Myocardial infarctions induce a maladaptive ventricular remodeling process that independently contributes to heart failure. In order to develop effective treatments, it is necessary to understand the way and extent to which the heart undergoes remodeling over the course of healing. There have been few studies to produce any data on the in-vivo material properties of infarcts, and much less on the properties over the time course of healing. In this paper, the in-vivo passive material properties of an infarcted porcine model were estimated through a combined use of magnetic resonance imaging, catheterization, finite element modeling, and a genetic algorithm optimization scheme. The collagen fiber orientation at the epicardial and endocardial surfaces of the infarct were included in the optimization. Data from porcine hearts (N=6) were taken at various time points after infarction, specifically 1 week, 4 weeks, and 8 weeks post-MI. The optimized results shared similarities with previous studies. In particular, the infarcted region was shown to dramatically increase in stiffness at 1 week post-MI. There was also evidence of a subsequent softening of the infarcted region at later time points post infarction. Fiber orientation results varied greatly but showed a shift toward a more circumferential orientation.

The use of knee braces prophylactically is still considered as an approach for injury mitigation for those in high-risk sporting activities, though their use is not fully supported. The purpose of this thesis was to examine biomechanical and neuromuscular effects of prophylactic brace wear following standardized repetitive exercise. Twelve participants participated and acted as their own control. The participants were required to participate in two sessions, one control session with no brace and one intervention session with the application of a off-the-shelf prophylactic knee brace. Pre-and post-exercise intervention single leg drop landings were recorded to examine the effects of an acute exercise stimulus on the neuromuscular and biomechanical effects of brace wear. Additionally, trials were collected at 30-minutes post-exercise to examine residual effects of the brace wear on landing kinematics and kinetics. Difference tests using analysis of variance (ANOVA) showed that there was a minimal effect of the prophylactic knee brace on biomechanical and neuromuscular variables following exercise as well as 30-minutes following knee brace removal. Further research may be required to identify if braces can be worn prophylactically to reduce the risk of injury during activity.

Background: The incidence of injuries in rugby union has increased on both professional and amateur levels since the introduction of professionalism in 1995. Although rugby union is a body contact sport with an expected high injury rate, limited research has been done regarding the postural and biomechanical characteristics of the players and the effect these variables have on the incidence and nature of rugby union injuries. Large body size is a significant predictor of success in rugby union and the body mass and mesomorphy of players has increased over the last years. It has, however, not been thoroughly investigated whether changes in body composition have any effect on the incidence of rugby union injuries. Intrinsic risk factors that have been identified to contribute to rugby union injuries are Hyper-mobility of joints, lack of dynamic mobility and core stability, previous injuries, aerobic and anaerobic fitness as well as the personalities and characteristics of players which affect their on-field awareness. The findings of studies investigating the relation between player characteristics and rugby union injuries are inconsistent because of the differences in player characteristics under investigation and playing conditions, different research methodologies used as well as differences in the way injury is defined. Therefore, the need exists to determine the differences in the biomechanical, postural and anthropometrical characteristics of injured and uninjured rugby union players by making use of a prospective design and a standardized injury definition. Objectives: The objectives of this study were firstly, to determine the incidence and nature of injuries among U/21 rugby union players at the Rugby Institute (RI) of the North-West University (NWU) (South Africa) and secondly, to determine which of the selected biomechanical, postural and anthropometrical characteristics contributed to musculoskeletal injuries obtained during the first five months of the 2005 season. Method: s A prospective once-off subject availability study was performed that included forty-nine U/21-rugby union players of the RI of the NWU. Biomechanical, postural and anthropometrical assessments were performed on all subjects before the start of the 2005- season. All the injuries sustained during the first five months of the 2005 season were recorded by means of a validated rugby union injury report questionnaire. A stepwise discriminant analysis identified the independent variables that discriminated mostly between the players with and without injuries within the different body regions. Back-classification by means of the "Jack-knife method" determined whether the independent characteristics that were selected to contribute to injuries was valid and the effect size, I ("better than chance"), was then determined, with I > 0.3 accepted as practically significant. Results: A total of 66 injuries with an injury rate of 8.611000 training hours and 61.811000 game hours were reported. Severe injuries accounted for 53% of all injuries to forward players with the ankle being the most injured anatomical region. In the backline severe injuries accounted for 11% with the shoulder being the most injured region. The tackle was the phase of play in which most injuries occurred. The statistical analysis identified uneven hips, pronated feet, tight hamstrings, anatomical leg length differences, gait pronation and a tall stature to be practically significant predictors for lower extremity injuries (I>0.3). No practical significance was obtained for the selected biomechanical, postural and anthropometrical characteristics related to shoulder girdle as well as back or spine injuries. Conclusions: The conclusions that can be drawn from this study are that the injury incidence of rugby union players of the U/21-squad of the RI of the NWU is high in comparison with those of other club level players and that postural and biomechanical imbalances of the lower extremities may increase the risk for injury in this area. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2007.

