Aandagtekort-hiperaktiwiteitsversteuring (ATHV) is een van die deeglikste nagevorste opvoedkundig-sielkundige versteurings. Dit is ook een van die versteurings waarvan die voorkoms drasties vermeerder het oor die laaste drie dekades, met ʼn voorkoms by skoolkinders van 3 tot 17%. Dit kom ook by volwassenes voor. Stimulantmedikasie word algemeen in die behandeling van ATHV voorgeskryf. Ander algemene behandelingsmodaliteite sluit onder andere gedragsterapie, dieët aanpassings en arbeidsterapie in. Oefening as hulpmiddel in die bestuur van ATHV, word goed in die literatuur beskryf, maar word ten spyte hiervan nie algemeen voorgeskryf in die behandeling van ATHV nie. Die primêre doel van die studie was om die rol wat die biokinetikus as oefenkundige te speel het in die bestuur van ATHV, te ondersoek. Die hipotese was dat ATHV-pasiënte wat deelneem aan ʼn oefenprogram onder leiding van ʼn biokinetikus, ʼn verbetering sal toon in akademiese prestasie en gedrag. Die verband tussen ATHV-simptome, aërobiese fiksheid, soepelheid, liggaamsamestelling en balans is ook ondersoek. Deur middel van ʼn meervuldige gevallestudieontwerp is die rol van die biokinetikus in dié verband ondersoek. ʼn Gemengde benadering, met kwantitatiewe sowel as kwalitatiewe elemente, is gebruik ten einde ʼn ryk en omvattende studie te kon doen. Riglyne vir die assessering van ATHV-pasiënte, asook beste oefenpraktyke, is uit die literatuur afgelei. Vyf deelnemers het vir ʼn tydperk van twee tot drie skoolkwartale aan die studie deelgeneem. Die intervensie het bestaan uit ʼn oefenprogram van ongeveer 30 minute per dag, vyf dae per week. Al die deelnemers is vooraf, asook tydens en na die studie getoets aan die hand van die volgende: Liggaamsamestelling, aërobiese fiksheid, soepelheid en balans. Onderhoude met onderwyseresse en ouers, skoolrapporte en vraelyste is verder gebruik om inligting in te samel. Deelnemers het ook narratiewe verslae gelewer oor die belewenis van hulle deelname. Die resultate van hierdie studie het die hipotese ondersteun. Die deelnemers het verbeterings ten opsigte van akademiese prestasie en gedrag getoon. Hulle aërobiese kapasiteit, liggaamsamestelling, soepelheid en balans het ook verbeter en die verband tussen die onderskeie parameters en die ATHVsimptome van elke deelnemer, is aangetoon en individueel bespreek. ʼn Gedeelde sorgooreenkomsmodel is ontwikkel om die rol van die biokinetikus duidelik aan te dui. ʼn Evaluasieprotokol vir gebruik deur biokinetici is ontwikkel en riglyne vir programontwerp vir die ATHV-pasiënt is saamgestel. Die gevolgtrekking van die studie is dat die biokinetikus ʼn besliste rol te speel het in die bestuur van ATHV. / Thesis (PhD)--University of Pretoria, 2013. / gm2014 / Biokinetics, Sport and Leisure Sciences / unrestricted

The female athlete triad (FAT or the TRIAD) is a complex syndrome arising from associations among the trio of energy availability (EA), menstrual function (MF) and bone mineral density (BMD) along their respective continuums from health to disease state. It has been recognized that women whose energy intake (EI) does not meet the energy requirements for physiological functions subsequent to participation in exercise and physical activity could have low EA. In the TRIAD, low EA, an initiator in menstrual dysfunction (MD) and concomitant hypoestrogenism, indirectly results in low BMD. Therefore, the purpose of this study was to: (i) establish the status of EA, MF and BMD among elite Kenyan female athletes and non-athletes, (ii) explore associations between EA and MF in elite Kenyan female athletes and non-athletes, (iii) determine the relationships of EA and MF to BMD in elite Kenyan female athletes and non-athletes, and (iv) to determine the profile of the female athlete triad in elite Kenyan distance athletes and in non-athletes. Measurements of EA, MF and BMD were undertaken in 39 female participants (Middle distance athletes =12, Long distance athletes=13, Non-athletes=14). Energy intake minus exercise energy expenditure (EEE) and the remnant normalized to fat free mass (FFM) determined EA. Energy availability was determined through weight of all food and liquid consumed over three consecutive days. Exercise energy expenditure was determined after isolating and deducting energy expended in exercise or physical activity above lifestyle level from the total energy expenditure output as measured by Actigraph GT3X+. Fat free mass and BMD were assessed using dual energy x-ray absorptiometry (DXA). A nine-month daily temperature-menstrual diary was used to evaluate menstrual status. In addition, since psychological eating behaviour practice (EBP) contributes to low EA, the Eating Disorder Examination Questionnaire (EDE-Q) was used to determine presence of such practice among the participants and their relationship to EA. Overall, EA below 45 kcal.kgFFM-1.d-1 was found in 61.53% of the participants (athletes=28.07±11.45kcal.kgFFM-1.d-1, non-athletes=56.97±21.38kcal.kgFMM-1.d-1). The ANOVA showed that there was a significant difference (p<0.001) in EA among the long and middle distance runners and non-athletes; and the Tukey‘s HSD revealed that the source of the difference were the non-athletes. Results of the EDE-Q showed almost negligible presence of psychopathological eating behaviour practice among the Kenyan participants. None of the TRIAD components showed significant relationship with EBP. Results of MF showed that whereas none of the athletes presented with amenorrhea, oligomenorrhea was present among 40% athletes and 14.3% non-athletes, and amenorrhea among 14.3% non-athletes. However, there was no significant difference between athletes and non-athletes in MF. Low BMD was seen in 76% of the athletes and among 86% of the non-athletes. The analysis did not show significant difference in BMD Z-scores between athletes and non-athletes. The analysis did not show any significant association between EA and MF among the participants. The only significant relation of EA to any BMD dimension measured was between EA and total BMD in the long distance runners (r=0.560; p=.046). Significant relationship (rho=0.497; p=.001) was found between MF and BMD Z-scores among the athletes with middle distance highlighting the relationship further (rho=0.632; p=.027). Overall, the binary logistic regression revealed that MF did not predict BMD (OR=4.07, 95% CI, 0.8-20.7, p=.091). Overall, 10% of the participants (athletes=4, long distance athletes =3, middle distance athletes=1, non-athletes=0) showed simultaneous presence of all three components of the TRIAD. The independent sample t-test showed a significant difference (t=5.860; p=<.001) in the prevalence of the TRIAD between athletes and non-athletes. / PhD (Human Movement Science), North-West University, Potchefstroom Campus, 2014

The female athlete triad (FAT or the TRIAD) is a complex syndrome arising from associations among the trio of energy availability (EA), menstrual function (MF) and bone mineral density (BMD) along their respective continuums from health to disease state. It has been recognized that women whose energy intake (EI) does not meet the energy requirements for physiological functions subsequent to participation in exercise and physical activity could have low EA. In the TRIAD, low EA, an initiator in menstrual dysfunction (MD) and concomitant hypoestrogenism, indirectly results in low BMD. Therefore, the purpose of this study was to: (i) establish the status of EA, MF and BMD among elite Kenyan female athletes and non-athletes, (ii) explore associations between EA and MF in elite Kenyan female athletes and non-athletes, (iii) determine the relationships of EA and MF to BMD in elite Kenyan female athletes and non-athletes, and (iv) to determine the profile of the female athlete triad in elite Kenyan distance athletes and in non-athletes. Measurements of EA, MF and BMD were undertaken in 39 female participants (Middle distance athletes =12, Long distance athletes=13, Non-athletes=14). Energy intake minus exercise energy expenditure (EEE) and the remnant normalized to fat free mass (FFM) determined EA. Energy availability was determined through weight of all food and liquid consumed over three consecutive days. Exercise energy expenditure was determined after isolating and deducting energy expended in exercise or physical activity above lifestyle level from the total energy expenditure output as measured by Actigraph GT3X+. Fat free mass and BMD were assessed using dual energy x-ray absorptiometry (DXA). A nine-month daily temperature-menstrual diary was used to evaluate menstrual status. In addition, since psychological eating behaviour practice (EBP) contributes to low EA, the Eating Disorder Examination Questionnaire (EDE-Q) was used to determine presence of such practice among the participants and their relationship to EA. Overall, EA below 45 kcal.kgFFM-1.d-1 was found in 61.53% of the participants (athletes=28.07±11.45kcal.kgFFM-1.d-1, non-athletes=56.97±21.38kcal.kgFMM-1.d-1). The ANOVA showed that there was a significant difference (p<0.001) in EA among the long and middle distance runners and non-athletes; and the Tukey‘s HSD revealed that the source of the difference were the non-athletes. Results of the EDE-Q showed almost negligible presence of psychopathological eating behaviour practice among the Kenyan participants. None of the TRIAD components showed significant relationship with EBP. Results of