The project focus has been development of guidelines and methods for upper extremity injury reduction in car crashes. The safety of the central body parts improves which indicates the need to develop methods for avoiding non-life threatening injuries such as fracture of the arms. The purpose of the project was to study the injury mechanisms for the upper extremity in car crashes, and the aim has been to propose methods to reduce the injuries. The project focuses on adult occupants inside the vehicles front seat, and frontal and side impacts. The procedure began with understanding and identifying the injury mechanisms. Studies show that most fractures occur on the forearm (radius and ulna) and on the wrists and hands. To determine which injury mechanisms that were most frequent, data were collected from 29 computer simulations with 29 different crash scenarios. The most common kind of impact was the medial part of the wrist in the central part of the instrument panel, combined with the impact of the elbow in the center consol. The results of the simulations created a basis for the method of the component test, with focus on the injury mechanism i.e. the forward movement of the arms into the instrument panel. The component test consisted of a test rig, on which was mounted with a measuring arm of a 50th percentile male dummy. The arm dropped into a block of expanded polypropylene (EPP-block) for observation and study, and with following variable parameters: the impact angle of the surface, velocity and position of the wrist. Then also an instrumented measuring arm from a 5th percentile female dummy was released into an instrument panel. The project contributes to knowledge about the injury mechanism of the upper extremity in car crashes. The most frequent injury mechanism is a forward movement of the arms resulting in an impact with the interior structure of the car. The most frequent injured region is the distal part of the upper extremity. The project has developed and suggested the first step to a test method for the specific injury mechanism. There is a need of more research on how impact angles and velocity affect the violence on the arm.

ABSTRACT Common lower extremity injuries in female high school soccer players in Johannesburg east district Mtshali P.T.S. Background and purpose of research As the number of females participating in sports has increased, so has the necessity of understanding the effect of female growth and development in participation, athletic ability and injury patterns. Soccer is one of the sports where South Africa has seen an increase of youth and adult females’ participation. Aim: To establish the prevalence of and extrinsic risk factors contributing to injuries in the lower extremity in female high school soccer players in the Johannesburg east district. Method: A retrospective descriptive questionnaire – based study of 103 first team high school female soccer players in the Johannesburg east district was conducted. This was to determine point and one year prevalence of injuries, profile of injuries that affect female soccer players, associations between injuries and player position, age, use of equipment, frequency of play, and training duration and also to identify possible risk factors that contribute to injuries. Results: The one year prevalence of injured players was 46.1% and point prevalence was 37.8%. Knee injuries (18.6%) and ankle injuries (17.6%) were reported for one year prevalence and for point prevalence knee injuries were 13.3% and ankle injuries 18.9%. An extended duration of skills (p=0.0001) and fitness (p=0.02) training in this population reduced the likelihood of incurring an injury and the older (p=0.01) the players, the more chances of sustaining injuries. The players who wore shin guards were less prone to shin/leg injuries (p=0.01) and the relative odds were 0.35 (CI 0.16-0.79). The midfielders had more foot and toe injuries (p = 0.05). Starting age (p=0.78), frequency of play (p=0.83) wearing of shoes (p=0.54) and stretching had no influence on injury. Conclusion: The knee and ankle were the main locations of injury with defenders and midfielders mostly being injured. The increased duration of training for both skills and fitness and not wearing shin guards are risk factors for injury in female soccer players in high school.

Every year, millions of people are killed or injured in motor vehicle accidents in the United States. Although recent improvements to occupant restraint systems, such as seatbelts and airbags, have significantly decreased life threatening injuries, which usually occur to the chest or head, they have done little to decrease the occurrence of lower extremity injuries. Although lower extremity injuries are not usually life threatening, they can result in chronic disability and high psychosocial cost. Of all lower extremity injuries, injuries to the knee-thigh-hip (KTH) region have been shown to be among the most debilitating. This project used a finite element (FE) model of the KTH region to study injury. A parametric investigation was conducted where the FE KTH was simulated as a vehicle occupant positioned to a range of pre-crash driving postures. The results indicate that foot contact force and knee kinematics during impact affects the axial force absorbed by the KTH region and the likelihood of injury. The results of the study could be used to reevaluate the lower extremity injury thresholds currently used to regulate vehicle safety standards. Also, the results could be used to provide guidelines to vehicle manufacturers for developing safer occupant compartments.

