MSc (Occupational Therapy), Faculty of Health Sciences, University of the Witwatersrand / Ergonomic interventions, addressing work and lifestyle factors, seem more effective in reducing computer related upper limb repetitive strain injury (RSI).This study considered the efficacy of such a programme on the resolution of RSI symptoms. A cross sectional survey, of 325 computer workers in a medical aid company call centres, in Gauteng, South Africa was used to establish a point prevalence of 30.23% for RSI symptoms, which correlates with those found elsewhere. An occupational therapy ergonomic intervention was then designed and piloted for efficacy. A randomised control trial conducted on 37 participants with RSI used the programme and computer generated “Break Software”. The six week intervention included the assessment of: three physical outcome measures and lifestyle factors for, the experimental and control groups. Results indicated positive effects on pain, grip strength, and lifestyle factors including feelings of inefficiency, pressure at the end of the day, depression and work capacity, but little extrapolation of ergonomic knowledge to the workplace.

The general purpose of this study was to examine factors that may influence acceleration characteristics of the upper body during walking, thereby clarifying the means by which the postural system facilitates dynamic stability of the upper body during walking. Upper body accelerations were measured during a range of straight-line walking tasks. Time domain, frequency domain, signal regularity and coupling analyses were used to 1) provide new insight into gait-related upper body accelerations during walking in normal healthy adults, and 2) determine how the postural system accommodates to perturbations that challenge upper body stability during walking. The specific perturbations to the postural system that were examined in the present study were the normal ageing process, changes in walking speed, and fatigue of the cervical and lumbar erector spinae. In general, the patterns of accelerations measured at the level of the head were an attenuated version of those at the lower trunk during normal walking. Power spectral analysis revealed that both the head and lower trunk in the anterior-posterior (AP) and vertical directions (VT) directions were characterised by a single peak frequency corresponding the step frequency during normal walking. However, the most notable of all attenuation profiles was the difference between accelerations of the head and lower trunk in the mediolateral (ML) direction. ML trunk accelerations were characterised by multiple low amplitude frequency peaks, which were attenuated to a single peak at the head corresponding to stride frequency. The coupling between acceleration directions was greater for the head than the lower trunk, suggesting that the postural system promotes a coordination strategy which enhances global stability of the head. Subdividing the upper body into neck and trunk segments facilitated a more comprehensive description how the gait-related oscillations are prevented from impacting on the motion of the head. Overall, acceleration amplitude, power content, and regularity were predominantly regulated by the trunk segment, especially for the AP and ML directions. This suggests that the trunk segment plays a critical role in modulating the amplitude and structure of gait-related oscillations prior to reaching the neck segment and thus the head. It was envisaged that examining factors that may challenge the individual (the normal ageing process), and the walking task (changes in walking speed, and induced fatigue of the upper body), would provide new insight into the extent to which the postural system prioritises head stability during walking. Regardless of the challenges imposed on the postural system due to the ageing process, upper body movement was organised in a manner which assisted in maintaining a degree of head stability comparable to those observed under normal walking conditions. Similarly, the importance that the postural system places on maintaining head stability was evident in the attenuation characteristics of the trunk and neck segments when walking speed was manipulated, and neuromuscular fatigue induced. Manipulating walking speed highlighted the critical role that the trunk segment has in regulating upper body accelerations arising from gait-related events. Aside from a minor contribution from the neck segment in the direction of travel at preferred and fast walking speeds, regulation of accelerations occurred due to the dynamics of the trunk segment. Inducing neuromuscular fatigue of the cervical and lumbar erector spinae groups (CES and LES) revealed compensatory movement strategies of the upper body, with a view of enhancing head stability. For several variables quantifying attenuation, fatiguing one muscle group, such as the CES, resulted in changes in the dynamics of another level of the upper body, such as the trunk segment. The trunk segment was particularly dominant in regulating upper body accelerations under fatigued conditions, further reinforcing the importance to control accelerations prior to reaching the neck and head. Overall, the results of this study suggest that optimal head stability is reliant on the trunk segment providing a stable base of support for the neck and head. By regulating accelerations via the trunk segment, the postural system is effectively regulating the orientation of the neck and head, and the inclusive sensory organs. It was evident that the postural system prioritises, and in general, maintains head stability during walking despite challenges imposed on upper body stability.

