Bone mineral density of female long distance runners in Nelson Mandela Bay
- Authors: Meier, Catherine Anne
- Date: 2018
- Subjects: Running -- Physiological aspects , Marathon running -- South Africa -- Nelson Mandela Bay Municipality Bones -- Metabolism Mineral metabolism Running -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/22946 , vital:30153
- Description: Long distance running may present positive and negative effects on the bone mineral density (BMD) of such participants. The advantage of high impact loads placed on the body of these runners may be neutralised or reversed, as too high a load may cause a decreased BMD. Furthermore, competitive female runners are generally considered to be leaner than their peers due to the nature of the sport. Therefore, it is expected that the majority of these runners would have a low body fat percentage (BF%) and body mass index (BMI) which may negatively affect the BMD, resulting in impaired bone quality. Due to the general inaccessibility of BMD assessments because of the cost involved, the incidence of risk for lowered BMD among long distance runners and particularly female runners are not readily known. The primary aim of the present study was therefore to determine the BMD rating and its association with body composition (BF% and BMI) and other selected factors among female long distance runners in Nelson Mandela Bay (NMB). The study utilized a quantitative approach and was exploratory, descriptive and non-experimental in nature. Non-probability, convenience sampling was implemented. A total of 40 female long distance runners between the age of 25 and 68 years (with a mean age of 43.6 ± 9.67 years) who have completed at least two marathon events were included in the study. The study utilized a questionnaire to collect demographic and other relevant information from the participants; a stadiometer and an electronic scale to measure height and weight and ultimately calculate BMI; and a bone densitometer with Dual-Energy X-ray Absorptiometry (DXA) (Hologic Discovery W) to determine the various BMD variables required as well as the BF%. Three densitometry scans were performed by a qualified radiographer which presented four analyses namely that of the relevant BMD variables for the hip, lumbar spine and total body, respectively, as well as of the BF% for the total body. The results of the study in respect of the overall BMD profile of the female long distance runners was considered to be normal except for the lumbar spine, found to be osteopenic when considering the mean T-score for this region of those 50 years and older. Overall the participants had an ‘average’ BF% (26.71 ± 6.33%) classification according to the ACSM classification rating system and were classified as ‘normal’ (22.80 ± 2.58 kg/m²) in respect of the BMI category rating. Significant correlations (r ≥ 0.312) were found between BMI and BMD related Z-scores for the hip, lumbar spine and total body, respectively. When considering the effect of selected variables on the various BMD variables, BF% and BMI, respectively, the following significant (p < .05; d > 0.2) results were found: (1) BMD (one or more rating and or Z-score) was positively influenced (had higher ratings) in runners who were overweight, consumed alcoholic beverages of five or less per week and who ran less than 51 km/week, respectively; (2) BMD (one or more rating and or Z-score) was negatively influenced (had lower ratings) in runners who had more full-term pregnancies and among those who were menopausal, respectively; (3) BF% and BMI were both found to be lower in runners who: were not menopausal, competed in six or more ultra-marathon events, completed marathons in less than or equal to three hours and 50 minutes, had an incidence of breaking a bone due to a traumatic event, and engaged in an average weekly running distance of more than 50 km/week, respectively.
