• The acute effect of commonly used preparation strategies on short term high intensity motor capabilities

      Fletcher, Iain M. (University of BedfordshireUniversity of Bedfordshire, 2011-07)
      The overall aim of this thesis was to investigate modalities used as components of pre event/training preparation, to try to develop an optimal preparation strategy for sports performers. It concentrates on the stretch modalities commonly used by athletes as part of a warm-up designed to prepare them for subsequent performance. Past literature suggests that static stretching as part of a warm-up leads to a decrease in performance when compared to an active warm-up or a warm-up including dynamic stretches. Not surprisingly this has led to a movement away from static to dynamic stretches by many athletes. The presented publications were conducted to clarify a number of issues raised by past research studies. A lack of ecologically valid studies is apparent; the static stretch protocols used in most of the early research in this area has failed to explore what sports performers actually use as part of their training, while there was a lack of research examining the effect of dynamic stretches on performance. Of particular relevance is the lack of research looking at the mechanisms behind the changes in performance linked to warm-ups incorporating dynamic stretches. Therefore, this group of publications attempts to systematically examine the effects on performance of manipulating the stretch component of an active warm-up, while exploring the potential mechanisms linked to any changes in performance. The general findings of this series of papers provides evidence that static stretches, as part of an active warm-up, are linked to a decrease in the acute performance of a range of physical capabilities; including sprint, agility, jump and maximal force output. The mechanisms behind these performance changes are multifaceted, with decreases in core temperature and heart rate, decreases in musculotendinous unit stiffness and a decrease in muscular activity, when compared to a general active warm-up established. In contrast when a dynamic stretch replaces the static stretch component and is incorporated within a warm-up, performance is enhanced when compared to an active warm-up. The mechanisms behind this seem to be less temperature related and more closely linked to the neuro-muscular system. Greater muscular activity is linked to dynamic stretches, causing an increase in peak force and rate of force development, compared to an active warm-up protocol. This effect seems to be enhanced the faster and more specific the dynamic stretches are to the chosen performance measure, while combining static stretches with dynamic stretches as part of a preparation strategy still leads to decreases in performance compared to an active warm-up combined with dynamic stretches. In conclusion, to maximise acute maximal performance in sports specific motor skills, an active warm-up combined with specific dynamic stretches is recommended to sports performers and coaches.
    • The boxer’s point of view: an ethnography of cultural production and athletic development among amateur and professional boxers in England

      Stewart, Alex (University of BedfordshireUniversity of Bedfordshire, 2008-08)
      Since the late nineteenth century boxing in England has been socially organised into two ideologically distinctive versions - amateur and professional boxing – that to this day are practiced in spatially segregated social universes. Nonetheless, both amateur and professional boxing-practitioners understandings and lived experiences in and through boxing are necessarily grounded in the wider social and cultural contexts through which they interpret meaning and construct worldviews and identity. Thus despite the institutional, ideological and spatial boundaries demarcating either code, on a rather more subtle yet incredibly powerful cultural level, amateur and professional boxing are both symbolically and practically deeply intertwined. Over a five year period, I conducted ‘insider’ ethnographic research among distinct cohorts of amateur and professional boxers based in Luton and London to investigate the lived experiences and socially constructed worldviews, values and identities developed by practitioners immersed in either code. The overriding aim of this research was to critically evaluate the limits and possibilities of boxing-practitioners association with and development through ‘boxing’ henceforth. The findings of this ethnography reveal that it was common for the amateur and professional boxing-practitioners studied to cultivate empowering identities through intersubjective and socially validating instances of purposefulness, expressivity, creativity, fellowship and aspiration. These lived dimensions were grounded in sensuous, symbolic and emotional attachments respective to the social organization defining the social practice of either code of boxing. Equally, the research reveals that under the veneer of collective passion for and consequent fellowship experienced through boxing, an undercurrent yet ever-present sense of dubiety, tension and intra-personal conflict was in evidence among both the amateur and professional boxing-practitioners studied. It is suggested, therefore, that as a consequence of an array of both micro and macro post-industrial societal reconfigurations defining the structural principles of amateurism and professionalism in the practice of ‘boxing’, contemporary boxers are increasingly predisposed to developing athletic identities predisposed towards patterns of meaning production “…dominated by market-mediated consumer choice and the power of individualism” (Jarvie 2006 p. 327). Thus through complex, historically dynamic and seemingly paradoxical social processes of cultural (re)production and transformation - dialectically fusing individualistic aspirations geared towards self-interested gain, acts of group and subcultural fellowship and social resistance to measures of institutionalised control - it is argued that the role of boxing as an agent for humanistic personal and social development in the contemporary late-modern era of structural reconfiguration is progressively rendered impotent.
    • Can exercise ameliorate the symptoms of Parkinson’s disease? modes and mechanisms

      Ali, Hossam Eldin Hamdy Ahmed (University of BedfordshireUniversity of Bedfordshire, 2012)
      Movement disorders are the hallmark of Parkinson’s disease (PD) and can severely compromise an individual’s ability to perform well-learned motor skills such as walking, writing, turning around and transferring in and out of bed. The first symptoms of PD typically do not appear until a critical threshold of 70-80% loss of the striatal neurotransmitter called Dopamine (DA) is exceeded. The loss of DA compromises the connection between the striatum and the Substania Nigra (SN); this connection is essential for the control of body movement. The lifelong management of individuals with PD needs a multidisciplinary approach, which includes coordination of pharmacological and non-pharmacological interventions. The use of prescribed exercise as a non-invasive PD symptom management tool is well recognized. What needs further research and development is an evidence-base for the type, frequency, intensity, duration etc. of exercise bouts. It is however ethically, socially and morally challenging to put unknown physical demands on PD sufferers, therefore in vivo and in vitro studies will be essential in delineating and targeting appropriate interventions. Additionally, in order to establish whether the various interventions are effective will also require a simple measure, preferably one that can be detected following exercise. Ca2+ plays an important role in the synthesis of DA via the Ca2+ calmodulin system and its increase in exercise coincidences with the reported positive effects of exercise on dopamenirgic neuron activity. The aim of this thesis was therefore to use in vivo, in vitro and human methodologies to establish a role for physical exercise in the amelioration of the symptoms of PD. The in vivo study comprised of four groups of experimental animals (rats): a control group (C), a training exercise group (E), a group in which Parkinson’s was induced via systemic injections of PD toxin MPTP (PD) and a group where PD-induced animals were trained/exercised (PDE). (E) and (PDE) groups were trained with 8 weeks of endurance exercise at 90% of the lactate threshold (LT), 5 times a week with each bout lasting for 45 min using a custom-built rodent treadmill. After 8 weeks, all animals were sacrificed and brain samples were collected for immunohistochemistry and western blot analysis. Ca2+ calmodulin kinases I (CaMK-1) and IV (CaMK-4) were investigated as indicators of the activity of the Ca2+ calmodulin pathway. Immunohistochemical analysis of SN region indicated that in the PD group, CaMK-1 and CaMK-4 expression was suppressed when compared with control (C) animals. This phenotype was apparently rescued by endurance exercise as those animals. The western blot results also showed quantitative differences in CaMK-1 and CaMK-4 proteins in the studied brain regions in the (PDE) and (E) groups compared with the PD group. It was concluded from this data that endurance exercise could up regulate the expression of both CaMK-1 and CaMK-4 in the brain of PD sufferers. It was postulated that changes in Ca2+ levels might therefore drive the neuroprotective effect of exercise. The in vitro study was designed to test the hypothesis generated from the in vivo work that Ca2+ is a main effector of the neuroprotective effect of exercise. The SH-SY5Y human neuroblastoma cell line is used as a model of DA neurons as it has DA activity and can synthesize DA. PD was simulated in these cells by exposure to the toxin 6-OHDA whilst addition of Ca2+ was used as an “exercise mimic”. Results showed differences in the survival of SH-SY5Y cells after exposure to specific concentration of Ca2+ following treatment with 6-OHDA. Finally, in order to assess the importance of this data to the clinical population and to further develop the concept that Ca2+ is a major effector of the positive effect of exercise, the effect of moderate-level exercise on the levels of blood Ca2+ in subjects with PD was investigated. Measures of cardiovascular physiology and blood biochemistry (total blood Ca2+) were obtained during cycling exercise at an intensity of 90% of the lactate threshold. Results indicated exercise to be beneficial in alleviating motor symptoms of PD.
    • Determinants, measurement and promotion of physical activity in 10-14 year-old Bedfordshire children: a multidisciplinary approach

