Support-Free Infiltration of Selective Laser Sintered (SLS) Silicon Carbide Preforms

Non-metallic objects are often difficult to manufacture due to high melting temperatures, poor sinterability, limited ductility, and difficulty in machining. Freeform fabrication techniques coupled with liquid infiltration offer a cost-effective and rapid manufacturing mechanism for composite parts with complex geometry and adequate properties. Selective laser sintered (SLS) silicon carbide (SiC) preforms infiltrated with liquid silicon develop localized infiltrant overextrusions onto surfaces and at surface irregularities. Several shrinkage mechanisms including densification were studied as possible causes of these overfilling extrusions, and the results are discussed below. This research was supported by NSF Grant Number DMI-0522176.Mechanical Engineerin

Associations between retirement reasons, chronic pain, athletic identity, and depressive symptoms among former professional footballers

Background: Retirement from professional sport has been recognised as a major psychological stressor, and there is a need to identify factors that increase the risk of mental health problems after career termination. The current study examined associations between career-ending injury, chronic pain, athletic identity and depressive symptomology in retired professional footballers. Methods: A cross-sectional study was performed with 307 retired male footballers who had played within a professional United Kingdom league. Participants completed measures of depressive symptoms (Short Depression-Happiness Scale), chronic pain (Pain Intensity Numerical Rating Scale), and athletic identity (Athletic Identity Measurement Scale), and reported their reasons for retirement. Results: A total of 48 participants (16%) met the cut-off score for possible cases of clinically-relevant depression. These participants were more recently retired, and had higher athletic identity than those without depressive symptoms. Former players with depressive symptoms were more likely to cite injury as a retirement reason, and report higher levels of ongoing injury-related pain. Multivariate logistic regression revealed that presence of depressive symptoms was independently associated with retirement through injury (OR = 3.44; 95% CI = 1.39, 8.51), higher pain levels (OR = 1.38; 95% CI = 1.02, 1.86), and increased athletic identity (OR = 1.28; 95% CI = 1.14, 1.44). Conclusions: Career-ending injury is strongly associated with higher odds of depressive symptomology during retirement, while experiencing chronic pain, and maintaining a high sense of athletic identity, are additional potential contributors

Affective outcomes during and after high-intensity exercise in outdoor green and indoor gym settings

© 2017 Informa UK Limited, trading as Taylor & Francis GroupOutdoor exercise settings promote greater psychological well-being than synthetic equivalents, although the influence of the exercise context has not been investigated at high exercise intensities. This study compared the psychological effects of high-intensity exercise in outdoor green and indoor gym settings in 22 adult runners using a randomized repeated measures design. Affect and perceived exertion were assessed before, during, and after a 6000-m run with the second half completed at maximum effort. Perceived exertion and activation increased in a progressive manner from baseline to 6000 m, and decreased during the 10-min recovery post-run. Non-significant reductions in affective valence were observed between 3000 and 6000 m, followed by a significant increase post-run. Outcomes did not differ at any time point between the settings. This study suggested that regular runners experience positive affective responses during and after high-intensity exercise in both a natural outdoor environment and an indoor gym

Facilitating participation in health-enhancing physical activity: a qualitative study of parkrun

Background Public health guidelines emphasise the value of vigorous intensity physical activity, but participation levels are low. Purpose This study was aimed at identifying factors contributing to initial and sustained engagement in parkrun in the UK, to inform the design of community-based interventions promoting health-enhancing physical activity. Methods Semi-structured interviews were conducted by telephone with 48 adult participants of parkrun, a national network of weekly, free, volunteer-led, timed 5 km runs in public spaces. The framework approach was used for thematic analysis of transcripts. Results Two overarching themes emerged: freedom and reciprocity. Freedom referred to the accessibility and inclusivity of events, both of which contributed to initial attendance and sustained involvement. Reciprocity related to the dual opportunity for personal gain and for helping others. Anticipation of fitness and health benefits were important for initial motivation. However, additional aspects motivating continued involvement included achievement of time or attendance goals, social cohesion, and contributing to the community. Conclusions Specific features of the parkrun experience encouraged participation including the accessible, inclusive ethos, achievement opportunities, and inherent social support, along with the outdoor natural settings, and integrated volunteer system. The inclusion of these elements in community-based interventions may increase success in initiating and maintaining health-enhancing physical activity

Exploring parkrun as a social context for collective health practices: running with and against the moral imperatives of health responsibilisation.