MF showed that whereas none of the athletes presented with amenorrhea, oligomenorrhea was present among 40% athletes and 14.3% non-athletes, and amenorrhea among 14.3% non-athletes. However, there was no significant difference between athletes and non-athletes in MF. Low BMD was seen in 76% of the athletes and among 86% of the non-athletes. The analysis did not show significant difference in BMD Z-scores between athletes and non-athletes. The analysis did not show any significant association between EA and MF among the participants. The only significant relation of EA to any BMD dimension measured was between EA and total BMD in the long distance runners (r=0.560; p=.046). Significant relationship (rho=0.497; p=.001) was found between MF and BMD Z-scores among the athletes with middle distance highlighting the relationship further (rho=0.632; p=.027). Overall, the binary logistic regression revealed that MF did not predict BMD (OR=4.07, 95% CI, 0.8-20.7, p=.091). Overall, 10% of the participants (athletes=4, long distance athletes =3, middle distance athletes=1, non-athletes=0) showed simultaneous presence of all three components of the TRIAD. The independent sample t-test showed a significant difference (t=5.860; p=<.001) in the prevalence of the TRIAD between athletes and non-athletes. / PhD (Human Movement Science), North-West University, Potchefstroom Campus, 2014

This study examined the energy dependence of cancer cells. Glucose was found to be their main energy source. It seems possible to use this dependence to advantage in the fight against cancer. A novel experiment to reduce the blood glucose supply and utilisation was proposed. It entailed caloric restriction, suppression of glucose secretion by the liver as well as suppression of stress hormones (which elevates glucose levels). This minimises the blood glucose value. As a last step, anti-insulin is provided to inhibit cancer cells to utilise the glucose. The cancer cells are thus deprived of their main energy source. This should lead to a reduction or elimination of tumours and will aid in preventing their development. Although feasible, this method turned out to be too expensive to perform the necessary clinical trials to prove the hypothesis. Next, the focus shifted to cancer prevention. The human energy system was analysed with the goal to reduce the circulating glucose level. The main focus here was metabolised CHO energy consumption. A previously proposed unit – the Equivalent Teaspoon Sugar, or ets , was used to quantify energy with. It was shown that cancer risk increases significantly when the recommended ets consumption per day is exceeded. Furthermore, it was shown that including fibre in a meal reduces the ets value of the meal. One gram of fibre leads to a reduction of around 0.6 ets . The link between exercise, stress, fibre, their resulting blood glucose levels and cancer were quantified in terms of ets . Exercise expends ets , while stress causes the liver to secrete more ets . Experimental data was analysed to confirm the relationships. In conclusion an equation was formulated to describe the combined effect of all these elements on the energy system. One’s total daily ets consumption can be obtained from the equation, and it was linked to one’s cancer risk. Adapting a lifestyle that ensures the correct daily ets intake will lead to a significant reduction in cancer risk. This study proved that cancer cells are very dependent on sugar and a restriction of this energy source forces them into regression. Using this knowledge to advantage may help in the combat one of the biggest killers of our time – cancer. / Thesis (Ph.D. (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2012

This study examined the energy dependence of cancer cells. Glucose was found to be their main energy source. It seems possible to use this dependence to advantage in the fight against cancer. A novel experiment to reduce the blood glucose supply and utilisation was proposed. It entailed caloric restriction, suppression of glucose secretion by the liver as well as suppression of stress hormones (which elevates glucose levels). This minimises the blood glucose value. As a last step, anti-insulin is provided to inhibit cancer cells to utilise the glucose. The cancer cells are thus deprived of their main energy source. This should lead to a reduction or elimination of tumours and will aid in preventing their development. Although feasible, this method turned out to be too expensive to perform the necessary clinical trials to prove the hypothesis. Next, the focus shifted to cancer prevention. The human energy system was analysed with the goal to reduce the circulating glucose level. The main focus here was