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A need to reduce the number of design iterations, coupled with a requirement to reduce the weight of the new generation of TPU running shoes has lead to the use of finite element analysis (FE) within the athletic shoe industry. The collaborators in this research, adidas, were already using the technology, but only on individual parts, and on a reverse engineered basis. This thesis presents a thorough review into the materials used in athletic footwear, their application within running shoes and the methods of testing non-linear, highly deformable polymers and polymer foams. The fundamentals of the FE process are examined, along with a discussion of the current testing methods for shoes. The novelty in this work comes mainly from the comprehensive, logical progression through the modelling process as applied to this new area. Sample materials were tested, revealing new test methods. These were then analysed and converted for use in ABAQUS v6.5 which was the FE software used. The modelling of the sample materials, their tests, then shoe parts and midsole assemblies are discussed at length. At each stage the required complexities were added to the model, and these are detailed. This includes the import, conversion and repair of highly complex geometry, meshing techniques for this geometry, methods of building models of shoe assemblies and all relevant issues that arose from these processes. In addition, a shoe with an internal mechanism was modelled to assist in the design process. The effect of damage to shoe materials was also studied. Physical tests were carried out to verify all the FE models, and the results are presented. In addition, shoes taken from the end of the production line with the uppers attached were tested in order to compare the change in performance between the component parts and a finished product. The results of the modelling showed that was possible to construct and run full shoe assembliesw ithin a reasonablet ime. Fair prediction of the physical responseo f the assemblies was seen using material data taken directly from the sample data, but a method of correcting the initial error in the material test is presented which gives very good force/deflection results in TPU parts. A method of adjusting the entire assembly's material models is then presented, which improves the initial verification. In addition to force/deflection readings, digital image processing was used to monitor the structural response of the shoe during loading, and a set of structural metrics is put forward. The results of these indicated that while the shoe models were representing the cushioning response well, the shape of the shoe was not replicated, suggesting that the model in its present state would be unsuitable for use in some forms of test. Suggestions for improvement are made. Comparison of the structural metrics between shoe assemblies and production shoes suggests the possibility of a quantifiable metric for what would be considered a 'good' shoe. The repercussions of this are discussed in the conclusions.

There is evidence to suggest that the bending stiffness of footwear can be adapted to influence sprinting performance. In addition, it has been suggested that to achieve maximal performance, the mechanical properties of this footwear needs customising to an individual athlete. Due to a lack of detailed biomechanical data, the influence of longitudinal bending stiffness on the dynamics of the lower extremity during sprint running remains largely unexplained and is subject to considerable speculation. Thus, the aim of this work is to develop functional sprint footwear in a range of different longitudinal bending stiffnesses in order to explore the effects on measures of sprinting performance and lower extremity dynamics. Novel mechanical test procedures were developed and benchmark properties of current commercial sprint spikes were ascertained. Bending stiffness data showed considerable variability amongst those sprint spikes aimed at athletes of a higher competitive standard, which indicates that there is no consensus regarding optimum stiffness. A kinematic analysis of barefoot and shod sprinting was undertaken to investigate the influence of sprint footwear on lower extremity kinematics. Medial and lateral sagittal plane data were collected at the start and in the acceleration (10 m) and maximal speed (50 m) phases of a 100 m distance. Metatarsophalangeal joint (MPJ) angular range and velocity were significantly reduced in sprint spikes compared to barefoot conditions and the magnitude of the controlling affect was larger at 10 m compared to 50 m. Selective laser sintering of nylon was used to produce a number of sprint shoe sole units each of different thickness. These were attached to standard uppers to produce a range of longitudinal bending stiffnesses encompassing those already commercially available. The influence of shoe stiffness on sprinting perfonnance was assessed using specific jump metrics that were selected for use based on their high correlations with sprinting perfonnance during starting and maximal speed sprinting. Results indicated that sprint shoe longitudinal bending stiffness influenced the dynamics of the lower extremity during squat and bounce drop jumps. The relationship between maximal perfonnance and shoe stiffness was specific to the jump metric; best performance was achieved in intermediate stiffness shoes for the squat jumps and high stiffness for bounce drop jumps. Six bespoke pairs of sprint shoes with bending stiffness spanning and exceeding that of current commercial sprint spikes were developed. Results showed that MPJ and ankle joint dynamics were affected by longitudinal bending stiffness during squat and bounce drop jumps. Angular velocities of the MP and ankle joints were significantly reduced with increasing longitudinal bending stiffness. For the squat jump, ankle joint moments increased with shoe longitudinal bending stiffness and reached an individually optimal level within the stiffness range. This was also the case for ankle joint power and mechanical energy. The bounce drop jump saw mechanical energy generation at the MPJ increase with shoe longitudinal bending stiffness. Different levels of longitudinal bending stiffness were required for maximal performance in each jump type. This infers that sprint shoe bending stiffness requirements may vary according to the phase of the race. Furthermore, individual responses to different stiffnesses highlighted the importance of personalising mechanical properties to the requirements of a particular athlete for maximal performance. This research has focused on the use of discrete jump metrics to assess performance and therefore future work should aim to investigate the implications of different stiffness conditions using measures of actual sprinting. Also, further detailed musculoskeletal explorations are required in order to fully understand the precise mechanism by which longitudinal bending stiffness influences performance.

