'My parkrun friends.' A qualitative study of social experiences of men at parkrun in Ireland.

Social support is a well-established determinant of mental wellbeing. Community initiatives, which combine a purposeful activity with social connection, may be appropriate to promote the mental wellbeing of middle-aged men in Ireland-a group at risk of poor mental wellbeing due to social isolation. parkrun offers free, weekly, 5km run or walk events in 22 countries. This study aims to explore the social experience of parkrun participation for middle-aged men in Ireland and considers how social connections made at parkrun relate to mental wellbeing. Online semi-structured interviews were conducted in 2022/23 with 39 men aged 45-64 years, who run, walk or volunteer at parkrun in Ireland, recruited purposively in rural and urban communities. Men with a range of parkrun experience gave interviews lasting a mean of 32 minutes. Interviews were recorded and transcribed verbatim. Reflexive thematic analysis resulted in three themes and ten subthemes. The men described parkrun as offering a welcoming and supportive environment (Theme 1). Men at parkrun could choose the level of social connections, building strong or weak social ties to provide social support and improve mental wellbeing (Theme 2). Social engagement with parkrun evolved following repeated participation (Theme 3). The results suggest that parkrun is a suitable community initiative for middle-aged men at risk of poor mental wellbeing due to social isolation. Social connections were developed after repeated participation in parkrun and these connections improved subjective mental wellbeing. The findings from this study could be used to design new initiatives for mental health promotion.

How can UK public health initiatives support each other to improve the maintenance of physical activity? Evidence from a cross-sectional survey of runners who move from Couch-to-5k to parkrun.

Physical activity improves physical and mental well-being and reduces mortality risk. However, only a quarter of adults globally meet recommended physical activity levels for health. Two common initiatives in the UK are Couch-to-5k (an app-assisted 9-week walk/run programme) and parkrun (a free, weekly, timed 5-km walk/run). It is not known how these initiatives are linked, how Couch-to-5k parkrunners compare to parkrunners, and the extent to which this influences their parkrun performance. The aims were to compare the characteristics and motives and to compare physical activity levels, parkrun performance and the impact of parkrun between Couch-to-5k parkrunners and parkrunners. Three thousand two hundred and ninety six Couch-to-5k parkrunners were compared to 55,923 parkrunners to explore age, sex, ethnicity, employment status, neighbourhood deprivation, motives, physical activity levels, parkrun performance and the impact of parkrun. Couch-to-5k parkrunners were slightly older, more likely to be female and work part-time, but similar in ethnicity, and neighbourhood deprivation compared with other parkrunners. Couch-to-5k parkrunners had different motives for participation and reported high levels of physical activity at registration, which remained to the point of survey completion. This group had slower parkrun times but, when registered for a year, completed a similar number of runs (11) per year. Larger proportions of Couch-to-5k parkrunners perceived positive impacts compared with other parkrunners and 65% of Couch-to-5k parkrunners reported improvements to their lifestyle. parkrun appears to be an effective pathway for those on the Couch-to-5k programme, and the promising positive association between the two initiatives may be effective in assisting previously inactive participants to take part in weekly physical activity.

Parkrun as self-managed cardiac rehabilitation: secondary analysis of a cross-sectional survey of parkrun in the UK.

