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A Dissertation Submitted to the Department of Physiology, University of the Witwatersrand,Johannesburg for the Degree of Master ot Science / Extensive disruption of muscle fibres has been shown to occur after short term eccentric exercise where high mechanical forces are generated. This study tested whether downhill running acts as a stimulus for inducing eccentric damage, and results in greater muscle damage and deterioration in muscular performance than an equal workload of uphill running. The study aimed at determining whether an adaptation or training effect takes place such that the muscle is more resistant to the damaging effects of a repeated bout of the same exercise. In. addition, the study aimed at determining whether the lower muscle volumes and forces of muscular contractions in females compared to males, makes females less susceptible to the damaging effects of eccentric contraction.(Abbreviation abstract) / Andrew Chakane 2019

Aim: To undertake exploratory work examining the relationship between menopausal symptoms, body image, exercise and wellbeing. Method: A mixed methods approach was used, including a systematic scoping review, the development of a synchronous text-based online interviewing tool; a qualitative Interpretative Phenomenological Analysis study, and mixed methods study. Results: The review showed that women’s experiences of the menopause and body image can be both positive and negative simultaneously, which has implications for the way these concepts are quantitatively measured. A synchronous online interviewing tool is an additional method to be added to the researchers’ tool kit, especially if the topic is sensitive and an extra level of anonymity is needed. The IPA study focused on experiences of body image concerns and identified a range of ways menopausal women cope with such changes. Through Structural Equation Modelling and interviews, we identified that menopausal symptoms may act as a barrier to exercise participation by decreasing a woman’s subjective vitality, and reducing perceptions of attractiveness, life satisfaction and self-esteem. Conclusion: Health psychology of the menopausal transition is in its infancy. It is not only important to consider methods to reduce symptoms, but also the impact symptoms have on health behaviour, body image and wellbeing.

Observations of human behaviour show a tendency for avoiding energy expenditure through stair climbing where possible. Similarities between demographic influences in stair avoidance and explicit perceptions of geographical slant outlined in the ‘economy of action’ account (Proffitt, 2006) suggest that this avoidance behaviour might be due to a perceptual bias. Chapter two of this thesis investigated measures of slant perception linked to action. It appears that these ‘haptic’ measures tap into a perceptual process that is more in touch with the physical reality of the environment than conscious awareness. Chapter four demonstrated that fundamentals of the economy of action account generalise to the perception of staircases, and to a newly developed laboratory setting. Depletion of energetic resources, manipulated through fatigue, resulted in steeper explicit estimates of staircase steepness. In reaction to published criticisms of the methodology used in this field, chapter five took a new approach to testing the effect of resources on perception. Two quasi-experimental field studies, designed to circumvent methodological issues challenging the validity of previous studies, demonstrated that available energy resources affects consciously perceived steepness in the built environment. Chapters six and seven built on this by testing the economy of action account as a model that explains stair avoidance behaviour. Encouragingly, across two different points-of-choice between stair climbing and avoidance, explicit measures of perceived geographical slant were linked to reported prior stair climbing behaviour at one site (chapter six) and objectively measured behaviour at another (chapter seven). Collectively, these findings suggest that available energetic resources dictate the exaggeration of perceived geographical slant experienced at an individual level, and that this in turn influences stair choice behaviour, biasing those with less resources towards stair avoidance and energy preservation.

This work investigated relationships between neck pain, cervical proprioception and ocular motor performance. Systematic literature reviews identified moderate quality evidence for greater cervical joint positioning errors (JPE) in the transverse plane among participants with whiplash, but low-to-very low quality evidence for participants with non-traumatic neck pain, and for other cervical and ocular tests. Limited low quality evidence indicated little correlation between performance across tests, questioning their construct validity for cervical proprioception. Test-retest studies established adequate intra-examiner reliability of a smooth-pursuit (SPNT) test, a novel, non-predictable ocular tracking test and of cervical JPE and cervico-cephalic kinesthesia tests. A cross-sectional study found impaired non-predictable ocular tracking performance in mechanical neck pain, compared with healthy participants. The construct validity of this, and of existing tests, was evaluated by examining convergence of correlation in their performance. In healthy participants, convergence between cervical JPE, cervico-cephalic kinesthesia and ocular tracking tests, indicated common neurological processes. In the neck pain group there was convergence only between the cervico-cephalic kinesthesia and ocular tracking tests. A theoretical model suggested that impaired cervical proprioception or cognitive functions underlie deficits in neck pain, while adaptations in vestibular gain or efference copy underlie the absence of impairment in the cervical JPE test.