      Denton, Sarah J. (University of BedfordshireUniversity of Bedfordshire, 2011)
      Regular moderate-vigorous physical activity (MVPA) is associated with significant physiological and psychological health benefits (Department of Health, DoH, 2004). However, many children are not undertaking recommended levels of physical activity (PA) (DoH, 2009). This research examined relationships between physiological health parameters, psychological determinants and PA levels in 10-14 year old schoolchildren (N = 249) and assessed the influence of three school-based PA interventions on these constructs in the context of the Health And Physical activity Promotion in Youth (HAPPY) study. Study 1 revealed that sedentary behaviours, moderate PA (MPA), vigorous PA (VPA) and MVPA levels were higher on weekdays than weekend days (p < .001). However, schoolchildren’s PA is often difficult to measure accurately. The self-report measure utilised in study 2 underestimated total MVPA versus accelerometry for both sexes on weekdays and girls on weekend days (p < .01). However, study 3 highlighted a lack of agreement between two RT3® triaxial accelerometer cut-offs for all activity categories. The importance of VPA for promoting health was highlighted in the updated PA guidelines (DoH, 2011). Study 4 reported that cardiorespiratory fitness (CRF) was positively associated with VPA but not MPA (β = .27, p < .01) and inversely correlated with measures of body composition (% body fat; body mass index; waist circumference) (r = -.74, r = -.60, r = -.39, p < .001). Knowing the health benefits of regular MVPA and VPA, it is important to understand the determinants of PA intentions and behaviours to more effectively promote PA in less active children (studies 5 and 6). An exploratory analysis of the constructs in the Revised Theory of Planned Behaviour and the Modified Social Learning Theory for children predicted PA intentions (R2 = .38, F(5, 171) = 20.19, p < .001; R2 = .13, F(6, 147) = 3.4, p < .01, respectively) but the constructs in either model were unable to predict PA. Recognising the need to promote PA levels, study 7 investigated the effectiveness of three school-based interventions (vs. control) on outcome variables included in studies 1, and 4-6. The Health Education and Psychology Health Promotion conditions produced significant positive change scores between data collection 2 and 3 for CRF (vs. control) whereas the Youth-Led condition produced significant change scores between baseline and data collection 2 for generalised self-efficacy (vs. control). No significant change scores were reported for PA, the RTPB constructs or intentions. In conclusion, this research has emphasised the importance of employing a multidisciplinary approach to aid understanding of schoolchildren’s PA levels. Specific highlights include low weekend day PA as a possible future PA promotion target, although it is vital that accelerometry cut-points are standardised, and the relevance of VPA and body composition in predicting CRF. The psychological models identified some important determinants of PA intentions, but a prominent intention-behaviour gap and a need for more intensive interventions to promote PA levels was apparent.
    • Dietary glycaemic carbohydrate, physical activity and cardiometabolic health in postpubertal adolescents

      Davies, Ben Rhys (University of BedfordshireUniversity of Bedfordshire, 2013-08)
      The principle aims of this work were two fold; firstly to identify the current dietary intakes (specifically dietary glycaemic carbohydrate (CHO)) and physical activity (PA) and cardiorespiratory fitness (CRF) levels of a UK, postpubertal, adolescent population (n = 105) and assess the relationship between these factors, adiposity and cardiometabolic health. Diet and health relationships were assessed whilst accounting for energy misreporting and controlling for levels of PA and CRF. The effect of excluding dietary misreporters on the associations between glycaemic CHO and health was assessed whilst comparing an established technique (the Goldberg equation) to a novel approach (the ratio of energy intake (EI) to energy expenditure (EE)), which utilised RT3 accelerometry data (EI:EE(RT3)). Associations of PA and metabolic risk factors were also assessed whilst comparing two child specific PA thresholds for the assessment of PA subcomponents. Secondly, the impact of a flexible, ad libitum, low GI dietary intervention on cardiometabolic health was examined in an „at risk‟, overweight, postpubertal, adolescent population. Glycaemic index (GI) but not glycaemic load (GL) was shown to be associated significantly with anthropometric measures (body mass index (BMI), waist circumference (WC)) and adiposity (body fat percentage (BF%)) in this general group of post-pubertal adolescents from Bedfordshire. When adjusting for dietary intake, CRF was also associated with adiposity but PA was not. The prevalence of misreporting varied depending on the method used to assess the validity of dietary intakes; between 23% and 31% increasing to 62.1% (in overweight) of adolescents under reported energy intakes and up to 11.1% over reported. The novel application of a triaxial accelerometer to measure EE resulted in more under and over reporters being identified than when compared to the widely used Goldberg equation. Increased dietary GI was associated with increased odds of having a high WC; however, associations between GL and other risk factors were less clear; no associations with risk were observed. Excluding dietary misreporters from analysis had important implications for these associations. Only after removal of misreporters by EI:EE(RT3) was a borderline significant positive association between GL and blood glucose (BG) revealed using multiple analysis of covariance (MANCOVA), that was not present in prior analyses. Increased GI (moderate vs low GI intake) was significantly associated with reduced high density lipoprotein cholesterol (HDL) and increased triglyceride (TG) levels (borderline significant) after removal of misreporters. In addition, using different PA thresholds to assess PA intensity resulted in different relationships between PA subcomponents and metabolic risk factors. Regardless of the threshold used, evidence suggested that limiting sedentary (SED) behaviour and engaging in moderate to vigorous PA (MVPA) is beneficial for blood pressure (BP) in this adolescent population. Additionally, irrespective of the threshold utilised, higher levels of vigorous PA (VPA) were associated with reduced odds of having a high clustered risk score and the associations observed between CRF and risk factors were stronger than those observed with PA. Despite a lack of significant improvement in individual metabolic risk factors as a result of the low GI (LGI) dietary intervention, there was a significant reduction in clustered risk score for the LGI group at week 12. A borderline significant improvement in glycated haemoglobin (HbA1c) was also observed as a result of the LGI intervention compared to those in the control group. Conversely, there appeared to be an unfavourable effect of the LGI diet on fasting insulin levels and thus the diet‟s impact on health overall is unclear. The small sample size of this randomised controlled trial (RCT) means that caution is required when interpreting the results. These data suggest that future research in this age group should target improvements in CRF and a lower dietary GI to reduce adiposity. Controlling for dietary misreporting appears to have a significant impact on associations of glycaemic CHO and cardiometabolic health and should be an important consideration of future research. The low GI intervention may be an effective approach for reducing glycaemic CHO, whilst maintaining a healthy macronutrient intake, in comparison to more restricted dietary regimens published in the literature. However, the impact of this regime needs to be confirmed utilising a larger sample of adolescents. This may provide a useful approach for future research aiming to assess the impact of reduced GI and GL.
    • The effects of caffeine on short-term, high-intensity exercise