- Full Text:
- Date Issued: 2018
- Authors: Meier, Catherine Anne
- Date: 2018
- Subjects: Running -- Physiological aspects , Marathon running -- South Africa -- Nelson Mandela Bay Municipality Bones -- Metabolism Mineral metabolism Running -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/22946 , vital:30153
- Description: Long distance running may present positive and negative effects on the bone mineral density (BMD) of such participants. The advantage of high impact loads placed on the body of these runners may be neutralised or reversed, as too high a load may cause a decreased BMD. Furthermore, competitive female runners are generally considered to be leaner than their peers due to the nature of the sport. Therefore, it is expected that the majority of these runners would have a low body fat percentage (BF%) and body mass index (BMI) which may negatively affect the BMD, resulting in impaired bone quality. Due to the general inaccessibility of BMD assessments because of the cost involved, the incidence of risk for lowered BMD among long distance runners and particularly female runners are not readily known. The primary aim of the present study was therefore to determine the BMD rating and its association with body composition (BF% and BMI) and other selected factors among female long distance runners in Nelson Mandela Bay (NMB). The study utilized a quantitative approach and was exploratory, descriptive and non-experimental in nature. Non-probability, convenience sampling was implemented. A total of 40 female long distance runners between the age of 25 and 68 years (with a mean age of 43.6 ± 9.67 years) who have completed at least two marathon events were included in the study. The study utilized a questionnaire to collect demographic and other relevant information from the participants; a stadiometer and an electronic scale to measure height and weight and ultimately calculate BMI; and a bone densitometer with Dual-Energy X-ray Absorptiometry (DXA) (Hologic Discovery W) to determine the various BMD variables required as well as the BF%. Three densitometry scans were performed by a qualified radiographer which presented four analyses namely that of the relevant BMD variables for the hip, lumbar spine and total body, respectively, as well as of the BF% for the total body. The results of the study in respect of the overall BMD profile of the female long distance runners was considered to be normal except for the lumbar spine, found to be osteopenic when considering the mean T-score for this region of those 50 years and older. Overall the participants had an ‘average’ BF% (26.71 ± 6.33%) classification according to the ACSM classification rating system and were classified as ‘normal’ (22.80 ± 2.58 kg/m²) in respect of the BMI category rating. Significant correlations (r ≥ 0.312) were found between BMI and BMD related Z-scores for the hip, lumbar spine and total body, respectively. When considering the effect of selected variables on the various BMD variables, BF% and BMI, respectively, the following significant (p < .05; d > 0.2) results were found: (1) BMD (one or more rating and or Z-score) was positively influenced (had higher ratings) in runners who were overweight, consumed alcoholic beverages of five or less per week and who ran less than 51 km/week, respectively; (2) BMD (one or more rating and or Z-score) was negatively influenced (had lower ratings) in runners who had more full-term pregnancies and among those who were menopausal, respectively; (3) BF% and BMI were both found to be lower in runners who: were not menopausal, competed in six or more ultra-marathon events, completed marathons in less than or equal to three hours and 50 minutes, had an incidence of breaking a bone due to a traumatic event, and engaged in an average weekly running distance of more than 50 km/week, respectively.
- Full Text:
- Date Issued: 2018
An Internet of things model for field service automation
- Authors: Kapeso, Mando Mulabita
- Date: 2017
- Subjects: Internet of things Manufacturing processes -- Automation , Automation
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/18641 , vital:28698
- Description: Due to the competitive nature of the global economy, organisations are continuously seeking ways of cutting costs and increasing efficiency to gain a competitive advantage. Field service organisations that offer after sales support seek to gain a competitive advantage through downtime minimisation. Downtime is the time between service requests made by a customer or triggered by equipment failure and the completion of the service to rectify the problem by the field service team. Researchers have identified downtime as one of the key performance indicators for field service organisations. The lack of real-time access to information and inaccuracy of information are factors which contribute to the poor management of downtime. Various technology advancements have been adopted to address some of the challenges faced by field service organisations through automation. The emergence of an Internet of Things (IoT), has brought new enhancement possibilities to various industries, for instance, the manufacturing industry. The main research question that this study aims to address is “How can an Internet of Things be used to optimise field service automation?” The main research objective was to develop and evaluate a model for the optimisation of field services using an IoT’s features and technologies. The model aims at addressing challenges associated with the inaccuracy or/and lack of real-time access to information during downtime. The model developed is the theoretical artefact of the research methodology used in this study which is the Design Science Research Methodology (DSRM). The DSRM activities were adopted to fulfil the research objectives of this research. A literature review in the field services domain was conducted to establish the problems faced by field service organisations. Several interviews were held to verify the problems of FSM identified in literature and some potential solutions. During the design and development activity of the DSRM methodology, an IoT model for FSA was designed. The model consists of:The Four Layered Architecture; The Three Phase Data Flow Process; and Definition and descriptions of IoT-based elements and functions. The model was then used to drive the design, development, and evaluation of “proof of concept” prototype, the KapCha prototype. KapCha enables the optimisation of FSA using IoT techniques and features. The implementation of a sub-component of the KapCha system, in fulfilment of the research. The implementation of KapCha was applied to the context of a smart lighting environment in the case study. A two-phase evaluation was conducted to review both the theoretical model and the KapCha prototype. The model and KapCha prototype were evaluated using the Technical and Risk efficacy evaluation strategy from the Framework for Evaluation of Design Science (FEDS). The Technical Risk and Efficacy strategy made use of formative, artificial-summative and summative-naturalistic methods of evaluation. An artificial-summative evaluation was used to evaluate the design of the model. Iterative formative evaluations were conducted during the development of the KapCha. KapCha was then placed in a real-environment conditions and a summative-naturalistic evaluation was conducted. The summative-naturalistic evaluation was used to determine the performance of KapCha under real-world conditions to evaluate the extent it addresses FSA problems identified such as real-time communication and automated fault detection.