metabolised CHO energy consumption. A previously proposed unit – the Equivalent Teaspoon Sugar, or ets , was used to quantify energy with. It was shown that cancer risk increases significantly when the recommended ets consumption per day is exceeded. Furthermore, it was shown that including fibre in a meal reduces the ets value of the meal. One gram of fibre leads to a reduction of around 0.6 ets . The link between exercise, stress, fibre, their resulting blood glucose levels and cancer were quantified in terms of ets . Exercise expends ets , while stress causes the liver to secrete more ets . Experimental data was analysed to confirm the relationships. In conclusion an equation was formulated to describe the combined effect of all these elements on the energy system. One’s total daily ets consumption can be obtained from the equation, and it was linked to one’s cancer risk. Adapting a lifestyle that ensures the correct daily ets intake will lead to a significant reduction in cancer risk. This study proved that cancer cells are very dependent on sugar and a restriction of this energy source forces them into regression. Using this knowledge to advantage may help in the combat one of the biggest killers of our time – cancer. / Thesis (Ph.D. (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2012

Afrikaans text / Die doel van hierdie studie was om te bepaal wat die invloed van motoriese oefening op die leervermoë van die leerder in die grondslagfase is. Vyf en twintig leerders is ewekansig verdeel in `n eksperimentele en kontrole groep. Oor `n tydperk van vyf weke, voor die aanvang van elke leerafdeling, het die eksperimentele groep, saam met die onderwyseres, klaskamer gebaseerde motoriese oefeninge verrig terwyl die kontrole groep geen intervensie ontvang het nie. Die Copeland’s checklist for Attention Deficit Disorder vraelys is as voor- en natoets gebruik. Na die afloop van die empiriese ondersoek het die eksperimentele groep `n verbetering getoon in onoplettendheid/afleibaarheid, impulsiwiteit, ooraktiwiteit/hiperaktiwiteit, onderaktiwiteit en aandagvermoë, terwyl die kontrole groep oor dieselfde tydperk verswak het of onveranderd gebly het. Die veranderinge was egter nie statisties betekenisvol (p≤0.05) nie. Hierdie resultaat dui slegs op „n tedens dat motoriese oefening 'n positiewe effek op die leerders se leervermoë in die grondslagfase het. / Educational Studies / M. Ed. (Educational Studies)

Afrikaans text / Die doel van hierdie studie was om te bepaal wat die invloed van motoriese oefening op die leervermoë van die leerder in die grondslagfase is. Vyf en twintig leerders is ewekansig verdeel in `n eksperimentele en kontrole groep. Oor `n tydperk van vyf weke, voor die aanvang van elke leerafdeling, het die eksperimentele groep, saam met die onderwyseres, klaskamer gebaseerde motoriese oefeninge verrig terwyl die kontrole groep geen intervensie ontvang het nie. Die Copeland’s checklist for Attention Deficit Disorder vraelys is as voor- en natoets gebruik. Na die afloop van die empiriese ondersoek het die eksperimentele groep `n verbetering getoon in onoplettendheid/afleibaarheid, impulsiwiteit, ooraktiwiteit/hiperaktiwiteit, onderaktiwiteit en aandagvermoë, terwyl die kontrole groep oor dieselfde tydperk verswak het of onveranderd gebly het. Die veranderinge was egter nie statisties betekenisvol (p≤0.05) nie. Hierdie resultaat dui slegs op „n tedens dat motoriese oefening 'n positiewe effek op die leerders se leervermoë in die grondslagfase het. / Educational Studies / M. Ed. (Educational Studies)

Low back pain has become one of the most influential musculoskeletal diseases of modern society. It is one of most expensive diseases in terms of medical costs and increased worker absenteeism, which can lead to permanent disability and places strain on the economy as a whole. Pain has been recognised as a disease in itself, which has certain consequences when it becomes chronic. Many kinds of treatment options exist with varying degrees of success. The question is thus which treatment option is the most favourable and cost-effective. Conservative treatment is the most recommended form of treatment when no serious underlying diseases are present. Exercise has been shown to be very effective in the treatment of chronic low back pain but there are still questions regarding the use of exercise therapy. The predetermined goal of the study was to ascertain whether an aggressiveprogressive exercise programme, and specifically what kind of exercises, would be more effective in the treatment of chronic low back pain. This was achieved through a number of steps, which included an extensive literature review, the identification of an appropriate test battery