Measuring V02peak is an important health assessment used to indicate cardiorespiratory fitness, prescribe exercise, and diagnose heart abnormalities (2,12). Utilizing the muscles of the upper body, the new StairMaster kayak ergometer is ideal for measuring V02peak on people with lower extremity disorders and those whose occupational or recreational activities rely primarily on the muscles of the upper body (16). Twenty-four healthy college-aged (17-31 years) males and females were screened, gave informed consent, and received orientation to experimental procedures prior to participation in the study. Subjects performed two maximal exercise bouts on the kayak incremental protocol and one on the treadmill incremental protocol. Pearson's r correlation estimated the stability-reliability coefficient of the kayak protocol to be 0.84. Pearson's r correlation estimated the relationship of the kayak protocol to the treadmill protocol to be 0.69. Given performance on the kayak ergometer, the predictive equation for treadmill performance was Y = 11.2605 + 1.02748X (r = 0.48). Body mass index and forearm circumference were found to be adequate predictors of kayak performance using the equation 45.2 - 1.60 BMI + 1.03 Forearm (~ 0.49). Although the kayak incremental protocol demonstrates adequate test-retest reliability for measuring V02peak, it has only a fair relationship to the gold standard of uphill treadmill running. The kayak incremental protocol, therefore, is generally best suited for those who, due to lower extremity complications, are unable to perform traditional modes of testing, or for those whose occupational or recreational activity is dominated by the upper body. / Master of Science

Spinal Cord Injuries (SCIs) are debilitating injuries where damage to the spinal cord causes a loss of mobility and feeling in muscles innervated below the injury point. Tetraplegia refers to an SCI in the cervical region of the spinal cord that impacts on the functionality of all four limbs. ‘Complete’ tetraplegia results in complete paralysis of the legs, partial or complete paralysis of the arms and trunk, and in the most severe cases, the neck. The independence of people living with tetraplegia is heavily dependent on assistive and mobility devices. Understanding the strength characteristics of people with tetraplegia is crucially important for the suitable and effective design of mobility and rehabilitative devices such as wheelchairs. A study using a stationary dynamometer and video capture measured kinetic and kinematic characteristics of wheelchair propulsion for 15 subjects with C5-C7 tetraplegia. This study differentiated between subjects with different injuries, at two different test resistances, and was more comprehensive than other reported studies on MWC propulsion. Some of the subjects in the study with C5-C6 injuries had no elbow extension capability, while others had undergone a deltoids-to-triceps tendon transfer procedure called TROIDS, which restores some elbow extension capability. No differences were found in any of the push phase metrics between those who had undergone the TROIDs procedure, and those who had not, suggesting that TROIDs provides no significant benefit for mobility. As expected, subjects with C7 tetraplegia recorded velocity and power outputs significantly higher than those for subjects with C5-C6 tetraplegia. To better understand the strength characteristics over the full range of motion in the sagittal plane, and thus potentially modify the design of mobility devices to better suit these characteristics, a novel method for gathering strength data in multiple directions and positions was developed. This method had advantages over other commonly used methods. In particular, it was inclusive of complex muscle and joint interactions that would otherwise be very difficult to build into a model. Sagittal horizontal push strength was measured using this method for 8 able bodied and 4 tetraplegic subjects. There were clear trends in the data from the able-bodied subjects, and a fourth order polynomial (R-squared = 0.8) was fitted to the data for modelling purposes. Data for the tetraplegic subjects varied significantly from the able-bodied data, but inter-individual variation was such that no model would provide a satisfactory fit to the data indicating a very high degree of patient-specific behaviour. One multi-directional data set, consisting 1584 measurements in the sagittal plane, was gathered for an able-bodied subject. The main trends in this measured data were successfully captured by a model consisting of twelve fourth-order polynomials. Building on these measurements, and employing a human model in the constraint modelling environment, SWORDS, this thesis develops a conceptual design tool for comparing the effectiveness of different hand force paths. Initial simulations using hypothetical hand paths indicated that the proposed method for predicting the direction of the applied force needs to be verified, and likely refined, for hand paths that differ significantly from the traditional wheelchair push-rim path. This proposed procedure has the potential to be a powerful tool for optimising and modifying the design of wheelchairs or human powered devices to utilise previously untapped abilities for any given population.

