Thesis (MPH)--University of Limpopo, 2010. / Physical Ability Analysis (PAA) is a physical work capacity indicator for the health and wellbeing of the organisational workforce. Employees doing powerline work and similarly physically demanding positions are assessed using a battery of tests called the physical ability analysis (PAA), inclusive of a cardiovascular test component, a strength component for upper body and lower body, the endurance component, and a record of health problems. The results are classified into five categories that are indicative of their physical work ability. It is therefore crucial that a high level of physical capacity is maintained to ensure a sustainable workforce. Objective: The aim of the study was to determine the physical ability and common health problems among powerline electricians in Eskom Distribution over time, and determine the extent to which variations, if any exist, could be explained by the socio-demographic characteristics, health problems or lifestyle habits. Methods: A cross-sectional analysis of Eskom Distribution’s powerline electricians was done using occupational medical records found in the institutional database for the period of 2003, 2005 and 2008. Results: A total of 50 records meeting the selection criteria were analyzed. At the time of the study, the power line electricians were old as 94% of them were over 50 years old, overweight (46%), and suffering from chronic conditions such as hypertension (22%), diabetes (8%). In addition, 19% suffered from back injuries, 2% from knee injuries, while 32% smoked cigarettes. Given their health profile, they became sicker for longer periods as reflected by the increasing number of sick leave days (95% of the cases that took leave had hypertension). The physical ability levels improved from baseline (46%) to 62% in 2008. A shift of PAA2 participants in the 47 – 51year age group was the reason for the increase and the youngest group of electricians remained in PAA category 1 throughout the study period. Muscle function was a strong predictor for meeting the required physical ability level, most measurements that were significantly associated with physical ability score, leg strength, noted as the strongest predictor among them (OR 123.00; p = 0.00, 95% CI, 9.22-1573.00), followed by abdominal endurance (OR 43.49; p = 0.01, 95% CI, 2.49-786.13) and grip strength of the right hands, with similar odds to the abdominal strength (OR 41.00; p = 0.00, 95% CI, 3.65-461.04) with back strength at (OR 28.50; p = 0.01, 95% CI, 2.37-342.61). Conclusion: With regard to physical ability, the study concludes that age is a strong predictor for physical ability as the youngest group ( 49years old) of electricians remained in PAA1 throughout the study period, and were approximately four times likely to meet the required 12 physical ability standard than their older counterparts and that regular physical assessment and rehabilitation have been effective in maintaining the physical ability of electricians.

<P> The limited strength model of self-regulation describes self-regulation as a limited, consumable, and renewable internal resource that is depleted when people attempt to control their emotions, thoughts or behaviours (Baumeister & colleagues 1994; 1996). Evidence indicates a consistent relationship across emotional, mental, and physical domains that task performance in all of these areas draws on the same limited resource and is governed by processes occurring within the central nervous system (Galliot, et al., 2007). The main purpose of this study was to examine the effects of self-regulation depletion on muscle activity (EMG) and physical stamina via an isometric task (ankle dorsiflexion). A secondary objective was to investigate trait self-control as an effect modifier of cognitive self-regulation depletion effects on physical stamina. It was hypothesized that individuals would show a greater decline in isometric endurance performance after undergoing a self-regulatory depletion manipulation compared to when they were exposed to· a non-depletion task of similar duration. It was also expected that participants would exhibit greater increases in EMG amplitude after being depleted compared to when not depleted. Additionally, it was hypothesized that people who scored lower on a measure of trait self-control would demonstrate greater depletion effects (i.e., greater pre-to-post performance differences) than those who scored higher on trait self-control. The study was a within-subjects cross-over design involving 31 informed and consenting sedentary university students (M^age= 21.72 ± 2.57 years). Participants were stratified by gender and randomized to experience either cognitive depletion (modified Stroop task) or non-depletion (colour word reading task) for their first trial. In each trial, they completed two isometric ankle dorsiflexion endurance trials at 50% of their MVC (predetermined by initial MVC) separated by the cognitive task. Due to an unexpected differential carryover effect of exposure order, analysis of the data was carried out for each testing session, with primary analysis focused on Time 1 as suggested by Grizzle (1965). Time 1 data indicated a trend towards significance (p = .13) for performance declines being greater in the depletion group compared to the non-depletion group, and a small effect size of .27 was detected, which is comparable to findings in other related studies (Bray et al., 2008; Muraven & Shmueli, 2006). No statistically significant differences emerged for muscle activity in the tibialis anterior for the depletion group compared to the non-depletion group. Those individuals who scored lower on trait self-regulation showed a non-significant trend towards greater depletion effects on muscular endurance performance than those who scored higher on trait self-regulation (p = .13; Cohen's d = .32). Results support the limited strength model of self-regulation and the trait self-control as an·individual difference factor affecting self-regulation, but raise questions regarding the role of central fatigue effects on muscular activation following self-regulatory depletion. </p> / Thesis / Master of Science (MSc)

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2009. / Härtill 5 uppsatser.