- Full Text:
- Date Issued: 2017
- Authors: Kapeso, Mando Mulabita
- Date: 2017
- Subjects: Internet of things Manufacturing processes -- Automation , Automation
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/18641 , vital:28698
- Description: Due to the competitive nature of the global economy, organisations are continuously seeking ways of cutting costs and increasing efficiency to gain a competitive advantage. Field service organisations that offer after sales support seek to gain a competitive advantage through downtime minimisation. Downtime is the time between service requests made by a customer or triggered by equipment failure and the completion of the service to rectify the problem by the field service team. Researchers have identified downtime as one of the key performance indicators for field service organisations. The lack of real-time access to information and inaccuracy of information are factors which contribute to the poor management of downtime. Various technology advancements have been adopted to address some of the challenges faced by field service organisations through automation. The emergence of an Internet of Things (IoT), has brought new enhancement possibilities to various industries, for instance, the manufacturing industry. The main research question that this study aims to address is “How can an Internet of Things be used to optimise field service automation?” The main research objective was to develop and evaluate a model for the optimisation of field services using an IoT’s features and technologies. The model aims at addressing challenges associated with the inaccuracy or/and lack of real-time access to information during downtime. The model developed is the theoretical artefact of the research methodology used in this study which is the Design Science Research Methodology (DSRM). The DSRM activities were adopted to fulfil the research objectives of this research. A literature review in the field services domain was conducted to establish the problems faced by field service organisations. Several interviews were held to verify the problems of FSM identified in literature and some potential solutions. During the design and development activity of the DSRM methodology, an IoT model for FSA was designed. The model consists of:The Four Layered Architecture; The Three Phase Data Flow Process; and Definition and descriptions of IoT-based elements and functions. The model was then used to drive the design, development, and evaluation of “proof of concept” prototype, the KapCha prototype. KapCha enables the optimisation of FSA using IoT techniques and features. The implementation of a sub-component of the KapCha system, in fulfilment of the research. The implementation of KapCha was applied to the context of a smart lighting environment in the case study. A two-phase evaluation was conducted to review both the theoretical model and the KapCha prototype. The model and KapCha prototype were evaluated using the Technical and Risk efficacy evaluation strategy from the Framework for Evaluation of Design Science (FEDS). The Technical Risk and Efficacy strategy made use of formative, artificial-summative and summative-naturalistic methods of evaluation. An artificial-summative evaluation was used to evaluate the design of the model. Iterative formative evaluations were conducted during the development of the KapCha. KapCha was then placed in a real-environment conditions and a summative-naturalistic evaluation was conducted. The summative-naturalistic evaluation was used to determine the performance of KapCha under real-world conditions to evaluate the extent it addresses FSA problems identified such as real-time communication and automated fault detection.