A fadiga muscular é um fenômeno extensivamente estudado, especialmente por sua influência sobre o desempenho físico. Diversos estudos têm demonstrado que a acidose muscular, ocasionada pelo acúmulo de íons H+ no interior da célula muscular, é um fator limitante para o desempenho físico durante exercícios físicos de alta intensidade. Assim, estratégias com o objetivo de atenuar a queda do pH intramuscular têm o potêncial de se destacar como agente tamponante. Dentre elas, a suplementação de bicarbonato de sódio tem mostrado ser uma interessante estratégia nutricional para o aumento do desempenho anaeróbio. Recentemente a suplementação de lactato tem se mostrado como um possível agente tamponante. Teoricamente a suplementação de lactato pode aumentar os níveis sanguíneos de pH e bicarbonato, assim aumentando a capacidade tamponante extracelular. Os poucos estudos sugerem um potêncial ergogênico desta estratégia nutricional, embora a falta de estudos sugere a necessidade de mais estudos que atestem a eficácia ergogênica deste suplemento. Portanto, esse estudo tem por objetivo investigar o efeito da suplementação crônica de lactato de cálcio sobre os níveis sanguíneos de pH e bicarbonato e desempenho intermitente de alta intensidade; e ainda, compará-los com a suplementação de bicarbonato de sódio. Foram recrutados 18 atletas (idade 26 ± 5 anos; massa corporal 88,8 ± 6,8 kg; estatura 1,78 ± 0,7m; gordura corporal 18,6 ± 6,2 %). A pesquisa teve um desenho randomizado, controlado por placebo, duplo-cego cross-over. Os sujeitos foram alocados em 3 tratamentos diferentes: placebo, lactato de cálcio e bicarbonato de sódio. Todos os tratamentos suplementaram a dose de 500 mg.kg-1, divididas em 4 doses diárias, por um período de cinco dias consecutivos, seguido por dois dias de washout. Os indivíduos foram submetidos a testes de desempenho físico anaeróbio para membros superiores. Foram realizadas 4 séries do teste de Wingate, com duração de 30 segundos em cada série, e carga fixa em 4% do peso corporal, separadas por períodos de recuperação ativa de 3 minutos. As variáveis de potência média, pico e trabalho total, foram usados para verificação de alterações no desempenho em virtude dos tratamentos. Foi ainda avaliado os níveis sanguíneos de pH, bicarbonato e lactato no repouso, após o esforço e 5min após o esforço. A análise de reprodutibilidade do teste de Wingate mostrou que não houve diferenças entre as duas familiarizações e o teste pré-suplementação. As variáveis sanguíneas não foram diferentes entre os testes, e evidenciaram o potêncial do teste em diminuir pH, bicarbonato e excesso ácido-base e aumentar o lactato plasmático. Os resultados mostram que a suplementação de lactato de cálcio não foi capaz de melhorar o desempenho ou influenciar variáveis sanguíneas de bicarbonato e pH, no entanto a suplementação de bicarbonato de sódio melhorou o desempenho em ~2,9% e aumentou os níveis basais de bicarbonato sanguíneo, mas não alterou o pH. Dessa forma conclui-se que tal estratégia não é capaz de aumentar a capacidade tamponante, tampouco de promover melhoras no desempenho intermitente de alta intensidade / Muscle fatigue is an extensively studied phenomenon, especially due to its relevance to performance. Several studies have shown that muscle acidosis caused by hydrogen ion (H+) accumulation in the muscle cell is a limiting factor to physical performance during high-intensity exercise. Thus, strategies aimed at attenuating the fall in intramuscular pH during exercise have the potential to improve performance. Among these strategies, sodium bicarbonate supplementation has been shown to be an effective nutritional strategy for increasing anaerobic performance. Recently, lactate supplementation has been suggested to be an equally effective buffering aid. Theoretically, lactate supplementation can increase blood pH and bicarbonate levels, thereby increasing extracellular buffering capacity. The few studies available to date have shown the ergogenic potential of this nutritional strategy, although the lack of studies with chronic supplementation in addition to the lack of reliable physical tests suggests the need for more studies to confirm the efficacy of lactate supplementation. Therefore, this study aimed to investigate the effect of chronic calcium lactate and sodium bicarbonate supplementation on blood pH, bicarbonate and high-intensity intermittent exercise performance. Eighteen athletes (age 26±5 years; body mass 88,8±6,8 kg; height 1,78± 0,7m; body fat 18,6±6,2 %) were recruited to this randomised, double-blind, placebo-controlled, crossover and counterbalanced study. The participants\' underwent 3 different treatments: placebo, calcium lactate and sodium bicarbonate. The dose in all conditions was 500 mg·kg-1, divided into 4 daily doses, for 5 consecutive days, followed by a 2-day washout period. On the fifth day of supplementation, individuals underwent 4 bouts of the Wingate upper-body anaerobic test. The bouts lasted 30 seconds, with a fixed load of 4% body mass and were separated by active recovery periods of 3 minutes. Mean and peak power, as well as total work done, were recorded during each bout. In addition, blood pH, bicarbonate and lactate were determined at rest, immediately after exercise and 5 min after exercise. The Wingate test reproducibility analysis showed no differences between both familiarisations and a pre-supplementation test while blood variables were not different between tests. Post-exercise values highlighted the potential of the test to decrease blood pH, bicarbonate and base excess and to increase plasma lactate. Results showed that calcium lactate supplementation did not improve upper-body Wingate performance, likely due to a lack of change in blood bicarbonate and pH prior to exercise. Sodium bicarbonate supplementation improved performance by ~2.9% following increased pre-exercise levels of blood bicarbonate but not pH. It can be concluded that calcium lactate supplementation is not capable of increasing buffering capacity, and thus does not promote improvements in high-intensity intermittent performance

