Worldwide, overweight/obesity and associated chronic diseases such as type 2 diabetes, have reached epidemic proportions. Statistics show that overweight/obesity and chronic disease is prevalent amongst adults and children in South Africa. In addition to chronic disease/non-communicable diseases, overweight/obesity has been shown to alter immune and sympathetic activation. There is limited information on immune function (mucosal) and sympathetic activation on children both internationally and nationally and in particular investigating these parameters using non-invasive methods such as salivary biomarkers. The aim of this thesis was to investigate the levels of salivary biomarkers of immune function and sympathetic activation in children and determine the association with overweight/obesity, cardiorespiratory fitness (CRF) and increased physical activity (PA). Methods This thesis is divided into six chapters. These include an introductory chapter (Chapter One), a review of the literature (Chapter Two) and then three chapters that are written in article format and that have each been submitted to accredited journals for publication. Chapter Three is a review article that discusses salivary biomarkers in children as they relate to exercise, PA and obesity. Chapter Four is a study that examined salivary biomarkers of mucosal immunity and sympathetic activation as predicted by age, body composition and cardiorespiratory variables in one hundred and thirty-two black South African children (age 10.05 ± 1.68y, 74 females, 58 males). Chapter Five is a study that investigated salivary biomarkers of mucosal immunity and sympathetic activation in response to 12 weeks of soccer training in thirty-four black male South African children (11 – 13y) from a youth football training academy. Chapter Six includes a summary of the research findings, conclusions and well as recommendations for future research. A review of the literature revealed that participation in regular moderate intensity PA or exercise appears to enhance mucosal immunity (increases salivary IgA (sIgA)) in preadolescent children. In contrast, poor fitness and inactivity as well as strenuous training appear to compromise the mucosal immune system thereby increasing the risk of upper respiratory tract infections (URTIs). Children reporting higher levels of body fat and with a greater BMI appear to have lower sIgA levels and a greater incidence of infections. The limited research examining salivary C-reactive protein (sCRP) suggests a strong association between poor cardio-respiratory fitness (CRF) and/or overweight/obesity and inflammatory status in children based on elevated sCRP levels. Research surrounding salivary alpha-amylase (sAA) indicates that exercise can result in a marked increase in sAA as seen by an increase sympathetic activity via increased adrenergic activity in the salivary glands. The limited research suggests exercise may also pose a high stress on young athletes as seen with an increase in sAA. Additionally it appears that BMI may be a strong predictor of stress-induced sAA increases in children. Greater hypothalamic pituitary adrenal (HPA) axis response, as seen by increases in salivary cortisol, appear to be influenced greatly by increases in obesity. Higher salivary cortisol secretions have been observed in obese versus lean children in response to exercise. School study: The outcomes of the one-way ANOVAs examining the differences by body mass index (BMI) categories showed there were significant differences in weight (F = 83.64, df = 2, 129, P < 0.0001), BMI (F = 193.36, df = 2, 129, P < 0.0001), waist-to-hip ratio (F = 193.36, df = 2, 129, P < 0.0001), body fat percentage (F = 336.98, df = 2, 129, P = 0.0001), SBP (F = 5.72, df = 2, 129, P = 0.0042), DBP (F = 291.76, df = 2, 129, P < 0.0001), VO2max (F = 521.00, df = 2, 129, P < 0.0001), sAA concentration (F = 17.05, df = 2, 129, P < 0.0001), sAA secretion rate (F = 15.15, df = 2, 129, P < 0.0001), sIgA concentration (F = 11.30, df = 2, 129, P < 0.0001), and sIgA secretion rate (F = 8.08, df = 2, 129, P = 0.0005), between children of different BMI categories. According to the CDC-BMI-for-age standards, the participants were grouped into the following CDC-BMI-for-age categories: normal weight (< 85th percentile), overweight (≥ 85th percentile to < 95th percentile), and obese (≥ 95th percentile) (Ogden and Flegal, 2010). Tukey’s post hoc analyses revealed that obese children had significantly (P < 0.01) higher weight, BMI, body fat percentage, DBP, SBP, sAA concentration and secretion rate, compared to overweight and normal weight children, as well as a significantly lower aerobic capacity (VO2max) than both normal (P < 0.001) weight and overweight (P < 0.05) children. In addition, sIgA concentration and secretion rate were significantly lower between normal weight and obese children (P < 0.01). Multiple linear regression revealed that BMI, DBP and VO2max predicted sAA. BMI (P = 0.04) and DBP (P = 0.04) were found to be independent predictors of sAA concentration. Age and BMI category predicted sIgA secretion rate. BMI category (P = 0.0006) was found to be an independent predictor of sIgA secretion rate. Soccer study: Significant differences after 12 weeks of soccer specific training were found to be significant between pre vs. post for BMI (P =0.034), waist-to-hip ratio (P = 0.046), age (P < 0.0001), height (P < 0.0001), body fat % (P < 0.0001) and LMM (P < 0.0001). Decreases in BMI, waist-to-hip ratio, body fat % and LMM were found while age and height increased throughout the 12 weeks. Significant differences were also found between sIgA secretion rate pre vs. post training (P =0.025) as increases in these values pre to post were observed. Conclusions The results from the studies on the school children and soccer players suggested that mucosal immune function and sympathetic activation appear to be affected by body composition, CRF and chronic exercise training. The main findings for the school study revealed that BMI, DBP and VO2 predict sAA and that age and BMI category predict sIgA. This study also found that obesity (based on BMI) has a major role to play and that obese children have elevated sAA, lowered sIgA, and poor CRF. The finding of an increase in sIgA secretion rate in the soccer study suggested that a structured 12 week exercise programme can elevate mucosal immune function in youth soccer players. The underlying mechanism responsible may be an exercise-induced increase in the transport of sIgA across the mucosal epithelium and/or enhanced production of IgA in the mucosa via mediating cytokines. The literature review demonstrated that PA and overweight/obesity may have an impact on salivary biomarkers of mucosal immunity and sympathetic activation in children, however further research with regards to optimal intensity, duration and modality need to be assessed in the pre-pubescent population.Physical activity, obesity, immunity, neuro-endocrine, children, salivary biomarkers, sympathetic activation. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.