      Doherty, Michael (University of BedfordshireUniversity of Bedfordshire, 2004-12)
      This aim of this series of studies was to investigate the effects of oral caffeine ingestion (5 mg . kg-1) on whole-body, short-term, high-intensity exercise (ST; representing an exercise intensity of between 100% -150% V02 max), an area that has received scant attention in the past. It was found that, in common with other 'open-ended' tests, one ST assessment, the maximal accumulated oxygen deficit (MAOD), appeared to lack both validity and reliability. Although traditional reliability markers of MAOD were favourable, the 95% limits of agreement were unacceptably large. In addition, the validity of MAOD was also found to be questionable because a study of elite runners revealed that a large proportion were unable to accomplish a plateau in the V02 -exercise intensity relationship. A follow-up study developed an original bespoke 'preloaded' ST cycling protocol that combined constant-rate exercise with an 'all-out' effort. This protocol appears to have several features that make it a more appropriate assessment to use in ergogenic studies than the MAOD. The work also considered the original, and as yet, undeveloped potential, for the assessment of rating of perceived exertion (RPE) during ST. It was shown for the first time that RPE (Borg scale; 6-20) could be used reliably during constant-rate ST. Three of the ten studies demonstrated that caffeine can be ergogenic during ST, with improvements averaging 11 % (95% GI, 7.4% -14.5%) above placebo treatment. In addition, the caffeine studies contributed to a meta-analysis of the effects of caffeine on test outcome that resulted in an effect size greater than zero, with 95% confidence intervals not crossing zero. The studies have examined potential physiological and metabolic mechanisms of action that may help explain caffeine's impact on ST. These suggest that there is some evidence that caffeine both stimulates anaerobic glycolysis and reduces electrolyte disturbance during ST. Finally this work has demonstrated for the first time that the perceptual response during constant-rate ST, as measured by RPE, is blunted following caffeine ingestion. It is concluded that caffeine is ergogenic during ST, and that while the exact mechanism(s) of action remains unknown, one consistent test outcome is a reduction in RPE during constant-rate ST.
    • The effects of contrast water therapy and hot water immersion on the signs and symptoms of exercise-induced muscle damage following a downhill run

      Erasmus, Brittany (University of BedfordshireUniversity of Bedfordshire, 2014-04)
      Eccentric exercise typically induces muscle damage that can cause detrimental effects on an athlete’s performance. Therefore, it is vital to find a recovery strategy that will increase the rate of recovery, alleviate the signs and symptoms associated with exercise-induced muscle damage, and return the athlete to peak performance levels as quickly as possible. Water immersion, in the form of cold water immersion, hot water immersion and contrast water therapy are becoming increasingly popular interventions used to alleviate the signs and symptoms of exercise-induced muscle damage and improve recovery after eccentric exercise. The purpose of the study was to determine the effects of contrast water therapy and hot water immersion on the signs and symptoms of exercise-induced muscle damage using indirect markers of muscle damage. These markers of muscle damage include; perceived muscle soreness, pressure pain threshold, squat jump, range of motion, flexibility, creatine kinase and limb circumference and are used in this study as a measure of the signs and symptoms of exercise-induced muscle damage. The purpose of Chapter 4 (Study 1) was to determine the reproducibility of these indirect markers of muscle damage. Overall, no systematic bias was found for any of the variables apart from creatine kinase. However, several performance and functional measurement tools; creatine kinase, flexibility, perceived soreness and pressure pain threshold exhibited low reproducibility, whilst creatine kinase, range of motion, perceived muscle soreness, limb circumference, and pressure pain threshold demonstrated good to excellent reliability however, squat jump demonstrated good xv reliability. With several of the indirect markers of muscle damage demonstrating poor to low reliability, discretion is advised when using these measures to detect systematic change, as the low reproducibility may obscure the true experimental results. The purpose of Chapter 5 (Study 2) was to determine the effects of contrast water therapy, and hot water immersion on the signs and symptoms of exercise-induced muscle damage. There is a plethora of studies aimed at determining the effects of cold water immersion and contrast water therapy on the signs and symptoms of exercise-induced muscle damage (Bailey et al., 2007, Eston and Peter., 1999a, Halson et al., 2008., Ingram et al., 2009, Montgomery et al., 2008, Vaile et al., 2008b). However, limited studies have determined the effects of hot water immersion alone (Kuligowski et al., 1998). All participants in this study completed a muscle damaging protocol which consisted of a 40 minute downhill run. Subsequently, participants were either treated with hot water immersion, contrast water therapy, or no water immersion for 40 minutes at 0 hours, 24 hours, and 48 hours post downhill run. Perceived muscle soreness, pressure pain threshold, squat jump, range of motion, flexibility, limb circumference and creatine kinase were measured on five separate occasions (pre-downhill run, immediately post downhill run, 24, 48 and 72 hours post downhill run). Results demonstrated that contrast water therapy had an improved effect on alleviating several signs and symptoms of exercise-induced muscle damage. Briefly, peak decrements at 24 hours in creatine kinase, pressure pain threshold, flexibility, squat jump, and perceived muscle soreness were found in the hot water immersion group and contrast water immersion groups, where as peak decrements at 48 hours for pressure pain threshold, flexibility, and squat jump were found in the control group.
    • Environmental stressors and cooling interventions on simulated soccer performance