In order to examine the effects of prelatent/latent iron deficiency on physical work capacity and selected muscle enzyme activities, forty female subjects were studied before and after eight weeks of supplementation with either oral iron or a matching placebo. Initially, female volunteers engaged in regular endurance running were screened for iron deficiency by blood analysis (serum ferritin and hemoglobin). Forty non-anemic subjects with deficient iron stores underwent physiological and anthropometric tests to obtain a comprehensive profile. The specific physical work capacity tests were alactic and lactacid power on the Wingate cycle ergometer test, lactacid capacity on the anaerobic speed test, anaerobic (ventilatory) threshold using gas exchange variables, V0₂ max. and the max. treadmill velocity during the V0₂ max. test. Muscle biopsy samples pre-, and post- treatment were assayed for citrate synthase and alpha-glycerophosphate dehydrogenase activity. Treatment was oral iron supplementation (320 mg ferrous sulfate = 100 mg elemental iron taken as SLOW-Fe® twice a day) or a matching placebo. The subjects were randomly assigned to one of the treatment groups and a double-blind method of administration of the supplements was used. It was hypothesized that work capacity would be enhanced following oral iron supplementation, possibly due to the repletion of iron containing oxidative enzymes important in energy production. Results could not strongly support this hypothesis with the difference between the two groups on the work capacity and enzyme activity variables being statistically nonsignificant. Serum ferritin values rose from a mean of 12.4+4.5 to 37.7+19.7 ngml⁻¹ for the experimental group and 12.2±4.3 to 17.2±8.9 for the controls; (p=0.0025). Hemoglobin levels remained fairly constant for both treatment groups; 13.4±0.6 to 13.5±0.5 gdl⁻¹ (experimental), and 13.0±0.6 to 13.1+0.5 (control); (p=0.6). Pre to post values on the work capacity variables, experimental vs control respectively were: Alactic power, 8.8 to 8.4 watts-kg⁻¹ body wt. vs 8.4 to 8.2; lactacid capacity, 6.9 to 6.9 watts-kg⁻¹ body wt. vs 7.0 to 6.0; anaerobic speed test, 41.3 to 45.1 seconds vs 43.7 to 44.8; anaerobic threshold, 7.4 to 7.5 mileshour⁻¹ vs 7.2 to 7.2; V0₂ max, 51.3 to 52.7 ml-kg⁻¹ min⁻¹ vs 50.6 to 50.6; max velocity during V0₂ max, 9.8 to 9.8 mileshour⁻¹ vs 9.6 to 9.5. Except for alactic power, the change in work capacity favored the iron treated group. Noting this trend, further study may be warranted. Prelatent/latent iron deficiency appeared not to depress the activities of the two enzymes measured. Cytoplasmic alpha-glycerophosphate dehydrogenase activity rose from 0.066 to 0.085 units for the experimental group (p=.58) vs .058 to .066 for the control group and citrate synthase activity changed from 0.047 to 0.048 (experimental) vs 0.039 to 0.042 (control). It can be concluded that eight weeks of iron supplementation to prelatent/latent iron deficient, physically active females does not significantly enhance work capacity nor the activity of 2 oxidative muscle enzymes (citrate synthase and cytoplasmic alpha-glycerophosphate dehydrogenase). Within the limitations of this study the presence of a serum ferritin below 20 ng-ml⁻¹ does not pose a significant handicap to anaerobic or aerobic capacity. / Graduate and Postdoctoral Studies / Graduate

Fung Man-yi, Wendy. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 84-106). / Text in English; abstracts and appendices in English and Chinese. / Fung Man-yi, Wendy. / Acknowledgments --- p.i / Presentation --- p.iii / Abstract --- p.iv / Table of Contents --- p.viii / List of Tables --- p.x / List of Figures --- p.xi / Chapter CHAPTER ONE --- Introduction --- p.1 / Research Background --- p.1 / Purpose of the Study --- p.5 / Justification of the Study --- p.6 / Hypotheses --- p.6 / Definition of Terms --- p.7 / Assumptions --- p.8 / Delimitations --- p.8 / Limitations --- p.9 / Significance of the Study --- p.9 / Chapter CHAPTER TWO --- Review of Literature --- p.10 / "Engergy Metabolism During