OBJECTIVES: Cardiac rehabilitation following a cardiovascular disease (CVD)-related illness has been shown to reduce the risk of heart attack and hospital admission. The American College of Sports Medicine recommends 3-5 days per week of moderate to vigorous exercise. Despite this, only 38% of those eligible complete rehabilitation programmes. Parkrun organises free, weekly, timed, 5 km running or walking events. The aim of this study was to investigate whether parkrun can support self-managed cardiac rehabilitation. METHODS: We undertook a secondary analysis of a survey of UK parkrunners, comparing responses of those reporting no health conditions (n=53 967) with those with one or more CVD-related conditions (n=404). Thematic analysis was used to analyse 53 open-ended text comments from the latter. RESULTS: Four hundred and four respondents (0.7% of the total) reported CVD-related conditions with the largest proportions among those walking the event (24% of male participants and 5% of female participants). For those doing <3 days per week of physical activity at registration, 47% increased activity to ≥3 days per week. Among those with CVD-related conditions, participation in parkrun led to perceived improvements in fitness (81% of participants), physical health (80% or participants) and happiness (74% of participants). Two thirds reported improvements to their ability to manage their condition(s) and half to their lifestyle choices. Analysis of 53 open-text comments revealed that those with CVD-related conditions used parkrun to monitor their condition and were motivated by encouragement from the parkrun community. Enjoyment and fun were important for engagement, although some individuals were dispirited by poor performance due to their conditions. CONCLUSIONS: Individuals with CVD-related conditions used parkrun to self-manage their rehabilitation; this applied to those attending parkrun following disease onset as well as those engaged with parkrun prior to their condition. Parkrun, or events with similar characteristics, could support self-managed cardiac rehabilitation.

parkrun participation, impact and perceived social inclusion among runners/walkers and volunteers with mental health conditions.

Engagement in recreation can positively impact the physical and mental health of those experiencing mental health challenges; however, the impact of engaging in other aspects of such recreation, such as volunteering, remain largely unexplored in this population. Volunteering is known to have a wealth of health and wellbeing benefits among the general population; therefore, the impact of recreational-based volunteering for those with mental health conditions deserves to be explored. The current study sought to examine the health, social and wellbeing impacts of parkrun engagement among runners and volunteers living with a mental health condition. Participants with a mental health condition (N = 1661, M(SD)age = 43.4 (12.8) years, 66% female) completed self-reported questionnaires. A MANOVA was conducted to examine the differences in health and wellbeing impacts between those who run/walk vs. those who run/walk and volunteer, while chi-square analyses examined variables of perceived social inclusion. Findings suggest that there was a statistically significant multivariate effect of participation type on perceived parkrun impact (F (10, 1470) = 7.13; p < 0.001; Wilk's Λ = 0.954, partial η2 = 0.046). It was also found that for those who run/walk and volunteer, compared to those who only run/walk, parkrun made them more feel part of a community (56% v 29% respectively, X2(1) = 116.70, p < 0.001) and facilitated them meeting new people (60% v 24% respectively, X2 (1) = 206.67, p < 0.001). These results suggest that the health, wellbeing, and social inclusion benefits of parkrun participation are different for those who run and volunteer, compared to those who only run. These findings may have public health implications and clinical implications for mental health treatment, as they convey that it is not simply the physical engagement in recreation that may play a role in one's recovery, but also the volunteer aspect.

Change in health, wellbeing and physical activity levels during the COVID-19 pandemic: a longitudinal cohort of parkrun participants in the United Kingdom.

Lockdown restrictions imposed across the UK in response to the coronavirus disease 2019 (COVID-19) pandemic had a profound impact on many people's health and wellbeing. People were encouraged to be active, but population surveys suggest some groups found this easier than others. We explored the changes in health, wellbeing and physical activity levels among a sample in the UK who experienced the sudden loss of a weekly community-based physical activity opportunity, parkrun. A sample of UK parkrun participants responded to two surveys: pre-COVID-19 in January/February 2019 and during the COVID-19 pandemic in September 2020. Outcomes were happiness, life satisfaction, connections with others, physical health, mental health and physical activity. The sample was stratified by gender, age, deprivation status, physical activity and number of parkruns completed. Demographics were reported using descriptive statistics; distributions between sub-groups were compared using Chi-square tests while differences in outcomes were determined using the Mann-Whitney U test. Open text responses were also analysed. Happiness, life satisfaction, connections with others, physical health and mental health of 450 parkrun participants were negatively impacted for all sub-groups, although the impact was not experienced equally. Physical activity fell by 6% while happiness and life satisfaction fell by 12%. People experienced the worst negative impact on their connections with others. The COVID-19 pandemic negatively impacted the wellbeing of a greater proportion of females, younger adults, inactive people, those from higher deprivation areas, and those who had completed fewer parkruns. There is evidence that the wellbeing of those who were more active, and those more involved in a community-based physical activity initiative pre-pandemic, was less negatively affected during the COVID-19 lockdown.

parkrun and the promotion of physical activity: insights for primary care clinicians from an online survey.