      Aldous, Jeffrey William Frederick (University of BedfordshireUniversity of Bedfordshire, 2016-01)
      The increasing globalization of elite soccer match-play means that soccer players are likely to compete in hot, hypoxic and hot-hypoxic environments over a season. Soccer match-play studies have identified a marked decline in soccer-specific physical performance in the heat and hypoxia due to increasing body temperatures and a reduction in partial pressure of oxygen (PO2), respectively. As hot environments are more prevalent in elite soccer match-play, cooling strategies have been assessed within the literature in an attempt to alleviate these heat-induced- decrements. However, utilising a soccer match-play design makes environmental and interventional inferences difficult to ascertain, as a plethora of match factors and adaptive pacing strategies cause high variability in key physical performance measures within soccer match-play. Therefore, the three experiments within thesis aimed to assess the reliability and validity of a non-motorised treadmill (NMT) based soccer-specific simulation [intermittent Soccer Performance Test - (iSPT)], to enable the reliable investigation of environmental stress on soccer performance and the efficacy of pre- and half-time-cooling to attenuate any heat- induced-decrements. The purpose of experiment 1 was to investigate the reliability and validity of iSPT which utilised a novel speed component called a ‘variable run’. This speed component quantified the distance covered at a self-selected speed above the second ventilatory threshold (VT2speed), which attempted to delimit a ‘high-intensity’ threshold. Twenty male University soccer players completed one maximal oxygen (O2) uptake (V̇ O2max ) test, three familiarisation (FAM) sessions and one peak speed assessment (PSA) on the NMT, before completing the iSPT twice (iSPT1 and iSPT2). The total distance, sprint distance and high-speed distance covered were 8,952 ± 476 m, 1,000 ± 74 m and 2156 ± 140 m, respectively. No significant difference (p>0.05) was found between repeated trials of the iSPT for all physical performance measures and physiological responses. Reliability measures between iSPT1 and iSPT2 showed good agreement [Coefficient of variation: <4.6%; Intraclass correlation: >0.80] compared with statistical guidelines. Furthermore, the variable run phase showed high speed running capacity was significantly decreased (p<0.05) in the last 15 min compared to the first 15 min, showing parity with previous match-play data. Experiment 1 validated the iSPT as a NMT based soccer- specific simulation compared to previous match-play data, and is a reliable tool for assessing and monitoring the physical performance and physiological responses in soccer players. Successfully completing the aim of experiment 1 facilitated the quantification of hot (HOT), hypoxia (HYP) and hot-hypoxia (HH) mediated decrements on maximal soccer-specific performance in experiment 2. Twelve male University soccer players completed three FAM sessions, one PSA and four randomised crossover experimental trials of the intermittent Soccer Performance Test (iSPT) in normoxic-temperate (CON: 18oC 50% rH), HOT (30oC; 50% rH), HYP (1,000m; 18oC 50% rH) and HH (1,000m; 30oC; 50% rH). Physical performance and its performance decrements, body temperatures [rectal (Tre), skin (Tsk) and estimated muscle temperature (Tmu)], heart rate (HR), arterial blood oxygen saturation (SaO2), perceived exertion, thermal sensation (TS), body mass changes, blood lactate (Bla) and plasma volume were all measured. Performance decrements were similar in HOT and HYP [total distance (-4%), high- speed distance (~-8%) and variable run distance (~-12%) covered] and exacerbated in HH [total distance (-9%), high-speed distance (-15%) and variable run distance (-15%)] compared to CON. A 4% increase in peak sprint speed was present in HOT compared with CON and HYP and 7% greater in HH. The sprint distance covered was unchanged (p > 0.05) in HOT and HYP and only decreased in HH (-8%) compared with CON. Body mass (-2%), temperatures (+2- 5%) and TS (+18%) were altered in HOT. Furthermore, SaO2 (-8%) and HR (+3%) were changed in HYP. Similar changes in body mass and temperatures, HR, TS and SaO2 were evident in HH compared to HOT and HYP, however, Bla (p < 0.001) and plasma volume (p <0.001) were only significantly altered in HH. Perceived exertion was elevated (p < 0.05) by 7% in all conditions compared with CON. Regression analysis identified that absolute TS and absolute rise in Tsk and estimated Tmu (r = 0.82, r = 0.84 r = 0.82, respectively; p <0.05) predicted the hot-mediated-decrements in HOT. The hot, hypoxic and hot-hypoxic environments impaired physical performance during iSPT. Future interventions should address the increases in TS and body temperatures, to attenuate these decrements in physical performance. Experiment 3 of this thesis aimed to identify three pre- and half-time-cooling strategies to attenuate the heat-induced-decrements previously seen in experiment 2. Eight male University soccer players completed four randomised experimental trials of iSPT, three with cooling and one control (i.e. No pre- or half-time cooling: CON). The pre- and half-time-cooling interventions involved were 30-min or 15 min in duration, respectively. Ice slurry ingestion (SLURRY), ice packs (PACKS) covering the upper legs and mixed-methods (MM: PACKS and SLURRY) were utilised as the three cooling interventions. Physical performance and its performance decrements, body temperatures (Tre, Tsk and estimated Tmu), HR, perceived exertion, TS, body mass changes and Bla were all measured. Compared with CON, both PACKS and SLURRY pre-cooling significantly reduced (p > 0.05) central (Tre) and peripheral (Tsk and estimated Tmu) body temperatures prior to iSPT, respectively. However, body temperature and physical performance were unchanged during the first half of PACKS and SLURRY compared with CON. The MM pre-cooling significantly reduced all body temperatures and TS both prior to and during the first half which coincided with an improvement in total distance (+3%), high-speed distance (+4%) and variable run distance (+5%) covered. Half-time-cooling via PACKS, SLURRY and MM had no ergogenic effect (p> 0.05) upon physical performance in the second half, compared with CON. The 30 min of mixed-method pre-cooling, via ice packs placed upon the upper legs and ice slurry ingestion, significantly improved simulated soccer performance during the first half, however, future research should identify a valid half-time-cooling strategy to offer further improvements to physical performance in the second half. The main findings within this thesis revealed that the iSPT showed validity with previous soccer match-play data and strong reproducibility between two tests (iSPT1 and iSPT2). Furthermore, the variable run component showed efficacy as sensitive measure of the decrements in high-speed running capability. As the iSPT demonstrated low test-retest error compared with the statistical guidelines and previous NMT based soccer-specific simulations, any changes to physical performance can be attributed to an intervention and not the variability of the measure, unlike in soccer match-play situations. No difference was seen for all physical performance measures in both HOT and HYP, however, the heat and hypoxic-induced- decrements stem from increasing body temperatures and changes to both SaO2 and HR, respectively. Such decrements may have a detrimental effect upon the match outcome. These heat-induced-decrements were attenuated in the first half after 30 min of mixed-methods pre- cooling, however, the 15 min of mixed-methods half-time-cooling did not significantly improve any physical performance measure in the second half. The mixed-method pre-cooling strategy tested within this thesis could go some way in maintaining physical performance during the first half of soccer match-play in hot environments (~30oC). However, future laboratory based research within a controlled environment should look to assess different combinations, times and strategies of cooling which may be applicable to the time constraints associated with elite soccer.
    • The evolution of sports nutrition and its application to human performance