The primary aim of this study was to evaluate the effectiveness of an injury prevention and training programme for elite cricketers in regard to biomechanical, physical and motor and anthropometric variables over a period of six cricketing off-seasons (1998/1999-2003/2004). A secondary aim was to investigate the injury epidemiology of elite cricket players over a six-season period (1998/1999 – 2003/2004). A total of 93 cricket players, who were part of the North-West professional cricket squad, were evaluated over a six-season period stretching from the 1998/1999 cricket season to 2003/2004 cricket season. The players were all evaluated at the end of the off-season (middle September) of the commencing season and the injury lists were compiled throughout each playing season. This included all players who needed medical attention due to injury sustained while representing the North-West cricket team in a cricket match. An analysis was done of literature sources by making use of electronic media, library search and sports medicine journals. Databases such as Pubmed, EbscoHost (Academic Search Elite), Sciencedirect, Medline, Eric, Health Source - Consumer Edition, Health Source: Nursing/Academic Edition and SPORTDiscus were used. Special consideration was given to cricket injury epidemiology, injury prevention strategies in cricket, biomechanics in cricket and general injury prevention strategies. The recorded data were statistically processed and the practical significances were calculated. Three different protocols were followed to evaluate the effectiveness of the injury prevention and training programme. The recorded data were analysed for the six off-season periods (1998/1999-2003/2004, protocol 1) of the study for the biomechanical, physical and motor and anthropometric evaluations, as well as for the injury epidemiology. The players were then divided into four exposure times (protocol 2) in the study for the biomechanical, physical and motor and anthropometric evaluations. Then the players were divided into two groups (protocol 3), with each group consisting of the same players, and over a three off-season period each evaluated for the biomechanical, physical and motor and anthropometric variables. Lastly, the results for the last three seasons of protocol 1 were compared with the result of the last three seasons of protocol 3 (group 2) for the biomechanical, physical and motor and anthropometric evaluations, as well as for the injury epidemiology. The results for this study indicate that the injury prevention and training programme was successful in improving and maintaining the biomechanical, physical and motor and anthropometric profile of the cricketers over the six off-season periods (1998/1999-2003/2004). Although all injuries could not be prevented, injuries resulting from structural vulnerability did decrease. Injuries resulting from structural vulnerability (mechanism of injury) decreased from the 1998/1999 season (67,67% of the total injuries suffered during the 1998/1999 season) to the 2003/2004 season (10% of the total injuries suffered during the 2003/2004 season), indicating that the training and prevention programme played a role in the prevention of these injuries. Injury incidence per 10 000 hours of play was 5,82 injuries for the six-season period (1998/1999- 2003/2004). The injury prevention and training programme used in this study can be utilised to improve the biomechanical, physical and motor and anthropometric profile of cricketers. The biomechanical, physical and motor and anthropometric evaluations can also be used as injury prevention strategies by identifying possible injury risk factors as a result of poor biomechanical, physical and motor and anthropometric profiles. / Thesis (Ph.D. (Education))--North-West University, Potchefstroom Campus, 2005.

Background: The multiplicities of factors, which may contribute to injury from sporting activity, and the complexity of the relations among them, indicate that identifying causal mechanisms poses a challenge to epidemiologists. The identification of risk factors associated with the effect of the injury on subsequent participation may be as important in understanding how to reduce the burden of injuries on sports participants, as identifying factors associated with the injury incidence rate. Aim: The aim of this study was to develop a biomechanical, antbropometrical, physical, motor and injury epidemiology profile for elite U/19 rugby players. Design: A prospective cohort study. Subiects: In this study 77 elite rugby players were used during the first testing episode (October 2005). These players had just completed their school career and were selected to form part of the Rugby Institute of the University of North West. The U/19 first team members were (n = 31) tested again in July 2006. Two different profiles were established. Method: Once approval had been granted by both the players and by the Rugby Institute of the North West University, the players were submitted to a test battery. Anthropometric, Physical and Motor tests were done at the beginning of the season and the players re-tested at the end of the season. A Biomechanical and Postural Evaluation was done once-off at the beginning of the season. The necessary steps were taken to address existing shortcomings identified in the test subjects. After the results had been analysed, individual programmes were formulated, explained and implemented. The aim was to minimize the possible risk areas indicated by screening. Results: The results were statistically processed, recorded and compared with previous literature studies, according to both the total group and the different player positions - these are the tight five, the loose forwards, the halfbacks and the backs. The Anthropometrical, Physical and Motor testings showed a low or nil practical significant difference for the total group after a season of professional training and coaching, with slight differences between the player groups. The Biomechanical and Postural Evaluation proved the group to be dynamically overloaded with poor regional stability and musculature as far as the upper and lower limbs were concerned, with asymmetry and weak core stability of the spinal and pelvic region. A total of 184 injuries were reported over the season, with the lower limbs (58%) and upper limbs (23%) as the most commonly injured body parts; and sprains (22%) and strains (17%) the type of injury which occurred most often. The tight five (32%) had the highest injury rate, with the flanker (13%) the least injured player position. Conclusion: A profile for elite U/19 rugby players has been determined. This profile can be implemented in conjunction with similar findings in existing literature for future guidelines by coaches and the management to select a better team, to ensure a higher quality of performance and to prevent injuries. / Thesis (M.Ed.)--North-West University, Potchefstroom Campus, 2007.