Thesis (PhD (Sport Science))—University of Stellenbosch, 2008. / The purpose of this study was to examine the effects of two different types of movement programs on movement competence, self-esteem and resiliency in adolescent girls from a low-socio economic environment. A non-equivalentcontrol-group design was followed. A total of N=63 girls from similar socioeconomic environments between the ages of 13-14 participated in the study. The subjects were divided into three groups. The pre-tests and post-tests were administered to all groups. Four motor fitness/motor ability tests were selected to gather data about movement competence. The Self-Perception Profile for Children (Harter, 1985) was used to measure self-esteem and the Connor-Davidson Resilience Scale (Connor & Davidson, 2003) was used to measure resiliency. Only two of the groups received intervention programs. One group received 20 sessions in an expressive dance movement program called Biodanza and the other intervention group received 20 sessions in self-defence.

Thesis (PhD (SportPsych))--University of Stellenbosch, 2009. / There has been a greater awareness in the psychological aspects of sport over the past few decades, and in particular, how the psyches of the players affect their performance. The game of cricket has been no exception. Neuro-Linguistic Programming (NLP) has been used successfully in the business world, but very little research has been done in the sport milieu. The motivation for this research was two-fold. First, there was the need for a cricket team to be mentally prepared to play at their highest potential on provincial level; second, the researcher was curious about NLP techniques being successfully applied in sport. NLP is the study of human excellence. It describes human functioning, and focuses on experience and experimenting rather than prescription; it can focus on how to intervene, transform and improve human functioning. NLP uses modelling to identify particular skills in successful people. (They like to say: “If he can do it, then I can do it too”.) Neuro refers to the nervous system and how it processes particular codes in the body through the five senses. Linguistic refers to the use of language and how it gives meaning to the neural processes through communication and symbolic systems. Programming refers to how a person sequences his actions to achieve his goals.