Musculoskeletal disorders (MSDs) frequently affect the health and well-being of workers and can hinder growth in the industrial sector. Research indicates that user requirements to reduce workplace risk factors for MSDs are not always effectively conveyed to practitioners of design. This creates a mismatch between these requirements and what is ultimately produced. Quality function deployment (QFD) is a structured collaborative design approach, widely used in industry. The aim of this research was to explore the potential of a QFD-based design tool to enhance such communication in the design process and help reduce work-related MSDs. In order to evaluate user knowledge and ability to identify workplace risks and the subsequent requirements for design, a multi-methods study was undertaken with cleaners (n= 10), joiners (n= 6) and plumbers (n= 6) and their line managers (n= 6). Methods included semi-structured interviews, task analysis, REBA and body part discomfort maps. The findings revealed that these workers were in general able to identify risks to their musculoskeletal health and make design suggestions related to specific tasks. All of the workers expressed concern about manual handling, and issues related to awkward postures were also identified by the majority. A QFD-based design tool (with guidance material) was then developed to facilitate communication in the design process. It consisted of six features to encompass the design process, and included tools and techniques with supplementary templates to aid practitioners. In order to evaluate its feasibility with respect to current practice, an online questionnaire survey was conducted with a cohort of practitioners of ergonomics and design (n= 32). Of these, the majority rated highly the importance of an integrated approach for participatory design to help reduce work-related MSDs. They also suggested elements to be included in the design tool, which were in congruence with the features already included. To evaluate the strengths and weaknesses of the design tool in the field setting, in-depth interviews using a walkthrough approach (n= 8) and case studies of specific work tasks (n= 3) were conducted with practitioners. The findings showed that the design tool would be very useful in managing and presenting design information. In particular, practitioners liked being provided with design principles to help systematically identify design solutions to reduce risks and using the QFD-based matrices to present such information. Limitations of the tool were identified as inadequacy of guidance, the lack of automated procedures and the time required to set up and learn. The design tool (and guidance material) seems to have potential in facilitating the sharing of design information among the stakeholders of the design process.

The terms "abusive head injury" and "shaken baby syndrome" refer to a unique pattern of non-accidental traumatic injury occurring in children that many clinicians and researchers have good reason to believe is caused by violent shaking. Typical injuries include subdural haemorrhage, retinal haemorrhage as well as tears to cortical bridging veins. A major paradox is that the injuries induced by a shaking event are much more severe than those caused by even violent single - impact head trauma, despite the relatively low accelerations in shaking. Infants younger than 6 months are significantly more vulnerable to the shaken baby syndrome than older infants and children, and one possible explanation is given that the softness of the infant brain and compliant skull structure allows violent motions to be set up (Cheng et al. 2005). These new mechanisms, could have an important role in explaining the basic mechanics of shaken baby syndrome. Several models of infant head have been created with the optimized anatomical detail and accurate constitutive material properties from literature. The driving input to these models is derived from data generated in our research programme at the Transport Research Laboratory (TRL) (Brudenell 2000) with the theory of kinematics rigid body reconstruction. Numerical simulations are applied by using the finite element system LS-DYNA, and the consequences have been correlated with clinically observed damage in infant victims, and the brain skull boundary condition is investigated via the fluid structure interaction (FSI) method. A shaking testing apparatus has been custom designed with computer aided design methodology (CAD), and is manufactured and assembled in the workshop. The driving of the rig is able to apply stable, repetitive linear motion within the range of accuracy and magnitude of human shaking. An experimental model has been constructed and mounted on the rig with important structures consisting of brain, cerebrospinal fluid (CSF), skull and infantile membrane. The system validates the computational modelling by demonstrating the relative motion of the continuum system within the transparent skull replica. The research, as a first exploration in this area, contributes to the study of the infant abusive head injury, and is able to draw the data together in a discussion of the implications for the mechanics of the shaken baby syndrome.