With the recent developments in Computer Vision and Pattern Recognition, surveillance applications are equipped with the capabilities of event/activity understanding and interpretation which usually require recognizing humans in real world scenes. Real world scenes such as airports, streets and train stations are complex because they involve many people, complicated occlusions and cluttered backgrounds. Although complex real world scenes exist, human detectors have the capability to locate pedestrians accurately even in complex scenes and visual trackers have the capability to track targets in cluttered environments. The integration of visual object detection and tracking, which are the fundamental features of available surveillance applications, is one of the solutions for multi-human tracking problem in crowded scenes which is studied in this thesis. In this thesis, human body part detectors, which are capable of detecting human heads and human upper body parts, are trained with Support Vector Machines (SVM) by using Histogram of Oriented Gradients (HOG), which is one of the state-of-the-art descriptor for human detection. The training process is elaborated by investigating the effects of the parameters of the HOG descriptor. The human heads and upper body parts are searched in the region of interests (ROI) computed by detecting motion. In addition, these human body part detectors are integrated with a multi-human tracker which solves the data association problem with the Multi Scan Markov Chain Monte Carlo Data Association (MCMCDA) algorithm. Associated measurements of human upper body part locations are used for state correction for each track. State estimation is done through Kalman Filter. The performance of detectors are evaluated using MIT Pedestrian dataset and INRIA Human dataset.