with related minimum physical requirements and cut scores, subject recruitment and screening of subjects, the implementation of the intervention and the subsequent re-testing of the subjects. Once the data was completed, the next step was to make use of two case studies to assist in illustrating the effectiveness of individual patients compared to the sample as a whole. These case studies were of patients who completed the entire programme but one took longer to complete the programme. This assists in illustrating the value of maintaining exercise protocol. The results from the present study are extremely positive. The two case studies provided a glimpse of the potential value that could be added through the implementation of more aggressive-progressive exercise interventions in the treatment of chronic low back pain. The final product will greatly assist exercise therapists concerned with the treatment of chronic low back pain along with cognitive-behavioural techniques. Hopefully this study will provide insight into managing chronic low back pain in South Africa from an exercise standpoint. Secondly the study will provide practical techniques to implement in an era in which economic difficulties are rife.AFRIKAANS: Laerugpyn het een van die invloedrykste muskuloskeletale siektes van die moderne samelewing geword. Dit is een van die duurste siektes in terme van mediese koste en verhoogde siekverlof deur werkers, wat kan lei tot permanente ongeskiktheid en ’n verhoogde las plaas op die ekonomie as ’n geheel. Pyn word erken as ’n siekte op sy eie wat sekere gevolge het wanneer dit chronies begin raak. Verskeie soorte behandelingsopsies is beskikbaar met variërende grade van sukses. Die vraag is dus watter behandelingsopsie is die bruikbaarste en koste-doeltreffendste. Konserwatiewe behandeling is die mees aanbevole metode van behandeling wanneer daar geen ernstige onderliggende siektetoestande teenwoordig is nie. Dit is reeds bewys dat oefening baie doeltreffend is in die behandeling van chroniese laerugpyn. Daar bestaan egter steeds vrae rondom die gebruik van oefening as terapie.Die vooropgestelde doelwit van die studie was om te bepaal of ’n aggressiewe-progressiewe inoefeningsprogram doeltreffend sal wees in die behandeling van chroniese laerugpyn, en meer spesifiek watter tipe oefening die doeltreffendste sal wees. Die navorsing het bestaan uit ’n paar stappe wat ingesluit het ’n intensiewe literatuursoektog, die identifisering van ’n gepaste toetsbattery met verwante minimum fisieke vereistes en afsnytellings, die verkryging en evaluering van proefpersone, die implementering van die intervensieprogram en die daaropvolgende hertoetsing van die proefpersone.Nadat die invordering van die data en die gepaardgaande analise van die data voltooi is, was die volgende stap om gebruik te maak van twee gevallestudies ten einde die doeltreffendheid van die intervensieprogram vir individuele proefpersone te ilustreer deur dit te vergelyk met die groep as ’n geheel. Die twee gevallestudies was van proefpersone wat die intervensieprogram volledig voltooi het, alhoewel die een proefpersoon langer geneem het om die intervensieprogram te voltooi. Dit help om die navolgingswaarde van ’n inoefeningsprotokol te illustreer. Die resultate van die huidige studie is uiters positief. Die twee gevallestudies gee ’n mate van insig wat betref die potensiële waarde wat verkry kan word deur die implementering van ’n meer aggressiewe-progressiewe inoefeningsintervensie vir die behandeling van chroniese lae rugpyn. Die finale produk sal die nodige ondersteuning aan oefeningsterapeute bied wat onseker is oor die behandeling van chroniese laerugpyn deur middel van aggressiewe-progressiewe inoefeningsintervensies en kognitiewe gedragstegnieke. Hierdie studie sal dus die begrip en insig van die behandeling van chroniese laerugpyn in Suid-Afrika verhoog vanuit ’n oefeningsuitgangspunt. Tweedens sal die studie die gebruik van praktiese oefentegnieke aanmoedig in ’n era waarin ekonomiese tye moeilik is. / Thesis (DPhil)--University of Pretoria, 2011. / Biokinetics, Sport and Leisure Sciences / unrestricted