BACKGROUND: To support efforts to increase social prescribing and reduce levels of physical inactivity, parkrun UK and the Royal College of General Practitioners together developed the parkrun practice initiative to link general practices to local parkruns (free, weekly, timed, physical activity events). General practice staff are encouraged to take part in parkrun events themselves and to encourage patients to participate. AIM: To provide insights for primary care clinicians about parkrun participants (parkrunners), especially those with characteristics of patients who might be signposted to physical activity. DESIGN AND SETTING: Secondary analysis of an online survey of parkrunners in the UK. METHOD: Responders were ranked into 13 categories using mean parkrun finish time, allowing the following definitions: front runners; median runners; slower runners; runners/walkers; and walkers. Measures included demographics, health conditions, motives for first participating, and perceived impact on health and wellbeing. RESULTS: The survey included 45 662 parkrunners. More than 9% of all participants and 45% of walkers were found to have at least one long-term health condition, including arthritis, obesity, depression, hypertension, chronic pain, anxiety, type 2 diabetes, and asthma. Walkers were less likely to be motivated by fitness or competition, and were more likely to be motivated by physical health. Despite these differences, perceived improvements to wellbeing were broadly similar for all parkrunners, regardless of their finishing time. CONCLUSION: Parkrunners are a diverse population in terms of their physical health. Information provided by this study could be combined with other research on the barriers to participation and successful brief interventions to help address the key issues of primary care clinicians' knowledge and confidence about social prescribing to increase patients' physical activity levels.

The influence of neighbourhood equity on parkrunners in a British city.

Physical activity benefits both physical and mental health. Specific events may augment participation in physical activity at a population level. Parkrun is a popular, free, weekly, timed 5 km run or walk in public spaces located in five continents. However, these events may be distributed inequitably, possibly reinforcing inequities in health. As a prelude to a comprehensive analysis of a larger dataset, we explore a hypothesis that participation in parkrun is influenced by the socio-economic characteristics of both parkrunners and their park. Two parkruns, 4.5 km apart, were selected in the city of Sheffield in the United Kingdom. Defined by indices of multiple deprivation, Castle parkrun is located in an economically deprived neighbourhood and Hallam parkrun is in a prosperous area of the city. Parkrunners were defined by applying these same indices to the neighbourhood of home registration. Results: (i) the prosperous Hallam catchment area produced over five times more parkrun participants than Castle; (ii) compared with Castle, Hallam parkrun attracted more participants from both catchment areas; (iii) consequently, Hallam parkrun had seven times more participants than Castle parkrun. Conclusion: establishing parkruns in deprived areas is a necessary but not sufficient prerequisite for equity of participation in this heath promoting activity.

Parkruns are popular, free, weekly, timed 5 km runs or walks in public places across the world. They contribute to both mental and physical health. But they could also increase health inequality. Participants may already have the better health generally associated with above average incomes and home life in attractive neighbourhoods. Our pilot study compares two parkruns in the British city of Sheffield; one located in the city's poorer East End, the other in the richer West End.

The health benefits of volunteering at a free, weekly, 5 km event in the UK: A cross-sectional study of volunteers at parkrun.