A fadiga muscular é um fenômeno extensivamente estudado, especialmente por sua influência sobre o desempenho físico. Diversos estudos têm demonstrado que a acidose muscular, ocasionada pelo acúmulo de íons H+ no interior da célula muscular, é um fator limitante para o desempenho físico durante exercícios físicos de alta intensidade. Assim, estratégias com o objetivo de atenuar a queda do pH intramuscular têm o potêncial de se destacar como agente tamponante. Dentre elas, a suplementação de bicarbonato de sódio tem mostrado ser uma interessante estratégia nutricional para o aumento do desempenho anaeróbio. Recentemente a suplementação de lactato tem se mostrado como um possível agente tamponante. Teoricamente a suplementação de lactato pode aumentar os níveis sanguíneos de pH e bicarbonato, assim aumentando a capacidade tamponante extracelular. Os poucos estudos sugerem um potêncial ergogênico desta estratégia nutricional, embora a falta de estudos sugere a necessidade de mais estudos que atestem a eficácia ergogênica deste suplemento. Portanto, esse estudo tem por objetivo investigar o efeito da suplementação crônica de lactato de cálcio sobre os níveis sanguíneos de pH e bicarbonato e desempenho intermitente de alta intensidade; e ainda, compará-los com a suplementação de bicarbonato de sódio. Foram recrutados 18 atletas (idade 26 ± 5 anos; massa corporal 88,8 ± 6,8 kg; estatura 1,78 ± 0,7m; gordura corporal 18,6 ± 6,2 %). A pesquisa teve um desenho randomizado, controlado por placebo, duplo-cego cross-over. Os sujeitos foram alocados em 3 tratamentos diferentes: placebo, lactato de cálcio e bicarbonato de sódio. Todos os tratamentos suplementaram a dose de 500 mg.kg-1, divididas em 4 doses diárias, por um período de cinco dias consecutivos, seguido por dois dias de washout. Os indivíduos foram submetidos a testes de desempenho físico anaeróbio para membros superiores. Foram realizadas 4 séries do teste de Wingate, com duração de 30 segundos em cada série, e carga fixa em 4% do peso corporal, separadas por períodos de recuperação ativa de 3 minutos. As variáveis de potência média, pico e trabalho total, foram usados para verificação de alterações no desempenho em virtude dos tratamentos. Foi ainda avaliado os níveis sanguíneos de pH, bicarbonato e lactato no repouso, após o esforço e 5min após o esforço. A análise de reprodutibilidade do teste de Wingate mostrou que não houve diferenças entre as duas familiarizações e o teste pré-suplementação. As variáveis sanguíneas não foram diferentes entre os testes, e evidenciaram o potêncial do teste em diminuir pH, bicarbonato e excesso ácido-base e aumentar o lactato plasmático. Os resultados mostram que a suplementação de lactato de cálcio não foi capaz de melhorar o desempenho ou influenciar variáveis sanguíneas de bicarbonato e pH, no entanto a suplementação de bicarbonato de sódio melhorou o desempenho em ~2,9% e aumentou os níveis basais de bicarbonato sanguíneo, mas não alterou o pH. Dessa forma conclui-se que tal estratégia não é capaz de aumentar a capacidade tamponante, tampouco de promover melhoras no desempenho intermitente de alta intensidade / Muscle fatigue is an extensively studied phenomenon, especially due to its relevance to performance. Several studies have shown that muscle acidosis caused by hydrogen ion (H+) accumulation in the muscle cell is a limiting factor to physical performance during high-intensity exercise. Thus, strategies aimed at attenuating the fall in intramuscular pH during exercise have the potential to improve performance. Among these strategies, sodium bicarbonate supplementation has been shown to be an effective nutritional strategy for increasing anaerobic performance. Recently, lactate supplementation has been suggested to be an equally effective buffering aid. Theoretically, lactate supplementation can increase blood pH and bicarbonate levels, thereby increasing extracellular buffering capacity. The few studies available to date have shown the ergogenic potential of this nutritional strategy, although the lack of studies with chronic supplementation in addition to the lack of reliable physical tests suggests the need for more studies to confirm the efficacy of lactate supplementation. Therefore, this study aimed to investigate the effect of chronic calcium lactate and sodium bicarbonate supplementation on blood pH, bicarbonate and high-intensity intermittent exercise performance. Eighteen athletes (age 26±5 years; body mass 88,8±6,8 kg; height 1,78± 0,7m; body fat 18,6±6,2 %) were recruited to this randomised, double-blind, placebo-controlled, crossover and counterbalanced study. The participants\' underwent 3 different treatments: placebo, calcium lactate and sodium bicarbonate. The dose in all conditions was 500 mg·kg-1, divided into 4 daily doses, for 5 consecutive days, followed by a 2-day washout period. On the fifth day of supplementation, individuals underwent 4 bouts of the Wingate upper-body anaerobic test. The bouts lasted 30 seconds, with a fixed load of 4% body mass and were separated by active recovery periods of 3 minutes. Mean and peak power, as well as total work done, were recorded during each bout. In addition, blood pH, bicarbonate and lactate were determined at rest, immediately after exercise and 5 min after exercise. The Wingate test reproducibility analysis showed no differences between both familiarisations and a pre-supplementation test while blood variables were not different between tests. Post-exercise values highlighted the potential of the test to decrease blood pH, bicarbonate and base excess and to increase plasma lactate. Results showed that calcium lactate supplementation did not improve upper-body Wingate performance, likely due to a lack of change in blood bicarbonate and pH prior to exercise. Sodium bicarbonate supplementation improved performance by ~2.9% following increased pre-exercise levels of blood bicarbonate but not pH. It can be concluded that calcium lactate supplementation is not capable of increasing buffering capacity, and thus does not promote improvements in high-intensity intermittent performance

Concurrent training (CT) is defined as the development of both endurance and strength within the same exercise program. CT has been studied for decades, but the results has been diverse. However, very few have studied the effects of CT on the upper body musculature. Hence, this review set out to investigate the effects of combined strength and endurance training (ET) of the upper body on muscle hypertrophy, muscle strength and endurance variables. PubMed was searched with relevant search terms with varying combinations, such as concurrent training, combined strength and endurance training. After scanning the literature, a total of eight articles were included. The results suggest that muscle strength, exercise economy and time to exhaustion can effectively be improved by CT of the upper body. The effect of CT on upper body musculature were unclear. Some of the articles included suggests a decrease in whole body lean mass, which might simply be due to insufficient loading of the lower body musculature. In order to maintain muscle mass during a CT protocol, endurance athletes should aim to perform ST which targets muscles active during ET. However, the limited empiric literature available on CT of the upper body makes a conclusion hard to draw. This review shows that CT of the upper body is yet an unexplored and researchers should further investigate the effects of CT for the musculature of the upper body alone. If we gain more knowledge of the effects from concurrent training of the upper body, it could have several implications, both clinically and in a sport setting.

No description available.

No description available.