A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science in Physiotherapy. Johannesburg, 2014 / Cycling has grown in popularity as a sport and is rated as one of the top 15 most popular sports in South Africa with more than 420 000 participants. Cyclists spend long continuous hours on the bicycle in an awkward position, which leads to unique overuse injuries. Overuse injuries in cyclists have been estimated to be as high as 85% with lower back and pelvis pain (LBPP) among the most common. The lower back and pelvis is the foundation the cyclist use for powering and controlling the bicycle and optimal functioning thereof is essential for optimal comfort and performance in cycling. The prolonged forward flexed position of the cyclist on the bicycle is regarded as one of the main contributors to LBPP in cyclists. Cyclists with LBPP are known to assume a position of greater lumbar flexion compared to those without but the reason for this has not been extensively explored. The purpose of this study was therefore to not only establish the prevalence of LBPP in cyclists in South Africa, but also identify factors associated with it in cyclists. The factors were considered in three broad categories: (1) training methods used, (2) intrinsic functioning of the cyclist and (3) bicycle set-up. Intrinsic and bicycle set-up factors included were those proposed to influence the forward-backward and side-to-side position of the cyclist on the bicycle and thereby lead to the development of LBPP in cyclists. The study had a cross-sectional descriptive design and comprised of two parts: a questionnaire (survey) investigating the prevalence of LBPP in cyclists together with the training methods used, and a physical assessment of the factors proposed to be associated with LBPP in cyclists. All cyclists belonging to cycling clubs registered with Cycling South Africa were invited to complete the online survey. From there, cyclists could indicate willingness to undergo a physical assessment which was done in the greater Gauteng area. The physical assessment included the following measurements: the lumbar curvature on the bicycle in all three handlebar positions, strength of gluteus maximus and gluteus medius, extensibility of the hamstring muscle group, control of lumbar movement in the direction of flexion, neurodynamics, active straight leg raise for load transfer, one leg stance test for lateral shift of the pelvis, leg-length discrepancy and bicycle set-up (saddle height, set-back and angle, handlebar height, forward reach, cleat position). The study revealed a lifetime prevalence of 65% for LBPP among cyclists in South Africa. Of the factors assessed, only the lumbar curvature in the brake lever position i.e. flexion of the lumbar spine (p=0.03) and the weakness of gluteus medius (Gmed) (p=0.05) were significantly related to LBPP in cyclists. This study was the first to assess the relationship between so many different factors and LBPP in cyclists, and the largest of its kind in cycling. Understanding the relationship between these factors and LBPP in cyclists can guide the development of preventative strategies and interventions with the aim of reducing the occurrence and recurrence of LBPP in cyclists and limiting the impact thereof.

Introduction Low back pain can be influenced by demographic, lifestyle and co-morbid factors. No studies have been done on the relationship between these factors and low back pain in hospital employees in South Africa. The aim of this study was to determine which of these factors was present and how they influenced low back pain in staff employed at a district hospital in South Africa. Methods The study used a self-administered questionnaire on staff employed at the hospital. Results Results indicated that the point prevalence for low back pain was 47%. Most of the employees were female nurses aged between 26 and 40 years with BMI values higher than normal. The majority of the employees participated in exercises although this was mainly for 1 to 2 times a week. Among the demographic factors, only female gender was associated with increased risk of low back pain (OR 1,67 CI 1,04 ; 2,69) while for the lifestyle factors, participation in group exercises was a protective factor against low back pain (OR 1,66 CI 1,02 ; 2,70). Perceived stress all the time increased the risk of low back pain (OR 3,47 CI 1,46 ; 8,23). None of the isolated co-morbid diseases were associated with the presence of low back pain. Conclusion The prevalence of low back pain among Tshwane district hospital employees is high. Female gender and a high level of perceived stress increase the risk of low back pain while participation in group exercise reduces the risk of low back pain.