This paper investigates the motives for first participating in parkrun and its impact for those who volunteered compared to those who did not volunteer. A cross-sectional survey was emailed to parkrun registrants, resulting in 60,680 survey returns from parkrun participants who self-identified as volunteers only (n = 681), runners/walkers who volunteered (n = 21,928) or runners/walkers who did not volunteer (38,071). Two survey questions were analysed in this paper: (1) their motives for first participating in parkrun as a volunteer or runner/walker; and (2) the perceived impact on their health and wellbeing. More than half of respondents were female and were predominantly from a white ethnic background. Compared to runners/walkers who volunteered, those who volunteered exclusively were older, more likely to be retired and more likely to be inactive at registration. Exclusive volunteers were motivated by wanting to give something back to the community (45.8%), to feel part of a community (26.1%), to help people (24.5%) or because they were unable to run (21.1%). Runners/walkers who volunteered were more likely to volunteer because they felt obliged to (49.3%). A large proportion of exclusive volunteers reported improvements to connections with others such as feeling part of a community (83.5%), the number of new people met (85.2%) and time spent with friends (45.2%). While mental and physical health were ranked low by volunteers as a motive (4.7% and 2.7% respectively), improvements were reported by 54.5 and 29.3% respectively. The data shows that volunteering at parkrun without participating as a runner or walker can deliver some of the components of the Five Ways to Wellbeing advocated by the NHS. The characteristics of parkrun (free, regular, local, accessible and optional) make it a viable social prescribing offer that can be used as a model for other community events seeking to attract volunteers.

Motivation to Improve Mental Wellbeing via Community Physical Activity Initiatives and the Associated Impacts-A Cross-Sectional Survey of UK parkrun Participants.

Participation in regular physical activity is a well-established strategy to support good mental wellbeing in adults with, and without, mental health conditions. The physical activity initiative parkrun is a free, weekly, timed, running and walking event which is attended by people from the local community of all abilities. The purpose of this study was to investigate the mental wellbeing of UK parkrun participants along with their motives for taking part and the impact of participation. Mental health conditions were self-reported in 2.5% of 60,000 respondents to an online survey of parkrunners, with the most prevalent being depression and anxiety. Those with mental health conditions were more motivated than those without to first participate in parkrun to manage their health conditions and improve their mental health. Those with mental health conditions were equally motivated to improve their physical health when compared to those without, and reported similar levels of improvement. Mental wellbeing scores for those with mental health conditions were close to the normal range, suggesting that engagement in parkrun may have had a role in limiting the effect of their illness. Community initiatives could replicate parkrun's model, and use the potential for both mental and physical health improvement, as well as health condition management, as a motivation for participation.

Exploring the benefits of participation in community-based running and walking events: a cross-sectional survey of parkrun participants.

BACKGROUND: Whilst the benefits of physical activity for health and wellbeing are recognised, population levels of activity remain low. Significant inequalities exist, with socioeconomically disadvantaged populations being less physically active and less likely to participate in community events. We investigated the perceived benefits from participation in a weekly running/walking event called parkrun by those living in the most socioeconomically deprived areas and doing the least physical activity. METHODS: A cross-sectional online survey was emailed to 2,318,135 parkrun participants in the UK. Demographic and self-reported data was collected on life satisfaction, happiness, health status, physical activity, motives, and the perceived benefits of parkrun. Motivation, health status and benefits were compared for sub-groups defined by physical activity level at parkrun registration and residential Index of Multiple Deprivation. RESULTS: 60,000 completed surveys were received (2.7% of those contacted). Respondents were more recently registered with parkrun (3.1 v. 3.5 years) than the parkrun population and had a higher frequency of parkrun participation (14.5 v. 3.7 parkruns per year). Those inactive at registration and from deprived areas reported lower happiness, lower life satisfaction and poorer health compared to the full sample. They were more likely to want to improve their physical health, rather than get fit or for competition. Of those reporting less than one bout of activity per week at registration, 88% (87% in the most deprived areas) increased their physical activity level and 52% (65% in the most deprived areas) reported improvements to overall health behaviours. When compared to the full sample, a greater proportion of previously inactive respondents from the most deprived areas reported improvements to fitness (92% v. 89%), physical health (90% v. 85%), happiness (84% v. 79%) and mental health (76% v. 69%). CONCLUSION: The least active respondents from the most socioeconomically deprived areas reported increases to their activity levels and benefits to health and wellbeing since participating in parkrun. Whilst the challenge of identifying how community initiatives like parkrun can better engage with underrepresented populations remains, if this can be achieved they could have a critical public health role in addressing inequalities in benefits associated with recreational physical activity.