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Este estudo teve como objetivo implementar um modelo biomecânico, de segmentos articulados, associado à solução inversa que permita a análise em três dimensões das forças de reação proximais e momentos proximais resultantes para diferentes gestos do membro superior. O modelo implementado é composto por cinco segmentos rígidos (mão, antebraço, braço, escápula e tronco) conectados. A resolução das equações de movimento de Newton-Euler é feita através da solução inversa. Para registro cinemático foram utilizadas cinco câmeras digitais, com freqüência de amostragem de 50 campos/seg. O modelo implementado foi avaliado de quatro formas: estimativa da acurácia da medida tridimensional obtida pela cinemetria, comparação quantitativa e qualitativa dos resultados parciais oferecidos pelo modelo implementado com resultados obtidos por instrumentos de mensuração direta (eletrogoniômetro e eletromiografia) e cálculo da propagação do erro nos valores de força de reação resultante e momento proximal líquido. Os resultados sugerem que o modelo apresenta resultados coerentes. A acurácia do sistema de videogrametria estimada foi, em média, de 1,7 (± 1,5) mm. As medidas angulares da cinemetria e eletrogoniometria divergiram em até 36°. O erro propagado no cálculo da força de reação proximal pode chegar até 25% e até 100% no cálculo do momento proximal. O sinal eletromiográfico e o momento proximal apresentaram sincronismo temporal. O modelo foi capaz de avaliar as forças de reação proximal resultantes e momentos proximais líquidos nos diferentes gestos. / The goal of this study was to implement a link segments biomechanical model, associate to the inverse solution for three dimensions analysis of proximal reaction force and proximal net moments during upper limb movement. The implemented model is composed by five connected rigid segments (hand, forearm, arm, scapula and trunk). The resolution of Newton-Euler movement equations is done through the inverse solution. For kinematics acquisition five digital cameras were used, with a frequency sample of 50 fields/sec. The implemented model was evaluated in four ways: accuracy estimation of the three-dimensional measurements, quantitative and qualitative comparison of the partial results offered by the implemented model with results obtained by instruments of direct measurements (electrogoniometer and electromyography) and calculation of the error propagation in proximal reaction force and proximal net moment values. The results suggest that the model presents coherent results. The estimated accuracy videogrammetry system was, on average, of 1.7 (± 1.5) mm. The joint angular values obtained by kinematics system and electrogoniometer diverged in 36°. The error propagation in proximal reaction force values can arrive up to 25% and up to 100% for proximal net moment. The electromyographic sign and the proximal moment presented temporary synchronism. The model was able to evaluate the proximal reaction force and proximal net moment during upper limb movement.

Differences in gait biomechanics have been observed between obese and healthy weight adults. It is possible that body segment parameters, particularly the thigh, contribute to the differences in knee biomechanics observed during gait between obese and healthy weight adults. The purpose of this study was to determine if increases in thigh circumference and/or mass associated with obesity alter walking biomechanics in healthy weight males and females. Thigh mass and circumference were increased proportional to a 10 unit increase in body mass index. Frontal and sagittal plane knee angles and moments, and temporospatial variables were recorded. For all dependent variables no main effect for gender was observed. Peak knee flexion angle was similar across conditions with no interaction. There was an interaction for peak internal knee extension moment however post hoc comparisons did not reveal differences in condition among males or females. A main effect for condition was observed for peak knee adduction angle, however post hoc comparisons did not reveal differences among conditions. Peak internal knee abduction moment was similar across conditions with no interaction. Stance time and step width increased during the experimental conditions compared to the control. A interaction was observed for stance time. Females had a longer stance time during the circumference only condition compared to the control condition. A greater step width was observed in conditions that increased thigh circumference. Overall, thigh segment parameters altered gait temporospatial variables. Increases in stance time and step width in obese adults compared to healthy weight adults could be a result of their larger thigh segment parameters.

The Strain Index (SI) has repeatedly shown high levels of validity for differentiating between safe and hazardous tasks for the distal upper extremity (DUE). One limitation of the SI is the lack of reliability data. This study was designed to evaluate the test-retest repeatability of the SI. Fifteen raters, divided into five teams of three, were asked to use the SI to analyze 73 video AVI files of different job tasks; initially as individuals and then as teams. Several months later, raters were asked to repeat individual and team job task assessments. Raters were instructed to analyze tasks using five of six SI task variables, while the sixth was held constant. For three of these task variables, additional data was collected such as peak force and duration of job cycle. Test-retest repeatability was measured using Pearson's R, Spearman's rho, and tetrachoric correlation according to the nature of the variable. Spearman's rho values for individual and team task variable ratings ranged from 0.68 to 0.96 (0.88 average). Pearson's R for task variable data ranged from 0.76 to 0.99 for both teams and individuals with an average of 0.91. The Strain Index's rho values for individuals and teams were 0.70 and 0.84, respectively. For hazard classification, the tetrachoric correlation for individuals was 0.81 and 0.88 for teams. Results of this study support the conclusion that the Strain Index is repeatable when used by teams as well as individuals.