Sarcopenia negatively impacts physical function and health. Although the mechanisms underpinning sarcopenia are unclear, a blunted response to anabolic stimuli is observed. Accordingly, Chapter 2 explored how dose, timing, distribution and source of dietary protein intake differed between healthy young and older individuals. We showed that, whilst the recommended dietary allowance for protein was met by most individuals, total protein intake was lower and unevenly distributed across meals in old. The observation of sub-optimal protein intakes in older individuals has important implications for skeletal muscle maintenance. Therefore, in Chapter 3 we investigated the muscle anabolic response in young lean, old lean and obese old individuals to a suboptimal protein dose. Whilst young lean and, to a lesser extent, old lean significantly increased postprandial myofibrillar protein synthesis (MyoPS), this response was blunted in obese old. Furthermore, MyoPS correlated significantly with step count and leg fat mass in old. Based on the age-related decrease in MyoPS, we assessed the ability of phosphatidic acid (PA) to increase MyoPS at rest and after exercise in Chapter 4. Compared to a placebo treatment, MyoPS was blunted upon PA consumption in the late phase of resistance exercise recovery and was probably due to impaired anabolic signaling.

This thesis investigated markers of oxidative stress and immunosenescence in healthy adults. The results presented represent several novel findings which support the notion that oxidative stress and infection with micro-organisms shape our biology and can accelerate aspects of ageing. Acute exercise of high intensity was shown to cause alterations in the cellular composition of blood, which was most pronounced in lymphocyte sub-populations important for immunosurveillance. This exercise also resulted in increased markers of oxidative stress in lymphocytes, and resulted in a whole body oxidative stress, which was more pronounced and prolonged, following ultra-endurance exercise. Studies also showed that infection with a highly prevalent and asymptomatic herpes virus, Cytomegalovirus (CMV), shapes our immune biology in two significant ways. First, CMV amplified the magnitude and kinetics of lymphocyte responses to exercise, which could potentially facilitate immune surveillance, or aggravate inflammatory processes. Second, CMV was seen to drive the development of an ‘Immune Risk Profile’ in young adults, characterised by increased inflammatory activity and smaller responses to vaccination. These outcomes are associated with frailty, cognitive decline, and mortality in the elderly.

Physical inactivity is associated with dysregulation of intramuscular triglyceride (IMTG) metabolism leading to the accumulation of fatty acid metabolites and insulin resistance. This thesis aims to provide new information concerning the role of a subset of proteins associated with the metabolic regulation of IMTG-containing lipid droplets (LDs), known as the perilipin (PLIN) proteins, predominantly using immunofluorescence microscopy. Chapter 2 demonstrates that PLIN2-containing LDs are preferentially targeted for breakdown during moderate-intensity exercise in lean, sedentary males. Chapter 3 reveals that 6 months of endurance training (ET) in obese type 2 diabetes patients enhances PLIN2 content in type I fibres. Chapter 4 demonstrates that improvements in IMTG metabolism, including increased expression of PLIN2 and PLIN5, occur in response to both ET and sprint interval training (SIT) in lean, sedentary males. In Chapter 5 data is provided to show that RT also improves IMTG metabolism and insulin sensitivity in lean, sedentary males. Chapter 6 documents the effectiveness of a new constant-workload SIT protocol with regards to improving insulin sensitivity in obese individuals. In conclusion, this thesis generates novel data that contributes to our understanding of the underlying mechanisms that govern the relationship between IMTG metabolism and insulin sensitivity.

The metabolic syndrome is highly prevalent in western society, and the numbers affected by obesity and diabetes continue to rise. This thesis reviews the mechanisms at play and the gaps in the literature that, if filled, may increase knowledge of treatment regimes for affected individuals. Experimentally, it was demonstrated that the oral glucose tolerance test can be a reliable tool to measure insulin sensitivity following adequate dietary and exercise control. Acute and chronic cinnamon ingestion was shown to improve insulin sensitivity. Feeding frequency was found to alter insulin and ghrelin responses and relationships following mixed-meal ingestion. And finally, postprandial lipaemia was found to be attenuated for up to 24 hours following moderate-intensity exercise, illustrating the requirement of daily exercise. In summary, oral glucose tolerance tests are suitable for experimental interventions; and the clinical management of factors associated with the metabolic syndrome should perhaps consider dietary supplements, meal frequency, and exercise timing in addition to the traditional dietary and physical activity guidelines currently in practice.

With the prevalence of obesity reaching epidemic levels both within the UK and worldwide there is an urgent need to explore ways in which to stem its burden on our society. There is a large body of research examining the positive effects of dietary and physical activity interventions for weight loss success, however much less is known regarding the psychological aspects, in particular the self-regulatory factors that contribute to both weight loss and weight maintenance success and failure. The current thesis examines these factors through four studies. Study one highlighted the factors related to success and failure in weight maintenance. Study two investigated the characteristics contributing to successful attainment of a weight loss and a non weight loss goal simultaneously. Study three explored the factors related to dietary lapse occurrence. Building on the previous studies, study four consisted of a self-regulatory skills intervention to improve weight-related outcomes. Results highlight the role of temptations and lapse occurrence and the threat they pose to weight loss and weight maintenance success. In addition, the current thesis outlines the need to not only identify influential self-regulatory factors but also to develop these factors in order to promote weight loss success.