Engaging people with long-term health conditions in a community-based physical activity initiative: a qualitative follow-up study evaluating the parkrun PROVE project.

BACKGROUND: The "parkrun: running or volunteering for everyone" (PROVE) project was an example of a community-based physical activity and volunteering initiative for people living with long-term health conditions in England. The 3 year project involved appointing volunteer Outreach Ambassadors whose role was to promote parkrun to people living with long-term health conditions through various outreach activities. This qualitative study aimed to understand the experience of delivering the project from the perspective of volunteer Outreach Ambassadors and the PROVE Project Manager. METHODS: The PROVE Project Manager and ten PROVE Outreach Ambassadors across nine health condition groups were interviewed by the researcher (asthma, blood pressure, deaf and hard of hearing, dementia, diabetes, endometriosis, heart conditions, learning disabilities and/or autism, and obesity). Interview transcripts were analysed using thematic analysis. RESULTS: Four themes and nine sub-themes were generated. The participants highlighted challenges in measuring the project's success and bringing about meaningful and lasting change, and reflected on the value of the project as a learning opportunity. Despite some successes, it was thought that the project had limited reach outside of the existing parkrun community. The Outreach Ambassadors reflected on their experiences in the role and the skills required, finding it rewarding and highlighting the importance of networking and forming connections with key stakeholders. The findings are discussed in comparison to interviews conducted with the Outreach Ambassadors 12 months earlier. CONCLUSIONS: This study provides evidence to support the public health potential of parkrun though targeted initiatives such as the PROVE project and provides a critical reflection on what worked and what did not work when delivering the project. The findings have relevance for organisations wishing to implement similar outreach initiatives using a volunteer workforce, including recommendations for resource management, communication, leadership, fostering volunteer autonomy and defining and capturing success.

Socioeconomic inequalities in distance to and participation in a community-based running and walking activity: A longitudinal ecological study of parkrun 2010 to 2019.

OBJECTIVES: To conduct a longitudinal ecological analysis of the distance to and participation in free weekly outdoor physical activity events (parkrun) in England from 2010 to 2019, and related socioeconomic and ethnic inequalities, to inform policies to support participation in physically active community events. METHODS: We calculate distance to the nearest parkrun event for each English Lower Layer Super Output Area (LSOA) each month from January 2010 to December 2019. We then report the trends in distance to and participation in parkrun by Index of Multiple Deprivation quintile. We also report trends in the Relative Index of Inequality (RII) by deprivation for participation and distance to nearest event. We go on to investigate trends in LSOA level determinants (e.g. deprivation and ethnic density) of parkrun participation between 2010 and 2019, using multivariable Poisson regression models. RESULTS: Mean distance to the nearest parkrun event decreased from 34.1 km in 2010, to 4.6 km in 2019. Throughout the period, parkrun events tended to be situated closer to deprived areas compared to less deprived areas. Participation rates increased superlinearly (greater than linear increase) from 2010 to 2013 before slowing to linear growth. Participation over the period exhibits a clear socioeconomic gradient, with people from deprived areas having consistently lower participation rates over the period. parkrun participation rates became more equal between 2010 and 2013 (RII improved from 189 to 39), before stabilising at an RII between 32.9 and 39.6 from 2014 to 2019. The results of the Poisson regression model validate this finding; the coefficients on IMD score initially increased from -0.050 in 2010 to -0.038 in 2013, and then remained relatively stable to 2019 (-0.035). CONCLUSIONS: Over the past 10 years, geodesic distance to the nearest parkrun decreased from a mean of 34 km to 5 km. In 2010, there was equality between the least and most deprived areas but by 2017 the distance of the most deprived areas was 29% that of the least deprived. Participation was shown to have increased over the past 10 years which can be split into two distinct phases: from 2010 to 2013 participation increased super-linearly and inequality in participation fell dramatically; from 2013 to 2019 participation increased linearly, and inequality in participation remained stable. Despite parkrun's ambitions of creating inclusive events and engaging with deprived communities, the socioeconomic gradient in participation rates remained high and stable since 2013. Gaining a better understanding of the reasons why parkrun grew so quickly may be useful for other physical activity movements, while further analysis of the relatively lower participation rates in areas with higher socioeconomic deprivation is important for developing initiatives to encourage physical activity in these communities.