The term 'Microshock' refers to a phenomenon in which transient electrical discharges occur through a small air gap between two electrodes at different potentials. Induced voltages on the human body can cause the discharges to people. It is the sensation caused by these discharges which is known as a 'microshock'. In a typical microshock, the current passing through the human body is tens of amps but its duration is few hundred nanoseconds. Microshocks are considered annoying and unpleasant even though their energy is well below the harmful threshold. Since information relating to microshock activity is limited, the main objective of this research is to better understand microshock activity and the perception of it by human beings. In particular it was intended to examine whether various physical scales of experimentation accurately represent the physical phenomena experienced by real people. The overall research consists of four parts: Firstly, an experimental setup was built in a small cage to investigate the characteristics of microshocks and to measure breakdown voltages with different electrode geometries, gap lengths, surface conditions and materials. Experimental outcomes show a 45% reduction of breakdown voltage with point-plane (r=0.20 mm) compared to sphere-plane (r=9.51 mm) electrodes. However this reduction is not proportional to the maximum electric field enhancement of 4.6 times the average. Significant reduction of breakdown voltage is seen when using meat electrodes. Moving electrodes show multiple discharges on closing and opening a gap, consistent with previous published work. The environmental conditions were also examined but showed no significant impact on breakdown voltage. Secondly, microshock discharge activities were examined in a controlled HV laboratory environment. Human perception to microshocks was investigated by carrying out a series of experiments first with a life-size model, and then with a real person. The relationships between the microshock voltage magnitude, the frequency of microshock occurrence, the conductor voltage, and the size of the air gap were analysed and suggest the importance of the number of half cycles of discharge on people's perception rather than the total number of discharges. Thirdly, experimental work was extended to an outdoor field environment, first with a model man and then with real people to understand the perception levels and microshock characteristics on people. Finally, a model was constructed using the PSCAD/EMTDC software package to study the characteristics of the microshock voltage waveforms and to model the experimental work with circuit theory. The four parts of the project are shown to give entirely consistent results. It is also shown that only when voltages above 1000 V are induced on people do they experience annoyance at microshocks. Above 2000 V microshocks become painful. Laboratory tests are shown to represent service conditions, and simple circuits may be used to model the discharge processes. Biological electrodes have been shown to create slightly different discharge characteristics which may account for variations in personal sensitivity to microshocks. This requires further investigation.

Aims: To characterise the distribution of peak bone mass at the total hip, lumbar spine (LS) and total body (TB) sites of women from one European Caucasian (EC) and two South Asian populations, namely Pakistani Muslims (PM) and Gujarati Hindus (GH), residing in the UK, and to explore whether variations of lifestyle and other non-genetic putative risk factor characteristics may explain any variation in peak bone mass between the EC and South Asian groups. Methods: Women, aged 18 years to 36 years, were recruited from primary care age-sex registers from practices located within Greater Manchester. Women were mailed a screening questionnaire concerning various lifestyle factors. Those women who replied, were invited to attend for a more detailed interview-assisted lifestyle questionnaire, assessments of height, weight and waist-to-hip ratio, bone density (BMD) at the total hip, LS and TB, fat mass (FM) and lean mass (LM) and blood tests for serum calcium, parathyroid hormone (PTH) and 25 hydroxyvitamin D (25 OHD). Results: The participation rates for BMD screening, were 19%, 9% and 14% for EC, PM and GH women respectively. EC and GH women who completed the screening questionnaire were slightly older than those who did not. Based on a study comparing responses to the screening questionnaire, differences in characteristics between those who attended for BMD screening and those who did not, for all three ethnic groups , were generally small and the direction inconsistent in terms of benefit or detriment to BMD. BMD data was available on 118 EC, 98 PM and 28 GH women. Compared to PM, EC had significantly higher BMD at the hip (0.962 g/cm2 vs 0.916 g/cm2 ), LS (1.031 g/cm2 vs 0.984 g/cm2) and TB (1.096 g/cm2 vs 1.058 g/cm2). Although BMD at all three sites were higher among EC compared with GH, differences were small and non-significant. There were no significant differences in LS BMAD (calculated by dividing areal BMD by subject height), between EC and either South Asian group. When comparing EC and PM women, adjusting for age and separately for height, LM, maximum non-pregnant weight, serum 25 OHD, PTH, dietary calcium consumption or vitamin D consumption, eliminated significant BMD differences at all three sites, adjusting for weight eliminated differences at the hip and LS, while adjusting for hormonal contraception use eliminated differences at the hip only. In multivariate models, at the hip, after adjusting for age, weight, height, 25 OHD, PTH, dietary calcium consumption and hormonal contraception use, at the LS, after adjusting for these characteristics (other than hormonal contraception use) and at the TB, after adjusting for age, height, LM, 25 OHD, PTH and dietary calcium consumption, BMD was significantly higher in PM women (b coefficient for PM with EC as referent = 0.063, 0.064 at the hip, LS and TB respectively).