Prolonged, Submaximal Exercise" --- p.10 / "Causes of Fatigue During Prolonged, Submaximal Exercise" --- p.16 / Factors Influencing Muscle Glycogen Resynthesis During Recovery --- p.21 / Factors Influencing Rehydration During Recovery --- p.27 / Effect of Muscle Glycogen Replenishment During Recovery on Subsequent Endurance Capacity --- p.30 / Effect of Rehydration During Recovery on Subsequent Endurance Capacity --- p.32 / Effect of Glycemic Index Meals Before Exercise on Exercise Performance --- p.33 / Chapter CHAPTER THREE --- Methodology --- p.37 / Participants --- p.37 / Equipment and Instrumentation --- p.37 / Standardized Experimental Procedures --- p.38 / Collection and Analysis of Blood Samples --- p.42 / Preliminary Measurements --- p.45 / Dietary Analyses and Training Control --- p.50 / Preliminary Testing --- p.51 / Statistical Analysis --- p.54 / Chapter CHAPTER FOUR --- Results --- p.56 / Run Time to Exhaustion --- p.56 / Dietary Analysis --- p.57 / Postprandial Responses of the Test Meals During Screening Session --- p.58 / Postprandial Responses During Recovery --- p.60 / Responses During Exercise and Recovery --- p.62 / Body Mass Changes and Fluid Balance --- p.74 / Changes in Plasma Volume and Urine Volume --- p.75 / Summary of the Results --- p.76 / Chapter CHAPTER FIVE --- Discussion --- p.77 / Recommendations and Applications --- p.83 / References --- p.84 / Appendixes --- p.107

Siu Ming Fai Parco. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 101-117). / Text in English; abstracts in English and Chinese. / Siu Ming Fai Parco. / Acknowledgments --- p.i / Abstract --- p.iii / Table of Contents --- p.vii / List of Tables --- p.ix / List of Figures --- p.x / Chapter CHAPTER ONE --- Introduction --- p.1 / Research Background --- p.1 / Purpose of the Study --- p.6 / Hypotheses --- p.6 / Definition of Terms --- p.7 / Assumptions --- p.8 / Delimitations --- p.9 / Limitations --- p.9 / Chapter CHAPTER TWO --- Review of Literature --- p.10 / Importance of Muscle Glycogen Resynthesis During Recovery from Exercise --- p.10 / Factors Affecting Muscle Glycogen Resynthesis --- p.10 / Muscle Glycogen Resynthesis and Subsequent Endurance Capacity --- p.17 / Importance of Rehydration on Recovery from exercise --- p.22 / Factors Affecting Rehydration --- p.22 / Rehydration and Subsequent Endurance Capacity --- p.25 / Glycemic Index Foods and Exercise --- p.26 / Definition of Glycemic Index (GI) --- p.26 / Ingestion of GI Foods Before Exercise --- p.28 / Ingestion of GI Foods During Recovery --- p.33 / Frequency of CHO Ingestion and Exercise --- p.36 / Chapter CHAPTER THREE --- Methodology --- p.39 / Participants --- p.39 / Equipment and Instrumentation --- p.39 / Preliminary Measurements --- p.40 / Dietary Analysis and Training Control --- p.45 / Preliminary Testing --- p.46 / Standardized Experimental Procedure --- p.51 / Collection and Analysis of Blood Sample --- p.57 / Statistical Analysis --- p.61 / Chapter CHAPTER FOUR --- Results --- p.62 / Run Time to Exhaustion --- p.63 / Dietary Analysis --- p.63 / Postprandial Responses of the Prescribed Foods During Screening Test --- p.64 / Postprandial Responses During Recovery of Main Trial --- p.67 / Metabolic and Physiological Responses During Exercise and Recovery --- p.70 / "Body Mass Change, Fluid Balance and Urine Volume" --- p.89 / Changes in Plasma Volume --- p.90 / Summary of the Results --- p.91 / Chapter CHAPTER FIVE --- Discussion --- p.92 / Recommendations and Applications --- p.99 / References --- p.101 / Appendices --- p.118