Does ethnic density influence community participation in mass participation physical activity events? The case of parkrun in England.

Background: parkrun has been successful in encouraging people in England to participate in their weekly 5km running and walking events. However, there is substantial heterogeneity in parkrun participation across different communities in England: after controlling for travel distances, deprived communities have significantly lower participation rates. Methods: This paper expands on previous findings by investigating disparities in parkrun participation by ethnic density. We combined geo-spatial data available through the Office for National Statistics with participation data provided by parkrun, and fitted multivariable Poisson regression models to study the effect of ethnic density on participation rates at the Lower layer Super Output Level. Results: We find that areas with higher ethnic density have lower participation rates. This effect is independent of deprivation. Conclusions: An opportunity exists for parkrun to engage with these communities and reduce potential barriers to participation.

How can we get more people with long-term health conditions involved in parkrun? A qualitative study evaluating parkrun's PROVE project.

BACKGROUND: People with long-term health conditions face barriers to physical activity and community health interventions despite potential life-changing benefits for self-management of their condition and wellbeing. A weekly mass participation running, walking and volunteering event called parkrun launched a project called PROVE in 2016 to engage people living with long-term health conditions in England. Over the 3 year project, parkrun appointed volunteer Outreach Ambassadors with a specialist interest in the health condition they represented whose role was to ensure parkrun was welcoming, supportive and inclusive. This qualitative study aimed to understand the experience of the PROVE project for people with long-term health conditions. METHODS: Semi-structured interviews were conducted with 15 PROVE Outreach Ambassadors representing 13 different long-term health conditions in England. Interviews were recorded, transcribed verbatim and analysed using thematic analysis. Rigour and transparency were sought in addition to utilising independent researchers to offer alternative interpretations of the data. RESULTS: Data analysis resulted in 4 overarching themes and 13 subthemes. Outreach Ambassadors believed that parkrun was already supportive of people with long-term health conditions, but that the PROVE project enabled the support to be delivered in a more structured way across health conditions and locations. Outreach Ambassadors believed that the PROVE project had the potential to create a welcoming, safe space for people with long-term health conditions to participate as walkers, runners or volunteers. Success of the PROVE project was believed to be dependent on being realistic about the potential to bring about change, challenging people's perceptions of parkrun and engaging with key stakeholders and advocacy groups. Challenges for parkrun were believed to be around communication, demonstrating impact and the project's dependence on volunteers for delivery. CONCLUSIONS: This is the first study of its kind to explore the public health potential of parkrun for people with long-term health conditions. parkrun's PROVE project was regarded to be important for ensuring that people with long-term health conditions can engage in physical activity and volunteering in a safe and supportive environment. The findings have important implications for parkrun, policy makers and physical activity providers looking to deliver inclusive community physical activity opportunities.

Quantification of gravity-induced skin strain across the breast surface.