Thesis (PhD (Sports Science))--Stellenbosch University, 2008. / There is general consensus that athletes, striving to compete and perform at the highest level, should optimally balance training and competition stress with adequate regeneration. Although a well-planned training programme is of utmost importance, the time between training sessions and competitions is critical for the modern-day athlete. It is suggested that athletes should apply a variety of recovery methods to enhance the regeneration process. Although team sport is a popular entity throughout the world, there is limited published research on the regeneration process in team athletes and recovery methods to enhance the regeneration process. The aim of this study was to develop a model that could serve as a guideline for the regeneration of team athletes within the South African context. Two phases were involved in the process of developing a model. Phase one involved a research of literature in order to assess which strategies can be implemented for athletic regeneration, and what information team athletes are given for regeneration. The second phase involved an investigation into the recovery strategies that are currently used for regeneration by elite South African team players during the competitive phase of the year. Research questions focused on the recovery methods used by players, the perceived importance of various recovery methods to the players, and the relationship between sport and level of participation in the use of recovery strategies. This study did not attempt to assess the knowledge of the players on recovery methods.

Thesis (PhD (Sport Science))--Stellenbosch University, 2008. / The purpose of this study was to determine the effectiveness of a 16-week multidimensional intervention programme on the speed and accuracy of decision making, declarative knowledge and visual skills of u/20 rugby players. Two intact groups of rugby academy players participated in this study. One academy group participated in the intervention programme, which included activities, including the statistical analysis of individual players, game analysis, tactical rugby discussions, rugby rule discussions and visual skills training. The other academy group served as the comparison group and completed both the pre- and post-tests. The results indicated significant improvements in the speed of tactical decision making by participants in both the experimental and the comparison groups. Both groups also indicated a significant deterioration in the accuracy of their decisions. Both groups achieved a significant improvement in their declarative knowledge of rugby rules, as well as in their visual skills. The similarity in the post-test scores of the two groups led to the conclusion that the intervention programme, as presented in this study, did not appear to make a significant impact on the players. Suggestions are made for the design of future intervention programmes to improve tactical decision making.

Thesis (PhD (Sport Science))—University of Stellenbosch, 2006. / Sport performance management has emerged as a specialization in sport science that is focused on providing the athlete and coach with optimal information about training programmes and the support services needed in order to pursue excellence. As a more professional approach to disability sport has grown with the international status of the Paralympics, sport performance management dealing specifically with athletes with disabilities requires development. The purpose of this study was to focus on documenting the delivery of sport science support for three cyclists with cerebral palsy training for the Athens Paralympics. A case study approach was taken in this research that provided sport science support to three cyclists. Documentation of the training experience of each cyclist over 18 months of training leading up to the Games, was accomplished by quantification of daily training as well as periodic laboratory testing. A comprehensive picture was drawn of training intensities, modalities and frequencies for each cyclist during each macro-cycle, with special attention to the following three variables. Power output and lactate Power output and VO2 max Peak and mean sprint power output (Wingate test) Two of the three cyclists perceived the support they received to have been critical to the success of their preparation. The investigator concluded that sport management has an important role to play in the development of disability sport at the elite level, and that a lot more hard training is possible for cyclists with cerebral palsy, than some coaches may have previously believed, especially in terms of intensity and duration.

Thesis (PhD (Sport Sc) (Sport Science))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The purpose of this study was to explore the knowledge of tennis tactics of a group of South African tennis coaches. A secondary purpose was to gather their perceptions about where they believe they learned about tactics. A mixed methodology approach was used. The first was a quantitative knowledge test administered to 37 coaches. The second was a qualitative semi-structured interview with five coaches. The results of the study showed that there was a significant difference in the choices of tactical options in 43 game scenarios between the less experienced and the more experienced coaches. No differences were found between coaches who were coaching at the top level compared to the lower levels. No differences were found between coaches who had been top tennis players and those who had not. The majority of the coaches in this study reported that they had learned tactics through trial and error. Problems facing the development of top level tennis coaches in South Africa are discussed in relation to their knowledge of tactics and the priorities for the development of mass participation supported by national sport policy. / AFRIKAANSE OPSOMMING: Die hoofdoel van hierdie studie was om ʼn groep Suid-Afrikaanse tennisafrigters se kennis van tennistaktiek te ondersoek. ʼn Sekondêre doel was om uit te vind waar die afrigters glo hulle sodanige kennis opgedoen het. Die navorsingsbenadering het uit gemengde metodologieë bestaan. Die eerste was ʼn kwantitatiewe kennistoets wat onder 37 afrigters afgeneem is. Die tweede was ʼn kwalitatiewe semigestruktureerde onderhoud met vyf afrigters. Die resultate van die studie dui daarop dat die minder ervare en meer ervare afrigters geen beduidende verskil getoon het in hul taktiese keuses in 43 wedstrydscenario’s nie. Geen verskil is opgemerk tussen afrigters op die topvlak en dié op laer vlakke nie. Boonop was daar geen verskil tussen afrigters wat eens topspelers was en diegene wat nié was nie. Volgens die meeste van die afrigters in die studie het hulle hul kennis van tennistaktiek deur die metode van leer en probeer opgedoen. Die studie bespreek die uitdagings in die ontwikkeling van topvlaktennisafrigters in Suid-Afrika wat betref hul kennis van taktiek en die prioriteite vir die bevordering van massadeelname ingevolge nasionale sportbeleid.