Introdução: Força, resistência e atividade muscular são uma área importante de pesquisa e avaliação contribuindo para um melhor entendimento de aspectos musculoesqueléticos de mecanismos de dor e lesão. No entanto, a utilização de testes que avaliem a região lombopélvica ainda é controversa, pois apesar de muitos testes clínicos estarem disponíveis na literatura, ainda não estão estabelecidos quais os mais confiáveis na prática clínica. Objetivos: Estabelecer valores de referência, determinar confiabilidade intra e interexaminador e as medidas de erro de um conjunto de testes clínicos que avaliam a região lombopélvica em indivíduos assintomáticos de diferentes gêneros, faixas etárias e níveis de atividade física. Materiais e Métodos: Para os valores de referência, 152 indivíduos (79 homens, 73 mulheres) estratificados por gênero, faixa etária e nível de atividade física realizaram um conjunto de nove testes clínicos: força isométrica máxima de abdutores, extensores, flexores e rotadores laterais de quadril, resistência nas posições de ponte lateral, ponte frontal, flexores e extensores lombares e atividade muscular da região lombopélvica. Para a confiabilidade, 33 indivíduos foram avaliados por dois examinadores em um intervalo de 3 a 7 dias, onde realizaram aleatoriamente o mesmo conjunto de testes. As medidas de confiabilidade foram avaliadas pelo Coeficiente de Correlação Interclasse (CCI2,1) e as medidas de erro definidas pelo Erro Padrão da Medida (EPM) e pela Mínima Mudança Detectável (MMD). Resultados: Foram observadas diferenças significativas (p<0.05) nos testes clínicos para as variáveis: gênero, faixa etária e nível de atividade física e estabelecidos valores de referência para cada grupo. Todos os testes apresentaram valores de confiabilidade excelente com CCI (IC 95%) maior que 0.8 para as confiabilidades intra e interexaminador; os valores da MMD foram superiores à média do EPM em todos os testes. Conclusão: Os resultados do presente estudo apontam valores de referência que contribuem com o estabelecimento de referências para auxiliar na tomada de decisões clínicas. Além disso, este conjunto de 10 testes apresentou confiabilidade intra e interexaminador bem como valores de EPM e MMD, confirmando a possibilidade de seu uso na prática clínica. / Background: The assessment of the lumbopelvic region is useful for many musculoskeletal dysfunctions. Several clinical tests are commonly used to assess this region, however, reference values for clinical assessments and results concerning method, reliability and error measurements of these tests have not been reported. Objectives: To establish reference values and to determine intra and interrater reliability, standard error of measurement (SEM) and minimum detectable change (MDC) of a set of clinical tests used for assessing the lumbopelvic region in asymptomatic volunteers of different gender, age groups and physical activity levels. Methods: For reference values, 152 subjects (79 men, 73 women) divided by gender, age group and physical activity levels, performed nine clinical tests: Maximum voluntary isometric strength of hip abductors, extensors, flexors and lateral rotators, transversus abdominis(TrA) muscle activity (using a Pressure Biofeedback Unit), prone and side bridges, trunk flexor and extensor endurance tests. To measure reliability, 33 individuals performed the same set of tests, in random order within a week period. Intrarater and interrater analysis were assessed using the Intraclass Correlation Coefficient (ICC) and the error measurements were defined by using the SEM and the MDC. Results: Reference values were established for each group and our results showed significant (p<0.05) differences concerning gender, age group and physical activity levels in clinical tests. In general, strength differences were related to gender and physical activity levels and endurance results could be related to interactions between gender, age group and physical activity levels. All tests presented good reliability indices with an ICC (95%CI) higher than 0.8 for the intrarater and interrater reliability; MDC values were greater than mean of SEM in all tests, confirming its usage for clinical practice assessments. Conclusion: Reference values are necessary to help clinicians in the evaluation of subjects and these results can contribute for clinical practice in providing clinical training targets. Also, this set of tests presented good intra and interrater reliability measures of strength, endurance and TrA muscle activity test as well as SEM and MDC values, confirming its use for assessing the lumbopelvic region.