Critiques of public health policies to reduce physical inactivity have led to calls for practice-led research and the need to reduce the individualising effects of health promotion discourse. This paper examines how parkrun – an increasingly popular, regular, community-based 5km running event – comes to be understood as a ‘health practice’ that allows individuals to enact contemporary desires for better health in a collective social context. Taking a reflexive analytical approach, we use interview data from a geographically diverse sample of previously inactive parkrun participants (N=19) to explore two themes. First, we argue that parkrun offers a space for ‘collective bodywork’ whereby participants simultaneously enact personal body projects while also experience a sense of being “all in this together” which works to ameliorate certain individualising effects of health responsibilisation. Second, we examine how parkrun figures as a health practice that makes available the subject position of the ‘parkrunner’. In doing so, parkrun enables newly active participants to negotiate discourses of embodied risk to reconcile the otherwise paradoxical experience of being an ‘unfit-runner’. Findings contribute to sociological understandings of health and illness through new insights into the relation between health practices and emerging physical cultures, such as parkrun

Exploring the role of social capital in community-based physical activity: qualitative insights from parkrun

© 2017 Informa UK Limited, trading as Taylor & Francis Group There is a need to address social inequalities related to health and physical activity. Taking a practice-led approach to intervention research, this paper uses the case of parkrun – a rapidly growing weekly running initiative – to explore the potential of free, community-based opportunities to improve physical activity in low socio-economic groups. Our approach departs from individualistic behavioural research and draws on the concept of social capital in order to add to the sociological understanding of physical (in)activity. Interviews were carried out with previously inactive parkrun participants and were analysed thematically through the lens of social capital. Our analysis illustrates how: (1) participants often draw on existing social ties (family, friends, neighbours and colleagues) to initiate their participation in parkrun, (2) participants invest in and benefit from the aggregate labour of the wider parkrun community (their network of social relations) and therefore are privy to significant practical and affective support and (3) participants utilise acquired social capital to accumulate cultural capital related to injury management, performance and health. These findings add qualitative insight into existing literature highlighting social capital as a key resource in the initiation and maintenance of physical activity. In the ongoing effort to provide viable physical activity opportunities for low socio-economic groups, we optimistically argue that volunteer-led, community-based initiatives have the capacity to mobilise resource through social networks. However, in the context of persistent socio-economic inequalities, it is likely that relying on existing social capital to promote health-enhancing behaviour will limit the impact of this approach

Changes in physical activity, weight and wellbeing outcomes among attendees of a weekly mass participation event: a prospective 12-month study.

Background: Mass participation events are recognized as a way of engaging low-active individuals in health-enhancing physical activity, but there is a need to investigate the sustained effects on behaviour and health. This study aimed to examine changes in self-reported physical activity, weight and wellbeing over 12 months in participants of parkrun, a weekly mass participation 5 km running event. Methods: New parkrun registrants (n = 354) completed self-reported measures of physical activity, weight, happiness and stress, at registration, 6 months and 12 months. Objective data on attendance and fitness (i.e. run dates and finishing times) were obtained from the parkrun database. Results: Overall physical activity levels were high at baseline, but significantly increased over the first 6 months, before declining. By 12 months, weekly physical activity was 39 min higher than baseline. Significant reductions in body mass index were observed over 12 months, with a weight loss of 1.1% in the whole sample, and 2.4% among overweight participants. Modest increases in happiness and decreases in perceived stress were recorded. Run times suggested a 12% improvement in fitness during the study. Conclusion: Significant changes in weight, fitness and wellbeing outcomes indicate the public health benefits of regular participation in parkrun

Prospective associations between leisure-time physical activity and cognitive performance among older adults across an 11-year period

Background: Few studies have explored the relations between naturally occurring changes in physical activity and cognitive performance in later life. This study examined prospective associations between changes in physical activity and cognitive performance in a population-based sample of Taiwanese older adults during an 11-year period. Methods: Analyses were based on nationally representative data from the Taiwan Health and Living Status of the Elderly Survey collected in 1996, 1999, 2003, and 2007. Data from a fixed cohort of 1160 participants who were aged 67 years or older in 1996 and followed for 11 years were included. Cognitive performance (outcome) was assessed using 5 questions from the Short Portable Mental Status Questionnaire. Physical activity (exposure) was self-reported as number of sessions per week. The latent growth model was used to examine associations between changes in physical activity and cognitive performance after controlling for sociodemographic variables, lifestyle behaviors, and health status. Results: With multivariate adjustment, higher initial levels of physical activity were significantly associated with better initial cognitive performance (standardized coefficient β = 0.17). A higher level of physical activity at baseline (1996) was significantly related to slower decline in cognitive performance, as compared with a lower level of activity (β = 0.22). The association between changes in physical activity and changes in cognitive performance was stronger (β = 0.36) than the previous 2 associations. The effect remained after excluding participants with cognitive decline before baseline. Conclusions: Physical activity in later life is associated with slower age-related cognitive decline

Identification of research priorities in exercise oncology: a consensus study

The growth of research in the field of exercise oncology has resulted in a large evidence base for the role of physical activity in preventing and managing cancer outcomes. Nonetheless, there remain many unanswered questions across the multidisciplinary field. This study aimed to determine the priority research questions within exercise oncology using a systematic consensus method. Forty-seven exercise oncology experts engaged in the five-step process of the Nominal Group Technique to generate a list of research questions in small groups and rank the 10 most important. One hundred questions resulted from the process and fifteen received total scores (sum of ranks) of at least 50 from a maximum score of 470. The highest ranked question (score of 125) related to the identification of functional markers of recovery. The next five questions concerned minimum exercise parameters, health professional education, translation of behavioural interventions, effects of exercise on the tumour microenvironment and development of in vitro models to study the impact of exercise on cancer cell growth and metastasis. The study has demonstrated the importance of future research across all disciplinary areas of exercise oncology and identified the priority questions to which resources might be directed