- Full Text:
- Date Issued: 2017
The relationship between intrinsic rewards, organisational commitment and organisational citizenship behaviours within an automotive manufacturer
- Authors: Weyers, Leandra
- Date: 2016
- Subjects: Organizational behavior -- South Africa Automobile industry and trade -- South Africa Incentives in industry
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/13235 , vital:27167
- Description: Intrinsic rewards, organisational commitment (OC) and organisational citizenship behaviours (OCBs) are all considered to be positive constructs in today's world of work, which could have a practically beneficial impact on the employee's career, development and success as well as the organisation's bottom line and overall effectiveness. The meaning and purpose provided by one's job combined with commitment to one's organisation as well as the display of positive, helping behaviours have all become constructs of considerable importance whilst at work. The primary objective of this research study was to investigate the relationship between the three constructs of intrinsic rewards, OC and OCBs amongst permanent employees of an automotive manufacturer in South Africa. An additional aim was to establish whether significant differences existed between the three constructs under study across various demographic variables. The researcher made use of a quantitative research method in order to conduct this study using a cross-sectional design. A composite questionnaire was used to gather the necessary data for the study, inclusive of the Intrinsic Work Rewards Scale (IWRS) which is a 25 item scale measuring the dimensions of meaningful work, varied work, flexible work, challenging work and enjoyable work; the Organisational Commitment Scale (OCS) which is an 18 item scale measuring the desire, need and obligation to remain employed by an organisation; the Organisational Citizenship Behaviour Scale (OCBS) which is consistent of 20 items measuring the behaviours of altruism, courtesy, conscientiousness, civic virtue and sportsmanship; as well as a short demographic section. The questionnaire was electronically administered to 700 employees; however, it was only completed by a sample of 250 employees with a response rate of 35.7 percent. The data was analysed by means of both descriptive and inferential statistics consistent of frequency tables, central tendency and dispersion, Cronbach's alpha testing, Pearson's Product Moment Correlations and analysis of variance. The quantitative findings indicated that all three of the measurement scales were reliably used, due to Cronbach's alpha coefficients exceeding the acceptable 0.60. Significant differences existed in terms of the demographic variables included in the study for OC and to a lesser degree for OCBs and intrinsic rewards. The most significant differences were related to job level. The results identified that strong statistically and practically significant and positive correlations are existent between the constructs of intrinsic rewards, OC and OCBs. The strongest correlations were existent between the dimensions of intrinsic rewards and OC in terms of the desire (affective commitment) and obligation (normative commitment) to remain employed by the organisation as well as the organisational citizenship behaviour (OCB) dimensions of civic virtue and conscientiousness. The strongest correlations in terms of OCBs and OC were between the OCB dimensions of civic virtue and altruism with affective commitment. The findings of this research study contribute to the literature available in terms of the constructs of intrinsic rewards, OC and OCBs and also provide statistical and practical evidence of the positive correlations between the three constructs. Consequently, the results from this study provided the management of this automotive manufacturer with important information into the intrinsic nature of their employees' jobs, the levels of OC as well as the propensity of their employees to display OCBs at work.
- Full Text:
- Date Issued: 2016
- Authors: Weyers, Leandra
- Date: 2016
- Subjects: Organizational behavior -- South Africa Automobile industry and trade -- South Africa Incentives in industry
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/13235 , vital:27167
- Description: Intrinsic rewards, organisational commitment (OC) and organisational citizenship behaviours (OCBs) are all considered to be positive constructs in today's world of work, which could have a practically beneficial impact on the employee's career, development and success as well as the organisation's bottom line and overall effectiveness. The meaning and purpose provided by one's job combined with commitment to one's organisation as well as the display of positive, helping behaviours have all become constructs of considerable importance whilst at work. The primary objective of this research study was to investigate the relationship between the three constructs of intrinsic rewards, OC and OCBs amongst permanent employees of an automotive manufacturer in South Africa. An additional aim was to establish whether significant differences existed between the three constructs under study across various demographic variables. The researcher made use of a quantitative research method in order to conduct this study using a cross-sectional design. A composite questionnaire was used to gather the necessary data for the study, inclusive of the Intrinsic Work Rewards Scale (IWRS) which is a 25 item scale measuring the dimensions of meaningful work, varied work, flexible work, challenging work and enjoyable work; the Organisational Commitment Scale (OCS) which is an 18 item scale measuring the desire, need and obligation to remain employed by an organisation; the Organisational Citizenship Behaviour Scale (OCBS) which is consistent of 20 items measuring the behaviours of altruism, courtesy, conscientiousness, civic virtue and sportsmanship; as well as a short demographic section. The questionnaire was electronically administered to 700 employees; however, it was only completed by a sample of 250 employees with a