The main objective of my dissertation was to evaluate the biomedical and psychosocial factors associated with pain and disability in patients following traumatic upper extremity nerve injuries. This was approached by conducting 3 studies. The first study surveyed peripheral nerve surgeons regarding the assessment of pain in patients with nerve injury. The results showed that only 52% of surgeons always evaluate pain in patients referred for motor/sensory dysfunction. Pain assessment frequently includes verbal response and assessment of psychosocial factors is infrequent. The second study was a retrospective review to assess disability, as measured by the Disabilities of the Arm, Shoulder and Hand (DASH), in patients with chronic nerve injury. Results showed substantial disability (mean DASH 52 + 22) and a significantly lower health status (p < 0.001) compared with well-established norms. In the regression model, the factors associated with the DASH (R2 = 44.5%) were pain, older age and nerve injured. The third study was a cross-sectional evaluation of the biomedical and psychosocial factors associated with pain and disability after upper extremity nerve injury in 158 patients. DASH scores were significantly higher in patients with workers’ compensation or litigation (p = 0.03), brachial plexus injuries (p < 0.001) and unemployed patients (p < 0.001). In the multivariable regression analysis, the final model explained 52.7% of the variance with these predictors; pain intensity (Beta = .230, p = 0.006), nerve injured (Beta = -.220, p = 0.000), time since injury (Beta = -.198, p = 0.002), pain catastrophizing (Beta = .192, p = 0.025), age (Beta = .187, p = 0.002), work status (Beta = .179, p = 0.008), cold sensitivity (Beta = .171, p = 0.015), depression score (Beta = .133, p = 0.066), workers’ compensation/litigation (Beta = .116, p = 0.049) and gender (Beta = -.104, p = 0.09). Future investigation regarding treatments of the factors that are associated with disability and chronic pain will assist to improve health related quality of life in patients with traumatic nerve injury.

The main objective of my dissertation was to evaluate the biomedical and psychosocial factors associated with pain and disability in patients following traumatic upper extremity nerve injuries. This was approached by conducting 3 studies. The first study surveyed peripheral nerve surgeons regarding the assessment of pain in patients with nerve injury. The results showed that only 52% of surgeons always evaluate pain in patients referred for motor/sensory dysfunction. Pain assessment frequently includes verbal response and assessment of psychosocial factors is infrequent. The second study was a retrospective review to assess disability, as measured by the Disabilities of the Arm, Shoulder and Hand (DASH), in patients with chronic nerve injury. Results showed substantial disability (mean DASH 52 + 22) and a significantly lower health status (p < 0.001) compared with well-established norms. In the regression model, the factors associated with the DASH (R2 = 44.5%) were pain, older age and nerve injured. The third study was a cross-sectional evaluation of the biomedical and psychosocial factors associated with pain and disability after upper extremity nerve injury in 158 patients. DASH scores were significantly higher in patients with workers’ compensation or litigation (p = 0.03), brachial plexus injuries (p < 0.001) and unemployed patients (p < 0.001). In the multivariable regression analysis, the final model explained 52.7% of the variance with these predictors; pain intensity (Beta = .230, p = 0.006), nerve injured (Beta = -.220, p = 0.000), time since injury (Beta = -.198, p = 0.002), pain catastrophizing (Beta = .192, p = 0.025), age (Beta = .187, p = 0.002), work status (Beta = .179, p = 0.008), cold sensitivity (Beta = .171, p = 0.015), depression score (Beta = .133, p = 0.066), workers’ compensation/litigation (Beta = .116, p = 0.049) and gender (Beta = -.104, p = 0.09). Future investigation regarding treatments of the factors that are associated with disability and chronic pain will assist to improve health related quality of life in patients with traumatic nerve injury.

The high strength, light weight, and flexibility of fabric protection systems makes them the preferred solution for a number of ballistic applications. Examples include body armor, fan blade containment for jet engines, and orbital debris shielding. In general, these protection systems employ plain woven fabric, most suitable for flat or gently curved geometries. Highly curved surfaces, such as personnel extremities, may be more effectively protected using fabrics of different weaves. This dissertation presents the first numerical model developed to simulate ballistic impacts into plain, harness satin, twill, and basket weave fabrics. It extends previous work on hybrid particle-finite element methods developed for fabric modeling. The extended formulation closely replicates the tensile load response and contact-impact dynamics of highly flexible yarns, by generalizing the kinematic model and density interpolation used in previous work. The formulation has been validated in three dimensional simulations of impact experiments conducted to investigate the effects of weave type on fabric ballistic performance. / text