      Brewer, John (University of BedfordshireUniversity of Bedfordshire, 2014)
      This thesis summarises a series of academic publications that make a contribution to the field of sports nutrition over a period of 30 years. It begins with research in the field of carbohydrate and endurance sport reflecting the early era of research into carbohydrate and endurance performance, and evolves into studies investigating the impact of sports nutrition and hydration on team sports. It presents papers and other peer reviewed outputs that focus on the application of scientific knowledge to enhance human performance, whilst demonstrating the increasing awareness of the relative importance of carbohydrate and hydration in a range of both female and male team and individual sports. The thesis also highlights the challenge faced by the manufacturers of sports nutrition products in making use of advances in science to develop new and innovative products. The thematic nature of this thesis shows how sports nutrition continues to evolve. As science identifies new and legal means of enhancing human performance, so sport, athletes and coaches will demand more advanced and specialised approaches to refuelling and hydration. This thesis draws together findings from a series of publications which demonstrate how scientists, coaches, athletes and sports nutrition manufacturers need to work closely together to research, identify and interpret the next stages in an exciting and demanding area of research. It also reflects the scientific advancement in the field of sports nutrition over a thirty year period, identifies possible areas for future research, and the continued application of hydration and nutrition strategies to enhance male and female endurance and team sports.
    • Examining perfectionism in elite junior athletes : measurement and development issues

      Appleton, Paul Richard (University of BedfordshireUniversity of Bedfordshire, 2009)
      The major theme of the current thesis was the definition, measurement, and development of perfectionism in elite junior sport. The first purpose was to examine the psychometric properties associated with Hewitt and Flett’s (1991) Multidimensional Perfectionism Scale (MPS-HF) when complete by a sample of elite junior athletes. In study one, a confirmatory factor analysis failed to support the original structure of 45-item MPS-HF. Subsequent exploratory and confirmatory factor analyses revealed a more parsimonious 15-item factor structure representing self-oriented (SOP), socially prescribed (SPP), and other-oriented perfectionism (OOP). Having established a reconstituted version of the MPS-HF, a second purpose of the research programme was to consider the origins of perfectionism in elite junior athletes using a cross-sectional design. Initially, in study two a social learning model was supported, with 18%-26% of variance in athletes’ perfectionism predicted by parents’ perfectionism. Building upon this finding in study three, a structural equation model revealed that parenting styles, including empathy and psychological control, mediated the parent-athletic child SPP relationship. In study four, a significant pathway emerged between parents’ achievement goals and athletes’ dispositional perfectionism, offering support for a social expectations model of perfectionism development. Specifically, parents’ task and ego orientations were positively associated with athletes’ SOP. In contrast, athletes’ SPP was predicted by parents’ ego orientation. Study four also demonstrated the nature and form of motivational regulation associated with athletes’ SOP and SPP. That is, a pathway emerged between athletes’ SPP and controlled forms of regulation, while athletes’ SOP was correlated with self-determined and controlled motivation. Finally, in study five, the coach-created motivational climate accounted for approximately 19% of variance in athletes’ perfectionistic cognitions, highlighting the role of additional social agents in the development of athletes’ perfectionism. The results of this research programme contribute to existing knowledge of perfectionism by forwarding reliable measures of SOP and SPP for employment in sport, and revealing a complex array of pathways that underpin the development of perfectionism in elite junior athletes. Ultimately, by preventing the occurrence of such pathways, athletic children may be protected from the perils of perfectionism.
    • An in vitro model for assessment of skeletal muscle adaptation following exercise related physiological cues

      Player, Darren James (University of BedfordshireUniversity of Bedfordshire, 2013-10)
      The aim of this Thesis was to further characterise and utilise an in vitro skeletal muscle (SkM) model, to investigate its potential use in further understanding the cellular and molecular adaptations to exercise in vivo. Candidate genes and proteins have been identified using in vivo, ex vivo and targeted in vitro experiments, however the complete picture of these molecular mechanisms are far from understood. Furthermore, the extent to which mechanical signals contribute to the intra-cellular mechanisms associated with exercise is also underinvesitgated. To this end, developing an in vitro model of SkM that can recapitulate in vivo SkM and respond to mechanical stimulation in a similar way to exercise will provide a means to begin to delineate the complex cellular and molecular regulation of SkM. The initial investigation (Chapter 3) characterised an optimal seeding density and culture period of C2C12 myoblasts within a 3 ml collagen gel. These data provided support for the use of collagen constructs seeded at 4 x 106 cells/ml, with no statistical differences observed in peak force, rate of force development and relative force compared to other seeding densities examined (table 3-2, all p > 0.05). However the use of 4 x 106 cells/ml supports previous data in a larger construct volume model, whilst the highest cell density possible in the system increases cell-cell contact required for fusion. Immunohistochemical and gene expression analyses provided evidence for the fusion of single seeded myoblasts into multinucleate myotubes, demonstrating an in vivo-like architecture. Chapter 4 presented data towards the characterisation and use of two distinct cyclical stretch regimens with respect to the acute biochemical and transcriptional responses. Data revealed increases in peak media lactate and reductions in peak media glucose, following cyclical stetch compared to control (p = 0.000 and p = 0.001 respectively, Fig. 4-2). Changes in mtDNA (Fig. 4-5) and associated mRNA transcriptional signals (Fig. 4-7) were mode dependent.
    • An investigation into cardiometabolic risk in children and adolescents

      Bailey, Daniel Paul; University of Bedfordshire (University of BedfordshireUniversity of Bedfordshire, 2012-02)
      The principle aim of this work was to provide an insight into the prevalence of the metabolic syndrome (MetS) in children and adolescents and to examine the associations of body composition measures, cardiorespiratory fitness (CRF), and physical activity with cardiometabolic risk. The combined association of adiposity and CRF on cardiometabolic risk in youths is also explored, as is the association of CRF with potentially modifiable variables, such as physical activity. This work has shown that, dependent on the definition employed, MetS may be present in 2.3% to 9.8% of children and adolescents in Bedfordshire, UK. When applying modified Adult Treatment Panel III definitions (Cook et al. 2003; de Ferranti et al. 2004), the condition was significantly more prevalent in overweight compared to non-overweight youths. Backward regression analyses identified that only body mass index (BMI) explained significant amounts of variance in clustered cardiometabolic risk, although being overweight according to internationally proposed cut points for BMI, waist circumference (WC), and waist-to-height ratio conferred participants to increased risk compared to their non-overweight counterparts. Clustered risk was also elevated in children and adolescents with low levels of CRF compared to those with high levels, whereas time spent in moderate-to-vigorous physical activity and vigorous physical activity (VPA) held no association. When stratified into groups according to level of fatness (BMI z-score) and CRF, those with high fatness/low CRF generally exhibited the most unfavourable cardiometabolic risk profiles. Cardiometabolic risk was higher in the high fatness/low CRF group compared to those with low fatness/low CRF and low fatness/high CRF when excluding WC from the score, and those with low fatness/low CRF when including WC in the score. Multiple regression and ANCOVA revealed that increased visceral fatness (indirectly measured using WC) was associated with reduced CRF, while increased time spent in VPA was associated with elevated CRF. These data suggest that BMI may be the best simple measure of obesity to employ when exploring adiposity-related cardiometabolic in children and adolescents. In addition, results from this iv investigation indicate that low CRF and overweight/obesity may have deleterious effects on the cardiometabolic health of children and adolescents and that interventions to reduce risk may target decreases in fatness and improvements in CRF and VPA as standard.
    • An investigation of the Morganroth hypothesis to establish if heart adaptation is exercise specific