response rate of 35.7 percent. The data was analysed by means of both descriptive and inferential statistics consistent of frequency tables, central tendency and dispersion, Cronbach's alpha testing, Pearson's Product Moment Correlations and analysis of variance. The quantitative findings indicated that all three of the measurement scales were reliably used, due to Cronbach's alpha coefficients exceeding the acceptable 0.60. Significant differences existed in terms of the demographic variables included in the study for OC and to a lesser degree for OCBs and intrinsic rewards. The most significant differences were related to job level. The results identified that strong statistically and practically significant and positive correlations are existent between the constructs of intrinsic rewards, OC and OCBs. The strongest correlations were existent between the dimensions of intrinsic rewards and OC in terms of the desire (affective commitment) and obligation (normative commitment) to remain employed by the organisation as well as the organisational citizenship behaviour (OCB) dimensions of civic virtue and conscientiousness. The strongest correlations in terms of OCBs and OC were between the OCB dimensions of civic virtue and altruism with affective commitment. The findings of this research study contribute to the literature available in terms of the constructs of intrinsic rewards, OC and OCBs and also provide statistical and practical evidence of the positive correlations between the three constructs. Consequently, the results from this study provided the management of this automotive manufacturer with important information into the intrinsic nature of their employees' jobs, the levels of OC as well as the propensity of their employees to display OCBs at work.
- Full Text:
- Date Issued: 2016
A qualitative bias review of the adaptation of the WAIS-III for English-speaking South Africans
- Authors: Aston, Susan
- Date: 2006
- Subjects: Wechsler Adult Intelligence Test -- South Africa , Intelligence tests -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9939 , http://hdl.handle.net/10948/453 , http://hdl.handle.net/10948/d1011931 , Wechsler Adult Intelligence Test -- South Africa , Intelligence tests -- South Africa
- Description: In response to the growing demand for a test of cognitive ability for South African adults, the Human Sciences Research Council (HSRC) adapted the Wechsler Adult Intelligence Scales, third edition (WAIS-III) for English-speaking South Africans. However, since the publication of the South African adaptation in 2001, there has been some concern whether some bias may not still be present in the measure. Consequently, this study aimed to qualitatively explore the item content of the South African adaptation of the WAIS-III in order to identify items that might still be potentially biased with specific reference to cultural and linguistic issues. The researcher employed purposive sampling, a non-probability technique, to select psychology professionals to act as expert reviewers. The sample consisted of 20 registered psychologists, psychology lecturers and psychology interns from the predominant culture and language groups of the Eastern and Western Cape. Qualitative and quantitative data were collected by means of a Bias Review Questionnaire which consisted of fixed-choice questions, as well as sections in which specific comments could be indicated. The questionnaire was distributed to 20 selected participants who were qualified to administer psychometric measures and were registered with the Health Professionals Council of South Africa (HPCSA). Qualitative data was analysed using Tesch’s model of thematic content analysis, and five main themes relating to potential bias were identified, namely: Culture, Language, Education, Socio-economic status, and Format. The qualitative data was re-submitted to the expert review group for approval and further comment. Quantitative data obtained from the Bias Review Questionnaire was analysed by obtaining frequency counts, which were converted to percentages, per subtest and aspect reviewed. The major findings of the study were as follows: 1. Cultural bias is evident in the South African adaptation of the WAIS-III. The differential meanings ascribed to concepts, terms, phrases and words by diverse cultures impact on test performance, as does familiarity with stimulus materials used in the measure. 2. Language bias was detected against groups with English as their second or third language owing to the unfamiliar, and sometimes archaic, terms and vocabulary used in the measure. The intended meanings of the translated items are unclear and confusing for test-takers. 3. South African test-takers have experienced vastly divergent educational opportunities which impact on intelligence test performance. The measure contains potential bias against individuals from disadvantaged educational backgrounds. 4. The content of the items is not relevant to test-takers from deprived socioeconomic backgrounds that have been unable to access good-quality education. 5. Format bias was found to exist with respect to the timed tests. Cultural groups who do not value speededness are disadvantaged by the structure and format of the measure. Based on the findings of this study, certain recommendations were made. These include: 1. Additional qualitative investigation of the WAIS-III , with a view to further adaptation in an effort to eradicate bias on cultural or linguistic grounds, and 2. Conducting further Differential Item Functioning (DIF) analyses and establishing construct equivalence across cultural and linguistic groups to promote this objective. Among the contributions believed to have been made by this study are the identification of potentially biased subtests and items on the grounds of culture and language, which will facilitate possible further revision and adaptation of the measure. Additionally, the variables that were considered important influencing factors of cognitive test performance have been documented and are accessible for future research that will supplement the present study.