MSc, Physiotherapy, Faculty of Health Sciences, University of the Witwatersrand / The Association between Trunk Muscle Endurance and Lumbar-Pelvic Instability in Adolescent Low Back Pain Françoise Lewis Supervisors: Wendy-Anne Wood, Benita Naude. Low back pain (LBP) is a common cause of discomfort in modern society, and the prevalence of LBP in the adolescent population is high and has a predictive value for the occurrence of LBP as an adult. The aim of the study was to investigate the association between adolescent LBP and trunk muscle endurance and lumbar-pelvic instability, as well as the association between trunk muscle endurance and lumbar-pelvic instability. Sports and physical activity participation, sedentary activity participation and a family history were also investigated as they have been identified in previous studies as potential risk factors. The study was a cross sectional study of 80 adolescents in grade 8 to grade 11, aged 12 to 17 year , at three high schools in Gauteng, who agreed to participate in the study. Data was collected by means of a validated questionnaire and a physical examination. The level of significance for as sociated factors was set at 0.05. The results revealed a lifetime prevalence of 82.50%, one year prevalence of 78.80% and point prevalence of 23.80%. Adolescents with LBP have decreased endurance of the trunk extensor muscles but increased endurance of the trunk flexor muscles, which is statistically significant (p=0.044) . Lumbar-pelvic instability is not associated with adolescent LBP. Extensor trunk muscle endurance and poor lumbar pelvic stability show an association (p=0.031), with those adolescents with decreased trunk extensor muscle endurance presenting with poor lumbar-pelvic stability. A family history of LBP is significant for point prevalence of LBP (p=0.012), and one-year prevalence of LBP is marginally significant (p=0.086). Low activity level particpation was reported by a large percentage of all subjects. Sedentary activity participation is moderate in the LBP group, but the results are not statistically significant . There is a need for preventative srategies to decrease the prevalence of adolescent LBP. Increased awareness of LBP and potential risk factors needs to be addressed.

Motivation Occupational driving has often been associated with a high prevalence of low-back pain (LBP). Truck drivers in the petrochemical industry in South Africa are vulnerable to occupational related LBP because of the very nature of their job, and this vulnerability has to date not been quantified. The individual and job factors that contribute to cause this pain are diverse and might include prolonged sitting, exposure to whole-body vibration, heavy physical work, smoking and other psychosocial factors. Studies on the prevalence and knowledge of the risk factors associated with occupational related LBP are important since they allow not only for the determination of the impact of the condition on society or on a given social stratum, but can also help to organize health services and channel investments necessary for the prevention and control of occupational related LBP. Aim The aim of this study was to determine the prevalence of occupational related LBP in a defined cohort of truck drivers and to ascertain if certain risk factors i.e. demographic factors of the truck drivers, manual material handling (heavy physical work), static work posture and perceived levels of whole-body vibration are associated with truck driving and LBP. Methods The study design chosen was descriptive, cross-sectional and quantitative in nature. For the study, the widely established “Standardized Nordic Questionnaire” (SNQ) was used to collect data. The questionnaire was divided into three sections, viz. biographical, low-back pain, and risk factors for ease of completion by the participants of this study. A total of 450 drivers participated in the study by completing the questionnaire. SPSS version 15.0 (SPSS Inc., Chicago, Illinois, USA) was used to analyze the data. Descriptive and inferential statistics was used in the analysis of the data. Results Of the 450 drivers, 385 (86%) experience LBP and 65 (14%) reported to have not experienced any form of LBP. On the scale of 0 to 10, 68 drivers (15%) indicated that they had pain as bad as it could be, whereas 32 drivers (7%) indicated that they suffered no back pain at all. When the severity of the pain was categorised, as low, medium and high, 40.5 % of the LBP respondents indicated that they had a high severity of LBP. Smoking, static work posture and total years of driving were all found to be significantly associated with LBP. Whole-body vibration, body mass index (BMI) and heavy physical work were found to have no association with LBP which was not expected. Conclusion The prevalence of occupational related low-back pain in petrochemical truck drivers was 89%. Smoking, static work posture and total years of driving were the risk factors associated with LBP amongst the truck drivers.

Thesis (Ph. D.)--Virginia Commonwealth University, 2006. / Prepared for: Dept. of Health Administration. Bibliography: leaves 176-192. Also available online.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 90-96). Also available on the World Wide Web.