      Richards, Joanna C. (University of BedfordshireUniversity of Bedfordshire, 2012-11)
      The investigation of exercise specific left ventricular (LV) adaptations to training have been predominantly cross sectional in design. The purpose of the current thesis was to investigate LV adaptations to short term (6-9 weeks) training to establish if any changes are exercise specific. A correlation study was used to investigate correlations between cardiac variables and MAXOV2(study 1). Cardiac variables were found to be the strongest predictors for absolute MAXOV2, MAXOV2BM and MAXOV2FFM in cyclists compared to the total sample or sedentary group, predicting 79% (p<0.01), 70% (p<0.01) and 77% (p<0.01) of the variance, respectively. Secondly, it was found that when MAXOV2 was scaled to body mass (BM) or fat free mass (FFM) cardiac variables predicted less of the variance than for absolute MAXOV2, for all groups. Study 2 investigated the hypothesis that there would be no evidence of LV hypertrophy when there was no increase in FFM. This was achieved by taking sedentary participants through a resistance training programme of 6 weeks duration to control for increases in skeletal muscle hypertrophy. Both resting systolic blood pressure (sBP; p = 0.01, d = 1.19) and diastolic blood pressure (dBP; p = 0.029, d = 0.88) were significantly reduced following the 6 weeks resistance training. One repetition maximum (1RM) bench press significantly increased (p = 0.00, d = -1.44) as did 1 RM parallel squat strength (p = 0.00, d = -1.86), with no associated increases in relative FFM (p = 0.45) or absolute LM (p = 0.87). There was no adaptation to LV morphology (p>0.05), however early diastolic function changed with a significant decrease in peak E wave (p = 0.00, d = 1.94). Study 3 compared differences in the time course of the initial adaptations to LV structure and function during 9 weeks of aerobic, resistance and combination exercise ii training, to establish whether LV adaptations are exercise specific. The resistance and combination groups demonstrated increases in relative wall thickness (p = 0.021, ηp2 = 0.408; p = 0.004, d = -1.06, respectively). PWd also significantly increased in the combination group (p = 0.032, ηp2 = 0.301); however there were no structural adaptations evident in the aerobic group (p > 0.05). In contrast, the aerobic group demonstrated functional adaptations with a decrease in A wave (p = 0.44, d = 0.87) as did the combination group (p = 0.002, ηp2 = 0.407). The results of the training studies showed limited support for the Morganroth Hypothesis as structural adaptations demonstrated LV remodelling of the myocardial tissue, with no increase in LV mass. Further to this, combination training appears to have an additive effect of LV adaptations of both aerobic and resistance training.
    • Left ventricular diastolic mechanics in trained athletes during submaximal exercise using speckle tracking echocardiography

      Beaumont, Alexander (University of BedfordshireUniversity of Bedfordshire, 2015-12)
      This thesis investigated sport specific responses of diastolic mechanics at rest and during submaximal exercise. Two-dimensional speckle tracking echocardiography (STE) was used to assess diastolic mechanics at rest and whilst triathletes (TRI, n=9, 32 ± 7 years), long distance runners (LDR, n=7, 34 ± 3 years), resistance trained (RT, n=5, 24 ± 5 years) and untrained controls (CON, n=5, 29 ± 5 years) performed dynamic and static exercise. Cycling consisted of 5 minute stages at 30% and 60% maximum workload (Wmax), and leg extension involved 15 second contractions at 40% and 75% maximal voluntary isometric contraction (MVIC). Peak untwisting velocity (PUV), apical and basal rotation velocities did not differ between groups at rest or during exercise (p>0.05). PUV increased in TRI from rest to 30% and 60% Wmax (p<0.01), remained unchanged in LDR, RT and CON from rest to 30% (p>0.05, p<0.05, p>0.05, respectively) and 60% Wmax (p=0.018, p>0.05, p>0.05, respectively). PUV did not change from rest to 40% (p>0.05) and 75% MVIC in TRI, LDR, CON (p>0.05) and RT (p<0.05). These findings suggest diastolic mechanics do not differ at rest or during exercise based on sport specificity, yet mixed training (TRI) athletes demonstrate augmented diastolic mechanics during dynamic exercise.
    • Multidimensional perfectionism and motivation in sport : potential mediating and moderating variables

      Hill, Andrew P. (University of BedfordshireUniversity of Bedfordshire, 2009-10)
      Recent research has found that self-oriented and socially prescribed perfectionism have distinct consequences for athletes. The purpose of the thesis was to extend this research by further examining their motivational consequences for athletes and identifying the psychological mechanisms that explain their divergent consequences. The first two studies suggested that the positive relationship between socially prescribed perfectionism and athlete burnout was mediated by the tendency to engage in validation-seeking and utilise avoidant coping, whereas the inverse relationship between self-oriented perfectionism and athlete burnout was mediated by the tendency to utilise problem-focused coping and eschew avoidant coping. Because these initial studies provided little evidence to suggest that self-oriented perfectionism has negative psychological consequences for athletes, the nature of self-oriented perfectionism and its consequences were examined more closely in two subsequent studies. A comparative study examining similarities and differences in the correlates of selforiented perfectionism and conscientious achievement striving found that while both include a commitment to high standards, self-oriented perfectionism also includes a concern over mistakes, fear of failure and negative reactions to imperfection. An experimental study examining the response of student-athletes II higher in this dimension of perfectionism to successive failures further suggested that, in comparison to those with lower levels of self-oriented perfectionism, those with higher levels of self-oriented perfectionism experienced a more pronounced increase in threat following an initial failure and reported withdrawing effort from the subsequent performance. The final two studies suggest that the divergent consequences of these two dimensions of perfectionism may also be explained by differences in the controllability of sources of self-worth and evaluative standards. In addition, in some instances, perceptions of the achievement climate may influence the self-criticism experienced by perfectionists. Collectively, this series of studies suggest that socially prescribed perfectionism will invariably lead to motivational and psychological difficulties for athletes. In contrast, such difficulties may not be inevitable for those with higher levels of self-oriented perfectionism; however, it may render athletes vulnerable to psychological difficulties when personal standards are not meet.
    • Novel intervention to confer cellular tolerance: applications & mechanisms