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The potential of carbon nanofilaments for use in surface modification of implants and as fillers in biocompatible polymer composites was investigated with particular respect to nanofilament size and structure. Carbon nanofilaments were synthesised using chemical vapour deposition or obtained commercially, which provided a range of carbon nanofilament average diameters (13 nm, 134 nm, 142 nm, 155 nm) and structures (platelet, platelet and herringbone, multi-walled nanotubes and vapour-grown nanofibres). The topography and texture of pressed nanofilament substrates was dependent on the nature of the nanofilaments, producing lower micron-scale roughness (Ra) values in the GNF samples (0.5-2.0 µm) compared to the MWNT9 and PR19PS substrates (3-4 µm), but no significant differences in nanoscale roughness (Ra~150 nm). Human osteoblast response to these substrates was measured. Cells attached and spread to substrates with average nanofilament diameters of 134-155 nm (GNF1, GNF3 and PR19PS) rather than 13 nm (MWNT9) after 90 minutes, but proliferated and differentiated greater on the rougher nanotube samples over 14 days (MWNT9 and PR19PS). Investigation of polymer/carbon nanofilament composites revealed the following. Low concentrations of nanofilament addition into poly(ethyl methacrylate)/tetra furfuryl methacrylate reduced the surface roughness of the polymer (Ra: 1.7 µm) by up to 88 % (5 wt% GNF composite), and reduced the storage modulus by 26-68 % of the unfilled polymer (1591 MPa at 37 °C). The electrical resistivity of the composites was significantly reduced due to addition of nanofilaments; all samples reaching percolation just above 10 wt% but with different resistivities (~30 Ω.m at 15 wt% PR19PS, ~10 Ω.m at 15 wt% GNF and ~0.15 Ω.m at 15 wt% MWNT9). Human osteoblast attachment on the PEMA/THFMA composites followed trends in roughness, attaching in higher quantities but with less spreading to rougher surfaces (i.e. higher nanofilament concentrations) on all samples except on the 5 wt% MWNT9 composite, which showed high spreading and attachment. This sample also showed the greatest degree of proliferation and differentiation over 14 days of culture. Faradic stimulation of human osteoblasts was investigated by pulsing 10 µA of electrical current through 5 wt% MWNT9 composite samples for 6 hours daily over 14 days. There was a slight increase in osteoblast proliferation when stimulating the 5 wt% MWNT9 composite sample with pulsed current compared to unstimulated 5 wt% MWNT9 composite controls. The investigation indicated that the size and nature of carbon nanofilaments affected the surface and bulk properties of pressed nanofilament substrates and nanofilament -PEMA/THFMA composites. Human osteoblasts responded to the size of nanofilaments, especially their diameter, but also with respect to their effect on surface roughness. This was thought to be related to their dimensional similarity to extracellular matrix components in bone tissue. Carbon nanofilaments could therefore potentially be used to texture surfaces and improve bulk properties in biomaterials, particularly in total joint components, bone cements, or tissue engineered scaffolds that could also be electrically stimulated to promote osseointegration. This work also instigates further investigation into the toxicity and reinforcing capabilities of carbon nanofilaments.