Thesis (PhD (Sport Sc) (Sport Science))--University of Stellenbosch, 2011. / Please refer to full text to view abstract.

Thesis (PhD(Sport Sc))--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The purpose of this research was to gain insight into the sprinting of athletes with selected physical disabilities. The sprint performances of four Paralympic athletes (T43, T13, T37 and T38 classifications) were analysed in terms of variability in the biomechanics of their set position and in the kinematics of the initial acceleration phase and the maximal acceleration phase of their 100m sprints. The athletes also reported their perceptions about the potential of a rhythm training programme to influence their sprinting. A case study approach was used. Sprint kinematics were video-recorded four times over the training year. DartFish ProSuite software supported the digital tagging of anatomical landmarks and the calculation of the biomechanical features of the set position as well as the kinematics of each athlete. A subjective log was used to gather their perceptions about the rhythm training programme. There was variability in all aspects for all four Paralympic athletes. This should encourage coaches to help athletes find optimal kinematics in relation to their disability, rather than trying to coach them to a set template of an ideal form. Based on the kinematic data collected over all four test sessions, it appears that a coaching focus on stride length was the key to faster sprinting for this T43 (amputee) athlete. A coaching focus on stride frequency (once optimal stride length had been discovered) was the key for the T13 sprinter (visually impaired), and a coaching focus on stride frequency was the key to faster sprinting for both the T37 and T38 athletes (cerebral palsy). Although all of the athletes enjoyed the rhythm training programme, only the least experienced athlete (T38) reported that he would like to continue with this form of training. / AFRIKAANSE OPSOMMING: Die doel van hierdie navorsing was om insig rakende die naellooptegnieke van atlete met geselekteerde fisiese gestremdhede te verky. Die naellooptegnieke van vier Paralimpiese atlete (T43, T13, T37 en T38 klassifikasies) is ontleed. Die ontleding is gedoen met betrekking tot die veranderlikheid in biomeganika tydens hul gereedheidsposisies in die wegspringblokke asook in die kinematika van die aanvanklike versnellingsfase en die maksimale versnellingsfase gedurende hul 100m naelloopitems. Die atlete het ook hul persepsies rakende ’n ritmiese oefenprogram wat potensieël hul naellope kon beïnvloed gerapporteer. ’n Gevallestudiebenadering is gebruik. Beeldmateriaal van naelloopkinematika is vier keer gedurende die oefenjaar vasgelê. “DartFish ProSuite” sagteware het die digitale kodering van anatomiese punte ondersteun asook die berekening van biomeganiese eienskappe gedurende die gereedheidsposisie en die kinematika van elke atlete gefasiliteer. Daar is op ’n subjektiewe basis boekgehou van die atlete se persepsies rakende die ritmiese oefenprogram. Daar was wisselvalligheid in alle aspekte met betrekking tot al vier Paralimpiese atlete. Dit behoort as aanmoeding vir afrigters te dien om atlete te help om optimale kinematika in verband met hul gestremdheid te vind, eerder as om die atlete volgens ’n vaste templaat of ideale vorm te probeer afrig. Volgens die kinematiese data wat oor die loop van al vier toetsingsessies ingesamel is blyk dit asof ’n afrigtingsfokus op treëlengte die sleutel tot vinniger naellope vir die T43- atleet (amputasie) was. ’n Afrigtingsfokus op treëfrekwensie (nadat optimale treëlengte bewerkstellig is) was die sleutel vir die T13-atleet (visueel gestremd) en ’n afrigtingsfokus op treëfrekwensie was die sleutel tot vinniger naellope vir beide die T37- en T38-atlete (serebrale gestremdheid). Alhoewel al die atlete die ritmiese oefenprogram geniet het, het slegs die mees onervare atleet (T38) aangedui dat hy met hierdie vorm van oefening sou wou aanhou.

