the UK participants were genotyped for the COL5A1 rs71746744, FBN2 rs331079, GDF5 rs143833, MMP3 rs679620, TIMP2 rs4789932 variants using fluorescent based TaqMan® technology. Furthermore, the UK cohort was genotyped for the COL5A1 rs12722 variant using polyacrylamide gel electrophoresis. Moreover, 10 healthy and 10 diseased patellar tendon tissue samples in addition to 4 healthy, and 1 diseased Achilles tendon samples were obtained for the epigenetic studies. The DNA methylation profile within the TIMP2 and GDF5 promoter regions were analysed for all samples using pyrosequencing technology. Furthermore, the expression levels of TIMP2, miR-21, miR-155, and miR-191 were determined by RT-PCR using TaqMan technology. Results and Discussion: The genetic association studies conducted showed that the FBN2 rs331079 GG genotype was over-represented among the tendinopathy (TEN) group and that the ELN rs2071307 AA genotype was over-represented in the rupture (RUP) group within the AUS+SA population. Furthermore, the COL5A1 rs12722 and rs71746744 were associated with RUP (TT genotype over-represented in the RUP group, p=0.004; OR=4.2; 95% CI 1.58-11.97) and ATP (DEL allele over-represented in the CON group, p=0.046; OR=1.61; 95% CI 1.01-2.56) respectively in the male UK cohort. The GDF5 rs143833, on the other hand, was not associated with ATP (p=0.538) and showed no sign of gender-specific association (female p=0.737; male p=0.319) in the UK population. Furthermore, the CT genotype for the TIMP2 rs4789932 variant was over-represented (p=0.004; OR=1.77; 95% CI 1.20 - 2.64) in the ATP group of the combined AUS+SA population and the CC genotype was over represented (p=0.016; OR=2.36; 95% CI 1.16 – 5.81) in ATP of the UK male cohort. It was also reported that the MMP3 rs679620 GG genotype was over represented (p=0.027; OR=2.51; 95% CI 1.11 – 5.64) in the UK RUP group. The ADAM12 rs3740199 (p=0.633), ADAMTS2 rs1054480 (p=0.316), ADAMTS5 rs226794 (p=0.342), and ADAMTS14 rs4747096 (p=0.849) gene variants were not associated with ATP in the AUS+SA population. Interestingly, individuals carrying the ADAMTS14 rs4747096 GG genotype within the AUS+SA population and the ELN rs2071307 AA genotype within the AUS population developed their injuries at a significantly (p=0.024; p=0.005, respectively) later stage than other participants. Moreover, UK males diagnosed with tendinosis and carrying the GG genotype at the MMP3 rs679620 locus developed significantly (p=0.003) thicker tendons than other participants with the AA, and AG genotypes. The preliminary epigenetic DNA methylation studies showed no differences in the average methylation profiles of the investigated regions within the TIMP2 (p=0.885) and GDF5 (p=0.333) genes in the patellar tendon samples. Moreover, no DNA methylation differences (p=0.617) were observed in the investigated region of the TIMP2 gene in the Achilles tendon samples. Interestingly, the single ATP sample showed a lower GDF5 average methylation profile than the CON samples. Furthermore, the expression of TIMP2 was up-regulated, and miR-191 was down-regulated in the ATP tissue sample compared to the CON group. The expression levels of miR-21 and miR-151, however, were not different between the two groups. Conclusion: This thesis provides evidence that novel genes coding for structural and ECM regulatory enzymes are associated with ATPs in Caucasians. The findings of this thesis should to be replicated in new and larger cohorts from different ethnic backgrounds before being incorporated into multifactorial risk assessment models aiming at reducing the incidence of human tendinopathy.

The aim of this research study was to explore physiotherapy clinicians’ perceptions of both traditional and accelerated pre-registration physiotherapy training courses with regard to professional practice. The term ‘accelerated courses’ refers to shortened study routes that have no significant loss of content. Applicants to pre-registration accelerated courses in physiotherapy require an existing Honours’ degree to incorporate their prior learning and abilities. A mixed methodology approach was used in three phases. Clinical marks of pre registration physiotherapy students from both courses were compared. Results indicated that those from accelerated courses gained higher marks than their traditional counterparts. Interview data from a purposive sample of fourteen senior clinicians was analysed using Interpretative Phenomenological Analysis. Findings were compared with questionnaire results from a larger purposive sample of fifty-one clinicians having gained a 50% response rate Analysis indicated that these clinicians valued physiotherapists trained from both routes but for different reasons. Two major superordinate themes arose. Within ‘Perceptions of Success’ many clinicians noted the accelerated graduates’ greater confidence. This was associated with their extended academic background and/or additional life skills. Many accelerated graduates were said to ‘hit the ground running’ as they quickly acclimatised into the complex working environment. However in the second superordinate theme entitled ‘A Note of Caution’ over-confidence was noted amongst some accelerated graduates. This caused minor difficulties in team dynamics and/or certain aspects of clinical care. Some needed ‘reining in’ in the early stages of their career. In direct contrast some traditional graduates appeared less confident, passive and lacking initiative. Nonetheless these same clinicians preferred this as they saw opportunities to ‘mould’, influence and develop the traditionally trained graduates as they saw fit. Both perceptions are of interest in light of Quality Assurance Agency expectations of Honours and Masters level outcomes and have implications for training and clinical practice alike.