Preface - Biotechnology is generally accepted to be the next economical wave of the future. In order to attain the many benefits associated with this growing industry simulation modelling techniques have to be implemented successfully. One of the simulations that ne' ed to be performed is that of the human energy system. Pharmaceutical companies are currently pouring vast amounts of capital into research regarding simulation of bodily processes. Their aim is to develop cures, treatments, medication, etc. for major diseases. These diseases include epidemics like diabetes, cancer, cardiovascular diseases, obesity, stress, hypertension, etc. One of the most important driving forces behind these diseases is poor blood sugar control. The blood glucose system is one of the major subsystems of the complete human energy system. In this study a simulation model and procedure for simulating blood glucose response due to various external influences on the human body is presented. The study is presented in two parts. The first is the development of a novel concept for quantifying glucose energy flow into, within and out of the human energy system. The new quantification unit is called ets (equivalent teaspoons sugar). The second part of the study is the implementation of the ets concept in order to develop the simulation model. Development of the ets concept - In the first part of the study the ets concept, used for predicting glycaemic response, is developed and presented. The two current methods for predicting glycaemic response due to ingestion of food are discussed, namely carbohydrate counting and the glycaemic index. Furthermore, it is shown that it is currently incorrectly assumed that 100% of the chemical energy contained in food is available to the human energy system after consumption. The ets concept is derived to provide a better measure of available energy from food. In order to verify the ets concept, two links with ets are investigated. These are the links with insulin response prediction as well as with endurance energy expenditure. It is shown that with both these links linear relationships provide a good approximation of empirical data. It is also shown that individualised characterisation of different people is only dependent on a single measurable variable for each link. Lastly, two novel applications of the ets concept are considered. The first is a new method to use the ets values associated with food and energy expenditure in order to calculate both short-acting and long-acting insulin dosages for Type 1 diabetics. The second application entails a new quantification method for describing the effects of stress and illness in terms of ets. Development of the blood glucose simulation model - The second part of the study presents a literature study regarding human physiology, the development for the blood glucose simulation model as well as a verification study of the simulation model. Firstly, a brief overview is given for the need and motivation behind simulation is given. A discussion on the implementation of the techniques for construction of the model is also shown. The procedure for solving the model is then outlined. During the literature study regarding human physiology two detailed schematic layouts are presented and discussed. The first layout involves the complex flow pathways of energy through the human energy system. The second layout presents a detailed discussion on the control system involved with the glucose energy pathway. Following the literature review the model for predicting glycaemic response is proposed. The design of the component models used for the simulations of the internal processes are developed in detail as well as the control strategies implemented for the control system of the simulation model. Lastly, the simulation model is applied for glycaemic response prediction of actual test subjects and the quality of the predictions are evaluated. The verification of the model and the procedure is performed by comparing simulated results to measured data. Two evaluations were considered, namely long-term and short-term trials. The quality of both are determined according to certain evaluation criteria and it is found that the model is more than 70% accurate for long-term simulations and more than 80% accurate for short-term simulations. Conclusion - In conclusion, it is shown that simplified simulation of the human energy system is not only possible but also relatively accurate. However, in order to accomplish the simulations a simple quantification method is required and this is provided by the ets concept developed in the first part of this study. Some recommendations are also made for future research regarding both the ets concept and the simulation model. Finally, as an initial endeavour the simulation model and the ets concept proposed in this study may provide the necessary edge for groundbreaking biotechnological discoveries. / PhD (Mechanical Engineering) North-West University, Potchefstroom Campus, 2003