Background Obesity is associated with an increased risk of back pain, attributed to elevated mechanical load. Back injury risk is also determined by movement patterns (kinematics) and physiological factors (exertion, muscle activation). Lifting, particularly repetitive, is the most frequently cited injurious activity. However, in spite of the obvious relation, a paucity of information exists quantifying the interaction of obesity and repetition during lifting. Purpose To determine the effects of obesity and repetition on mechanical, kinematic and physiological lifting outcomes. Methods: An individual-specific, biomechanical model (based upon 3D photogrammetry) was developed to estimate the effect of obesity on back load during lifting (study 1). Lifting strategy and physiological outcomes related to obesity were examined in a fixed-pace, repetitive lifting task (study 2). The effect of task constraints on lifting strategy of high and normal BMI individuals were determined (study 3), followed by an evaluation of muscle activation responses during a repetitive trunk motion similar to that encountered during lifting (study 4). Results: Obesity-specific alterations of important determinants of back load (inertia, CMloc) were revealed. Obesity was related to a substantial increase in back load (M=+197.3, SE=16.8 Nm about L5/S1), however the effect differed across lifting tasks. The lifting strategy of high-BMI individuals was characterized by an increased distance to the external mass (M=+4.7, SE=1.8 cm) and shorter lift duration (M=230, SE=130 msec), with increased cardiovascular effort (M=+7.4, SE=3.4% HRmax) but no change in perceived exertion. Lifting frequency was not a major determinant of lifting strategy, however strategy was influenced by the presence and type of external pacing. A phase-specific, rapid alteration in muscle activation response was evident in the MMG signal during the initial repetitions of a repetitive trunk motion. Conclusion: The effect of obesity during lifting is task-dependent, and cannot be attributable solely to mechanical factors. Future studies should consider tasks that are unconstrained, and examine the initial familiarization period of repetitive tasks, specifically the lowering phase of motions. These findings have relevance to back injury mechanisms related to obesity and the design of injury prevention programs for individuals with a high BMI.

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Background Obesity is associated with an increased risk of back pain, attributed to elevated mechanical load. Back injury risk is also determined by movement patterns (kinematics) and physiological factors (exertion, muscle activation). Lifting, particularly repetitive, is the most frequently cited injurious activity. However, in spite of the obvious relation, a paucity of information exists quantifying the interaction of obesity and repetition during lifting. Purpose To determine the effects of obesity and repetition on mechanical, kinematic and physiological lifting outcomes. Methods: An individual-specific, biomechanical model (based upon 3D photogrammetry) was developed to estimate the effect of obesity on back load during lifting (study 1). Lifting strategy and physiological outcomes related to obesity were examined in a fixed-pace, repetitive lifting task (study 2). The effect of task constraints on lifting strategy of high and normal BMI individuals were determined (study 3), followed by an evaluation of muscle activation responses during a repetitive trunk motion similar to that encountered during lifting (study 4). Results: Obesity-specific alterations of important determinants of back load (inertia, CMloc) were revealed. Obesity was related to a substantial increase in back load (M=+197.3, SE=16.8 Nm about L5/S1), however the effect differed across lifting tasks. The lifting strategy of high-BMI individuals was characterized by an increased distance to the external mass (M=+4.7, SE=1.8 cm) and shorter lift duration (M=230, SE=130 msec), with increased cardiovascular effort (M=+7.4, SE=3.4% HRmax) but no change in perceived exertion. Lifting frequency was not a major determinant of lifting strategy, however strategy was influenced by the presence and type of external pacing. A phase-specific, rapid alteration in muscle activation response was evident in the MMG signal during the initial repetitions of a repetitive trunk motion. Conclusion: The effect of obesity during lifting is task-dependent, and cannot be attributable solely to mechanical factors. Future studies should consider tasks that are unconstrained, and examine the initial familiarization period of repetitive tasks, specifically the lowering phase of motions. These findings have relevance to back injury mechanisms related to obesity and the design of injury prevention programs for individuals with a high BMI.

This thesis aims to apply neural networks in the classification of human patterns of movement and to compare the accuracy of this technique with existing methods (conventional statistics and clinical assessment). Three different examples of human movement and one of posture were chosen for study and a variety of biomechanical parameters used to describe them. The temporal parameters of gait patterns, related to speed of walking and walking with splinted knee or weighted leg, were recorded. The angular displacement of both hips and knees was measured during stepping up or down steps of five different heights. Different standing postures were studied by measuring the disposition of body landmarks associated with imagined moods of human subjects. Finally, changes of the sit-stand-sit manoeuvre due to chronic low back pain, expressed as joint movement and forces exerted on the ground, were recorded. Patterns were classified by neural networks, linear discriminant analysis and, in the case of sit-stand patterns, by qualified clinicians. By altering the number of variables to discriminate between patterns, benefits of the above classifiers were identified. The success in classification of the measured patterns by neural networks was found to have an accuracy at least as high as that of linear discriminant analysis. A neural network is a useful tool for the discrimination of patterns of human movements; its main advantage is the ability to deal with a large number of predictor variables. A successfully trained and tested neural networks can easily be set up in a computer and, on the evidence presented, could be used to help clinicians diagnose or assess pathological patterns of movement.