      Tuttle, James A. (University of BedfordshireUniversity of Bedfordshire, 2014-11)
      Exercise in hot environments decreases the temperature gradient for heat loss to the external environment increasing internal heat storage. Work completed decreases and exertional heat illness risk increases. Heat acclimation (HA) programmes which last between 7 -10 d improve heat tolerance by reducing rectal temperature (Tre) during exercise. Thermotolerance is also improved. These adaptations enable work to be maintained for longer periods of time. Exertional heat illness risk is also decreased. However, HA is not logistically feasible during rapid redeployment of military, athletic, occupational and emergency worker populations to hot environments. Therefore, developing an acute preconditioning trial to enhance heat tolerance and thermotolerance could be advantageous. This thesis first determined the effect of treadmill gradient (flat or downhill running) and environmental conditions (temperate~ 20oe, 50 % relative humidity (RH) or hot conditions; 30°C, 50 % RH) on heat shock protein 72 mRNA (Hsp72 mRNA), heat shock protein 90 alpha mRNA (Hsp90a mRNA), glucose regulated protein 78 mRNA, glucose regulate protein 94 mRNA, exercising Tre and HR, Study 2 investigated whether an acute trial combining downhill running and hot environmental conditions (Hot downhill) elevated basal HSP72 concentrations, attenuated exercising Tre• HR, vastus lateralis (VL) and leukocyte Hsp72 mRNA and Hsp90a mRNA responses during an identical trial 7 d later. Downhill running and hot environmental conditions increased leukocyte Hsp72 mRNA, leukocyte Hsp90a mRNA, exercising Trc and DOMS further than flat running and temperate environmental conditions. Increased Hsp72 mRNA and Hsp90a mRNA were mainly exercising Tre and metabolic strain dependent. Exercising Tn; (at 30 min) and DOMS were reduced during or following the second hot downhill trial. Attenuated Hsp72 mRNA and Hsp90a mRNA responses within the VL and leukocytes also occurred. Basal VL HSP72 increased after the second hot downhill trial In conclusion, an acute hot downhill trial decreases exercising Tn: and DOMS during an identical trial 7 d later but basal HSP72 concentrations are not affected. Leukocyte Hsp72 mRNA and Hsp90a mRNA are valid surrogates of the VL response.
    • The relationship between stiffness, asymmetries and change of direction speed

      Maloney, Sean J. (University of Bedfordshire, 2016-02)
      Change of direction speed (CODS) is an important determinant of performance in many sports. Greater stiffness of the lower limb should be beneficial to CODS, but this had not been well investigated. The purpose of this thesis was to establish the relationship between vertical stiffness, vertical stiffness asymmetries and CODS, with a view to augmenting CODS performance. The pilot study and studies 1-2 sought to determine the most reliable and ecologically valid method to assess stiffness in athletes required to perform changes of direction. The pilot study reported that the use of ultrasonography to determine Achilles tendon stiffness did not demonstrate appropriate reliability for inclusion in subsequent studies. Coefficients of variation (CVs) in excess of 27% were reported during an isometric plantar flexion task. Study 1 reported that CVs for vertical stiffness were lower when assessed during unilateral drop jumping (~7%) than during bilateral drop jumping (~12%) or bilateral hopping (~14%). Study 2 reported that the expression of vertical stiffness (P = 0.033) and vertical stiffness symmetry angle (P = 0.006) was significantly different across three performance tasks: unilateral drop jumping, bilateral drop jumping and bilateral hopping. Asymmetry percentages between compliant and stiff limbs were 5.6% (P < 0.001; d: 0.22), 23.3% (P = 0.001; d = 0.86) and 12.4% (P = 0.001; d = 0.39), respectively. Given the findings of studies 1 and 2, this thesis demonstrated the reliability and validity of a novel method by which to assess vertical stiffness - the unilateral drop jump. This task was used in subsequent studies to measure vertical stiffness. Study 3 sought to determine if vertical stiffness and vertical stiffness asymmetries influenced CODS performance determined during a 90o cutting task. Multiple regression analyses reported that mean vertical stiffness and asymmetry in jump height explained 63% (r2 = 0.63; P = 0.001) of CODS performance. Study 3 was the first investigation to demonstrate the importance of vertical stiffness to CODS performance. Study 4 sought to determine if acute exercise interventions designed to augment vertical stiffness would improve CODS. Unilateral and bilateral ‘stiffness’ interventions were evaluated against a control condition. CODS performances following the unilateral intervention were significantly faster than control (1.7%; P= 0.011; d = -1.08), but not significantly faster than the bilateral intervention (1.0% faster; P = 0.14; d = -0.59). Versus control, vertical stiffness was 14% greater (P = 0.049; d = 0.39) following the unilateral intervention. Study 4 demonstrated that a novel unilateral ‘stiffness’ intervention improved vertical stiffness and CODS performance. This highlights that the potential applicability of unilateral stiffness interventions in the pre-performance preparation of athletes.
    • The role of the TGfU pedagogical approach in promoting physical activity levels during physical education lessons and beyond

      Smith, Lindsey Rachel (University of BedfordshireUniversity of Bedfordshire, 2010-10)
      The study was designed to initially determine levels of moderate-to-vigorous physical activity (MVPA) occurring during physical education in 11-12 year olds using appropriate objective methods. Subsequently, the potential of a pedagogical method; ‘teaching games for understanding’ to increase PA levels and self determined motivation during PE lessons, and habitual physical activity during leisure time was examined. The most reliable and valid PA measurement tool for the chosen age group was the RT3 ® triaxial accelerometer. PA levels during PE lessons fell short of the recommended 50% (20 minute) criterion, with children accumulating 16.4 ± 2.3 minutes (44.9 ± 5.6%) of mean MVPA during lesson time. Seven day habitual activity monitoring revealed that time spent in MVPA on a PE day was significantly higher (P <0.05) than on a weekend day. This study also highlighted that on non PE days the lack of PE-related activity was not compensated by engagement in other activity. An investigation into the effects of a 12 week TGfU pedagogical strategy on MVPA and elements of Self Determination Theory during PE lessons revealed that boys assigned to the intervention displayed significantly higher (P <0.01) levels of MVPA, and significantly higher levels of autonomy (P < 0.05) post-intervention versus the control group. In addition, a non significant trend for an increase in habitual PA for boys assigned to the intervention lessons was revealed. No significant differences were displayed in the constructs of the TPB pre-post intervention and no significant benefits of TGfU were noted for girls. The reported increases in MVPA and levels of autonomy during PE lessons in boys using a TGfU approach are novel and promising. However it is suggested that future research incorporates such strategies in a health-promoting PE environment in addition to the traditional skills-based activities. This may have potential in enhancing MVPA during PE in girls and boys, and may promote greater transference to habitual physical activity levels. The potential for self determined environments positively impacting upon motivation and intentions to be physically active both during and outside of PE lessons warrants further exploration but over longer time periods.
    • Tissue oxygenation response to systemic and localised hypoxia during intermittent isometric contractions.