Introdução: Força, resistência e atividade muscular são uma área importante de pesquisa e avaliação contribuindo para um melhor entendimento de aspectos musculoesqueléticos de mecanismos de dor e lesão. No entanto, a utilização de testes que avaliem a região lombopélvica ainda é controversa, pois apesar de muitos testes clínicos estarem disponíveis na literatura, ainda não estão estabelecidos quais os mais confiáveis na prática clínica. Objetivos: Estabelecer valores de referência, determinar confiabilidade intra e interexaminador e as medidas de erro de um conjunto de testes clínicos que avaliam a região lombopélvica em indivíduos assintomáticos de diferentes gêneros, faixas etárias e níveis de atividade física. Materiais e Métodos: Para os valores de referência, 152 indivíduos (79 homens, 73 mulheres) estratificados por gênero, faixa etária e nível de atividade física realizaram um conjunto de nove testes clínicos: força isométrica máxima de abdutores, extensores, flexores e rotadores laterais de quadril, resistência nas posições de ponte lateral, ponte frontal, flexores e extensores lombares e atividade muscular da região lombopélvica. Para a confiabilidade, 33 indivíduos foram avaliados por dois examinadores em um intervalo de 3 a 7 dias, onde realizaram aleatoriamente o mesmo conjunto de testes. As medidas de confiabilidade foram avaliadas pelo Coeficiente de Correlação Interclasse (CCI2,1) e as medidas de erro definidas pelo Erro Padrão da Medida (EPM) e pela Mínima Mudança Detectável (MMD). Resultados: Foram observadas diferenças significativas (p<0.05) nos testes clínicos para as variáveis: gênero, faixa etária e nível de atividade física e estabelecidos valores de referência para cada grupo. Todos os testes apresentaram valores de confiabilidade excelente com CCI (IC 95%) maior que 0.8 para as confiabilidades intra e interexaminador; os valores da MMD foram superiores à média do EPM em todos os testes. Conclusão: Os resultados do presente estudo apontam valores de referência que contribuem com o estabelecimento de referências para auxiliar na tomada de decisões clínicas. Além disso, este conjunto de 10 testes apresentou confiabilidade intra e interexaminador bem como valores de EPM e MMD, confirmando a possibilidade de seu uso na prática clínica. / Background: The assessment of the lumbopelvic region is useful for many musculoskeletal dysfunctions. Several clinical tests are commonly used to assess this region, however, reference values for clinical assessments and results concerning method, reliability and error measurements of these tests have not been reported. Objectives: To establish reference values and to determine intra and interrater reliability, standard error of measurement (SEM) and minimum detectable change (MDC) of a set of clinical tests used for assessing the lumbopelvic region in asymptomatic volunteers of different gender, age groups and physical activity levels. Methods: For reference values, 152 subjects (79 men, 73 women) divided by gender, age group and physical activity levels, performed nine clinical tests: Maximum voluntary isometric strength of hip abductors, extensors, flexors and lateral rotators, transversus abdominis(TrA) muscle activity (using a Pressure Biofeedback Unit), prone and side bridges, trunk flexor and extensor endurance tests. To measure reliability, 33 individuals performed the same set of tests, in random order within a week period. Intrarater and interrater analysis were assessed using the Intraclass Correlation Coefficient (ICC) and the error measurements were defined by using the SEM and the MDC. Results: Reference values were established for each group and our results showed significant (p<0.05) differences concerning gender, age group and physical activity levels in clinical tests. In general, strength differences were related to gender and physical activity levels and endurance results could be related to interactions between gender, age group and physical activity levels. All tests presented good reliability indices with an ICC (95%CI) higher than 0.8 for the intrarater and interrater reliability; MDC values were greater than mean of SEM in all tests, confirming its usage for clinical practice assessments. Conclusion: Reference values are necessary to help clinicians in the evaluation of subjects and these results can contribute for clinical practice in providing clinical training targets. Also, this set of tests presented good intra and interrater reliability measures of strength, endurance and TrA muscle activity test as well as SEM and MDC values, confirming its use for assessing the lumbopelvic region.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Thesis--University of Jyväskylä. / Text in English; abstract and summary also in Finnish. Thesis t.p. inserted. Includes bibliographical references (p. 69-84).