Thesis (M Sport Sc (Sport Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The study investigated the exercise preferences of female university students participating in exercise modes presented at the local gymnasium and their expectations of the outcomes of such participation. Secondly, the study aimed to determine the most important reason for their participation and whether this was satisfied by their choice of exercise mode. A third aim was to determine other reasons that contributed to the selection of exercise environment and mode. The size of the research group of the pilot study was 210 (n=210). For the final longitudinal study, over a period of three years, it was 985 (N=985). The study population was selected on a basis of convenient sampling, availability and interest among young female gymnasium members, (aged 18 to 27 years). Their participation was voluntary. Original questionnaires were constructed for the purpose of the study to provide general demographic and physical characteristic information of the participants, their exercise preference and choice of exercise mode, reasons for participation in particular exercise modes, time spent on physical activity, frequency of attendance of exercise sessions, exercise motivators, barriers to exercise, medication and supplementation prevalence, health problems and smoking. The questionnaire was completed in a five to 10 minute time slot before the commencement of exercise classes at the gymnasium. Information required on the questionnaire was verbally explained to the participants during the initial few minutes of data capturing. Guidance was given for each section of the questionnaire during the five to 10 minute period allocated for completion. Data was captured on Microsoft Excel spreadsheets and the analysis was performed using Statistica for Windows (Statsoft SA-2008). Descriptive statistics were used to analyse and present the data. The results of the study indicated that most (34.4%) young female students who regularly attended group exercise sessions at the gymnasium preferred participating in the exercise modality punchline (a boxing aerobic modality), with the aim of losing weight (45%) and improving their general fitness (24%). / AFRIKAANSE OPSOMMING: Die doel van die studie was om die oefenvoorkeure en oefenverwagtinge van jong damestudente wat gereeld by die plaaslike universiteitgimnasium oefen, vas te stel. Tweedens wou die studie die belangrikste redes vir deelname bepaal, en of hierdie verwagting gerealiseer het met die keuse van oefenmodaliteite in hierdie oefenomgewing. 'n Derde doel was om vas te stel watter ander redes 'n bydrae sou maak tot die keuse van 'n oefenomgewing en oefenmodaliteite. Die navorsingspopulasiegroep was jong dames in 'n universiteitsomgewing. Tydens die verkennende studie was die getal kandidate 210 (n=210). Vir die finale longitudinale studie, oor ’n tydperk van 3 jaar, was dit 985 (N=985). Die jong dames by die spesifieke universiteitgimnasium is geselekteer op grond van beskikbaarheid en belangstelling in die navorsing en was tussen die ouderdom van 18 en 27 jaar. Hul deelname was vrywillig. 'n Vraelys is spesiaal vir hierdie navorsing opgestel. Die vraelys het inligting ingewin oor algemene demografiese aspekte en fisieke kenmerke van die deelnemers, oefenvoorkeure en verwagtings van oefenmodaliteite, redes vir die seleksie en deelname in oefenmodaliteite, tyd bestee aan oefening, frekwensie van deelname, motiveerders vir oefening, beperkende faktore ten opsigte van gereelde deelname aan fisieke aktiwiteit, medikasie en supplementasie gebruik, gesondheidsprobleme en rook. Die vraelyste is voltooi in die eerste vyf tot 10 minute van oefenklasse, voor die aanvang van die gereelde gimnasiumprogram. Inligting op die vraelys is verbaal aan die teikengroep verduidelik in die eerste paar minute van elke klas. Tydens hierdie tydperk is gereeld inligting oor elke vraag verskaf vir kontrole en akkuraatheid van voltooiing van die vraelys. Data oor die veranderlikes is in die rekenaarprogram Microsoft Excel gekodeer en die statistiese ontleding is deur middel van Statistica vir Windows (Statsoft SA 2008) gedoen. Beskrywende data is gebruik om die resultate te ontleed en aan te bied.