- Full Text:
- Date Issued: 2006
- Authors: Aston, Susan
- Date: 2006
- Subjects: Wechsler Adult Intelligence Test -- South Africa , Intelligence tests -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9939 , http://hdl.handle.net/10948/453 , http://hdl.handle.net/10948/d1011931 , Wechsler Adult Intelligence Test -- South Africa , Intelligence tests -- South Africa
- Description: In response to the growing demand for a test of cognitive ability for South African adults, the Human Sciences Research Council (HSRC) adapted the Wechsler Adult Intelligence Scales, third edition (WAIS-III) for English-speaking South Africans. However, since the publication of the South African adaptation in 2001, there has been some concern whether some bias may not still be present in the measure. Consequently, this study aimed to qualitatively explore the item content of the South African adaptation of the WAIS-III in order to identify items that might still be potentially biased with specific reference to cultural and linguistic issues. The researcher employed purposive sampling, a non-probability technique, to select psychology professionals to act as expert reviewers. The sample consisted of 20 registered psychologists, psychology lecturers and psychology interns from the predominant culture and language groups of the Eastern and Western Cape. Qualitative and quantitative data were collected by means of a Bias Review Questionnaire which consisted of fixed-choice questions, as well as sections in which specific comments could be indicated. The questionnaire was distributed to 20 selected participants who were qualified to administer psychometric measures and were registered with the Health Professionals Council of South Africa (HPCSA). Qualitative data was analysed using Tesch’s model of thematic content analysis, and five main themes relating to potential bias were identified, namely: Culture, Language, Education, Socio-economic status, and Format. The qualitative data was re-submitted to the expert review group for approval and further comment. Quantitative data obtained from the Bias Review Questionnaire was analysed by obtaining frequency counts, which were converted to percentages, per subtest and aspect reviewed. The major findings of the study were as follows: 1. Cultural bias is evident in the South African adaptation of the WAIS-III. The differential meanings ascribed to concepts, terms, phrases and words by diverse cultures impact on test performance, as does familiarity with stimulus materials used in the measure. 2. Language bias was detected against groups with English as their second or third language owing to the unfamiliar, and sometimes archaic, terms and vocabulary used in the measure. The intended meanings of the translated items are unclear and confusing for test-takers. 3. South African test-takers have experienced vastly divergent educational opportunities which impact on intelligence test performance. The measure contains potential bias against individuals from disadvantaged educational backgrounds. 4. The content of the items is not relevant to test-takers from deprived socioeconomic backgrounds that have been unable to access good-quality education. 5. Format bias was found to exist with respect to the timed tests. Cultural groups who do not value speededness are disadvantaged by the structure and format of the measure. Based on the findings of this study, certain recommendations were made. These include: 1. Additional qualitative investigation of the WAIS-III , with a view to further adaptation in an effort to eradicate bias on cultural or linguistic grounds, and 2. Conducting further Differential Item Functioning (DIF) analyses and establishing construct equivalence across cultural and linguistic groups to promote this objective. Among the contributions believed to have been made by this study are the identification of potentially biased subtests and items on the grounds of culture and language, which will facilitate possible further revision and adaptation of the measure. Additionally, the variables that were considered important influencing factors of cognitive test performance have been documented and are accessible for future research that will supplement the present study.
- Full Text:
- Date Issued: 2006
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