      Gooch, Simon (University of BedfordshireUniversity of Bedfordshire, 2015-04)
      The use of either blood flow restriction (BFR) and systemic hypoxia (HYP) during resistance exercise has been shown to increase hypertrophy and strength to a greater extent compared to traditional resistance exercise alone. However, the mechanisms underpinning these enhanced adaptations remain to be elucidated. Differences in skeletal muscle oxygenation may be one of several factors that leads to increased hypertrophy and strength with BFR and HYP. Nevertheless, this has been sparsely investigated. High intensity resistance exercise is also accompanied by an increase in oxidative stress, providing beneficial hypertrophic signalling. The addition of BFR has been observed to decrease these beneficial signals and the effect of HYP is unknown. PURPOSE: To investigate the skeletal muscle oxygenation and oxidative stress response during moderate intensity rhythmic isometric handgrip exercise with BFR, HYP, and resistance exercise alone. In addition, to observe the perceived pain (PP) response to these novel exercise modalities during exercise. METHODS: Eight recreationally active males (23 ± 1 yr, 76 ± 10 kg, 175 ± 6 cm) completed three sets of 45 repetitions of isometric handgrip exercise (60% 1RM) either with BFR (80 mmHg proximal cuff) 5 minutes pre and during exercise, with HYP (14% O2) 5 minutes pre and during exercise or with resistance exercise alone (CON). Exercise was completed in a supine position, with one-minute rest in-between sets. Skeletal muscle oxygenation was measured throughout using a dual wave near infrared spectroscopy (NIRS) device placed on the forearm flexors, with output variables of tissue saturation index (TSI), oxygenated haemoglobin (O2Hb), de-oxygenated haemoglobin (HHb) and total haemoglobin (THb). NIRS variables were reported as a delta from a pre-exercise control period and represented a change from baseline. Oxidative stress was measured in whole blood via glutathione ratio (GSSG:GTSH). PP was measured during each exercise set with a visual analogue scale. RESULTS: TSI was lower in BFR (-11.5 ± 10.3 %) compared to CON (-1.3 ± 5.1%, p = 0.007) and lower with no significant difference compared to HYP (-4.5 ± 5.1 %, p = 0.059), there was no difference between CON and HYP (p > 0.05). There was no difference in O2Hb between conditions (p >0.84). HHb was higher in BFR (13.9 ± 5.1 μmol) compared to both CON (2.06 ± 5.87 μmol, p = 0.001) and HYP (6.83 ± 6.11 μmol, p = 0.042), with no difference between CON and HYP (p > 0.05). THb was significantly higher in BFR (9.41 ± 9.54 μmol) compared to both CON (-1.22 ± 5.50 μmol, p = 0.001) and HYP (1.59 ± 5.04 μmol, p = 0.008), with no difference between CON and HYP (p > 0.05). There was no increase in GSSG:GTSH pre-post exercise with no significant difference between conditions (p > 0.085). PP was higher in the BFR condition (6 ± 1 a.u) compared to CON (2 ± 2 a.u, p = 0.001) and HYP (2 ± 2 a.u, p = 0.001), with no difference between CON and HYP (p > 0.05). CONCLUSION: Moderate intensity rhythmic isometric handgrip exercise with BFR results in an increased blood volume (THb), decreased clearance of HHb and lower TSI compared to HYP and CON, however O2Hb delivery remains similar between conditions. The differences in skeletal muscle oxygenation with the addition of BFR to resistance exercise provide further insight into the mechanisms acute of BFR; however, further investigation is required with over a prolonged period of training. The current protocol did not elicit a whole blood oxidative stress response in the form of increased GSSG:TGSH, therefore the role of oxidative stress could not be determined.
    • The use of acute responses of endocrine and immune biomarkers to highlight overreaching

      Leal, Diogo Luis Campos Vaz (University of BedfordshireUniversity of Bedfordshire, 2017-09)
      The action of overtraining may lead to the different states of overreaching or the overtraining syndrome (OTS). Chronic maladaptation in endocrine and immune mechanisms, and performance decrements occur with the incidence of these states. Circulating cortisol and testosterone have been proposed as endocrine markers of overreaching/OTS. Salivary measurements of these hormones have been used as a non-invasive surrogate for circulating levels. Chapter 4 (study 1) on this Thesis examined the influence of consuming water 10 min, 5 min and 1 min before providing a saliva sample in diluting saliva and consequently providing invalid salivary cortisol and testosterone concentration levels. No trial effect was found. However, exercise-induced salivary cortisol and testosterone significantly elevated in response to the 10 min and 5 min trials only, with lower absolute-changes observed in the 1 min trial. No differences were found in the resting samples. It was suggested that consuming water up to 5 min before providing a saliva sample does not appear to influence the hormone concentrations at rest and during exercise. However, the recommended guidelines for saliva collection have been followed in the subsequent studies. Chapter 5 (study 2) examined the reproducibility of salivary cortisol and testosterone responses to a 30-min cycle named as the 55/80. This test has been proposed as a suitable indicator of hormonal alterations associated with overreaching/OTS. Reproducibility of salivary cortisol and testosterone to the 55/80 was confirmed by determining intra-individual coefficients of variation (CVi). However, the 55/80 is a cycle test and therefore, may not be appropriate for runners. Chapter 6 (study 3) focused on designing a 30-min, running bout (i.e. the RPEtreadmill) to reproduce the effects of the 55/80. The RPEtreadmill is a self-paced test and therefore, will not require aVO2maxtest to determine exercise intensities. An acute elevation of plasma and salivary testosterone, but not cortisol was observed in response to the RPEtreadmill. These responses have been shown to be reproducible. The data from Chapter 6 suggest that the RPEtreadmill may be a suitable tool to indicate hormonal alterations associated with overreaching/OTS. This led to the design of study 4 (Chapter 7). Plasma and salivary cortisol and testosterone responses were examined before and after a 12-day intensified-training period. Immunity markers (specifically salivary immunoglobulin A (SIgA), leucocyte subset proliferation and phagocytic activity) were examined before and after training. Plasma and salivary cortisol were unaffected by acute exercise and training. However, testosterone elevated to the RPEtreadmill Pre-Training, and these responses were reduced Post-Training. Total leucocytes and mucosal immunity were unaffected by exercise and training. However, increased upper respiratory tract infection symptoms were found Post-Training. Baseline phagocytic function was 47% lower Post-Training. This Thesis suggests that testosterone may be a more reliable exercise-stress marker. Moreover, the RPEtreadmill may be a suitable tool to highlight alterations in testosterone when in an overreached state in an attempt to avoid the incidence of OTS, and that this tool may be practically applied in the field of exercise science. Additionally, this Thesis shows that a 12-day intensified-training period induced a marked decrease in phagocytic responses, and therefore using the RPEtreadmill to highlight overreaching may be important to also prevent further impairments in immunity status.