Injuries in the female gymnast are common and it is important to understand the biomechanical factors responsible for injury. The Back Walkover maneuver requires one of the greatest amounts of lumbar hyperextension compared to other common gymnastic maneuvers. During the Back Walkover large lateral and vertical impact forces follows on the spine. The spine and muscles around the spine have to absorb generally large forces; therefore the loads on the back and certainly on the lower back are of significant interest. Additionally, it takes a lot of strength and a vast range of motion to perform gymnastic maneuvers such as The Back Walkover. It is of interest to study mechanical loads on a female gymnast since they show higher occurrences of stress-related pathologies of the lumbar spine. Therefore the purpose of this project was to examine the loads on the spine during the gymnastic maneuver Back Walkover. Tests on a single female gymnast were made at the sports engineering lab at the University of Adelaide in Australia. Using the 3D-camera system; Optitrack Motion Capture System and Kistler Force Plate, positional data for two dimensions, X-direction (anterior-posterior) and Z-direction (vertical), and ground force were received. Data received were progressed into a graph, diagrams and biomechanical calculations where forces for the vertebrae L1 were calculated in vertical and horizontal direction. The received forces were compared to vertical and horizontal forces in L1 during standing position. Together with developed videos this assisted to model the loads of the spine (L1) during the gymnastic maneuver the “Back Walkover”. The study has led to a deeper knowledge for the community about the risks for female gymnasts and has widened the experience of the project participant, as the project aimed.

This project presented a biomechanical model of the lumbosacral spine and pelvis, including novel methodologies associated with the measurement of human mechanics. This research has, for the first time, produced accurate three-dimensional geometric models of the human skeleton from living subjects using magnetic resonance imaging technology, enabling the prediction of physiological muscle action within individuals. The model was used to examine changes in the mechanics of the lumbopelvic musculoskeletal system between the standing and seated postures due to the increasing prevalence of the seated posture in the work and home environment. The outcomes of this research included a novel bone wrapping algorithm used to describe the effect of muscle-bone interactions. a novel method for creating three-dimensional in vivo spinal reconstructions using MRI, three dimensional in vivo helical axis measurements and subject specific normalised moment data.

No description available.

Remote area staff performing manual patient handling tasks in the absence of patient lifting hoists available in most health care settings are at an elevated risk of musculoskeletal injuries. The objective of this project was to identify the patient handling methods that have the lowest risk of injury. The patient handling task of lifting a patient from floor to a chair or wheelchair is a common task performed in a remote health care setting. The task was performed utilising three methods, these being: (1) heads/tails lift, (2) use of two Blue MEDesign?? slings and (3) use of a drawsheet. The task of the heads/tails lift was broken down into two distinctly separate subtasks: lifting from the (1) head and (2) tail ends of the patient load. These techniques were selected based on criteria including current practice, durability, portability, accessibility, ease of storage and cost to supply. Postural data were obtained using a Vicon 370 three - dimensional motion measurement and analysis system in the Biomechanics & Gait laboratory at the University of New South Wales. Forty reflective markers were placed on the subject to obtain the following joint angles: ankle, knee, hip, torso, shoulder, elbow, and wrist. The raw data were converted into the respective joint angles (Y, X, Z) for further analysis. The postural data was analysed using the University of Michigan???s Three-Dimensional Static Strength Prediction Program (3D SSPP) and the relative risk of injury was based on the following three values: (1) a threshold value of 3,400 N for compression force, (2) a threshold value of 500 N for shear force, and (3) population strength capability data. The effects on changes to the anthropometric data was estimated and analysed using the in-built anthropometric data contained within the 3D SSPP program for 6 separate lifter scenarios, these being male and female 5th, 50th and 95th percentiles. Changes to the patient load were estimated and analysed using the same computer software. Estimated compressive and shear forces were found to be lower with the drawsheet and tail component of the heads/tails lift in comparison to the use of the Blue MEDesign?? straps and head component of the heads/tails lift. The results obtained for the strength capability aspect of each of the lifts indicated a higher percentage of the population capable of both the drawsheet and tail end of the heads/tails lift. The relative risk of back injury for the lifters is distributed more evenly with the drawsheet lift as opposed to the heads/tails (tail) lift where risk is disproportionate with the heavier end being lifted. The use of lifter anthropometrics does not appear to be a realistic variable to base assumptions on which group of the population are capable of safely performing this task in a remote setting. This study advocates the use of the drawsheet lift in a remote setting based on the author???s experience and the biomechanical results obtained in this study. The drawsheet lift is both more accessible and provides a more acceptable risk when more than two patient handlers are involved, in comparison to the other lifts utilised lifting patients from floor to a chair.

No description available.