Preface - Biotechnology is generally accepted to be the next economical wave of the future. In order to attain the many benefits associated with this growing industry simulation modelling techniques have to be implemented successfully. One of the simulations that ne' ed to be performed is that of the human energy system. Pharmaceutical companies are currently pouring vast amounts of capital into research regarding simulation of bodily processes. Their aim is to develop cures, treatments, medication, etc. for major diseases. These diseases include epidemics like diabetes, cancer, cardiovascular diseases, obesity, stress, hypertension, etc. One of the most important driving forces behind these diseases is poor blood sugar control. The blood glucose system is one of the major subsystems of the complete human energy system. In this study a simulation model and procedure for simulating blood glucose response due to various external influences on the human body is presented. The study is presented in two parts. The first is the development of a novel concept for quantifying glucose energy flow into, within and out of the human energy system. The new quantification unit is called ets (equivalent teaspoons sugar). The second part of the study is the implementation of the ets concept in order to develop the simulation model. Development of the ets concept - In the first part of the study the ets concept, used for predicting glycaemic response, is developed and presented. The two current methods for predicting glycaemic response due to ingestion of food are discussed, namely carbohydrate counting and the glycaemic index. Furthermore, it is shown that it is currently incorrectly assumed that 100% of the chemical energy contained in food is available to the human energy system after consumption. The ets concept is derived to provide a better measure of available energy from food. In order to verify the ets concept, two links with ets are investigated. These are the links with insulin response prediction as well as with endurance energy expenditure. It is shown that with both these links linear relationships provide a good approximation of empirical data. It is also shown that individualised characterisation of different people is only dependent on a single measurable variable for each link. Lastly, two novel applications of the ets concept are considered. The first is a new method to use the ets values associated with food and energy expenditure in order to calculate both short-acting and long-acting insulin dosages for Type 1 diabetics. The second application entails a new quantification method for describing the effects of stress and illness in terms of ets. Development of the blood glucose simulation model - The second part of the study presents a literature study regarding human physiology, the development for the blood glucose simulation model as well as a verification study of the simulation model. Firstly, a brief overview is given for the need and motivation behind simulation is given. A discussion on the implementation of the techniques for construction of the model is also shown. The procedure for solving the model is then outlined. During the literature study regarding human physiology two detailed schematic layouts are presented and discussed. The first layout involves the complex flow pathways of energy through the human energy system. The second layout presents a detailed discussion on the control system involved with the glucose energy pathway. Following the literature review the model for predicting glycaemic response is proposed. The design of the component models used for the simulations of the internal processes are developed in detail as well as the control strategies implemented for the control system of the simulation model. Lastly, the simulation model is applied for glycaemic response prediction of actual test subjects and the quality of the predictions are evaluated. The verification of the model and the procedure is performed by comparing simulated results to measured data. Two evaluations were considered, namely long-term and short-term trials. The quality of both are determined according to certain evaluation criteria and it is found that the model is more than 70% accurate for long-term simulations and more than 80% accurate for short-term simulations. Conclusion - In conclusion, it is shown that simplified simulation of the human energy system is not only possible but also relatively accurate. However, in order to accomplish the simulations a simple quantification method is required and this is provided by the ets concept developed in the first part of this study. Some recommendations are also made for future research regarding both the ets concept and the simulation model. Finally, as an initial endeavour the simulation model and the ets concept proposed in this study may provide the necessary edge for groundbreaking biotechnological discoveries. / PhD (Mechanical Engineering) North-West University, Potchefstroom Campus, 2003