BACKGROUND: Quantification of the magnitude of skin strain in different regions of the breast may help to estimate possible gravity-induced damage whilst also being able to inform the selection of incision locations during breast surgery. The aim of this study was to quantify static skin strain over the breast surface and to estimate the risk of skin damage caused by gravitational loading. METHODS: Fourteen participants had 21 markers applied to their torso and left breast. The non-gravity breast position was estimated as the mid-point of the breast positions in water and soybean oil (higher and lower density than breast respectively). The static gravity-loaded breast position was also measured. Skin strain was calculated as the percentage extension between adjacent breast markers in the gravity and non-gravity loaded conditions. FINDINGS: Gravity induced breast deformation caused peak strains ranging from 14 to 75% across participants, with potentially damaging skin strain (>60%) in one participant and skin strains above 30% (skin resistance zone) in a further four participants. These peak strain values all occurred in the longitudinal direction in the upper region of the breast skin. In the latitudinal direction, smaller-breasted participants experienced greater strain on the outer (lateral) breast regions and less strain on the inner (medial) breast regions, a trend which was reversed in the larger breasted participants (above size 34D). INTERPRETATION: To reduce tension on surgical incisions it is suggested that preference should be given to medial latitudinal locations for smaller breasted women and lateral latitudinal locations for larger breasted women.

Embedding Physical Activity in the Heart of the NHS: The Need for a Whole-System Approach.

Solutions to the global challenge of physical inactivity have tended to focus on interventions at an individual level, when evidence shows that wider factors, including the social and physical environment, play a major part in influencing health-related behaviour. A multidisciplinary perspective is needed to rewrite the research agenda on physical activity if population-level public health benefits are to be demonstrated. This article explores the questions that this raises regarding the particular role that the UK National Health Service (NHS) plays in the system. The National Centre for Sport and Exercise Medicine in Sheffield is put forward as a case study to discuss some of the ways in which health systems can work in collaboration with other partners to develop environments and systems that promote active lives for patients and staff.

An improvement index to quantify the evolution of performance in field events.

The mean of the top 25 performances in 8 men's and 5 women's field events since the 1890s showed that performances increased dramatically after the Second World War II and subsequently plateaued during the late twentieth century. A performance improvement index, developed on the basis of work done, was set to 100% in 1948. The underlying rise found in all events was modelled using an exponential function with a superposition of steps and linear changes to account for the introduction of rule changes, drugs testing and the introduction of new technologies. The performance improvement index in throwing events increased to 140.9% compared with 125.8% in jumping events, and women's performance improvement always exceeded that of men's. Around half of all events were shown to have reached 99.9% of their predicted limit with a majority reaching it within the next 25 years. It was concluded that performance will only change in the future if an intervention takes place: this could be the emergence of a new technology, a rule change or a new athlete population.

An improvement index to quantify the evolution of performance in running.

Improvements in track and field sports have been attributed to factors such as population increase, drugs and new technologies, but previous research has found it difficult to distinguish the contributions from specific influences. Here it is shown how this is possible by means of a performance improvement index based on useful work done combined with modelling of the annual top 25 performances. The index was set to 100 in 1948 and showed that, by 2012, it had increased in running events to between 110.5 and 146.7 (men's 100 m and marathon). Underlying global effects accounted for the majority of all improvements (16.2 to 46.7) with smaller influences attributable to an influx of African runners (3.6 to 9.3), and a 4-year oscillation that arose from staging of the Olympic Games (±0.2 to ±0.6). Performance decreased with the introduction of compulsory random drug testing (-0.9 to -3.9) the World Anti-Doping Agency (WADA; -0.5 to -2.5) and fully automated timing (-0.6 to -2.5). Changes in elite sporting performance since the 1890s are attributable to societal changes caused by the industrial revolution and globalisation superimposed on millennia of human evolution.

Effect of tennis racket parameters on a simulated groundstroke.

Composite materials have given manufacturers the freedom to develop a broad range of tennis rackets, allowing them to change key parameters such as the structural stiffness, mass, and position of the balance point. The aim of this research was to determine how changing these parameters could affect ball resultant rebound velocity and spin for a simulated groundstroke. A finite element model of a freely suspended racket and strings was used to determine the effect of racket parameters for oblique spinning impacts at a range of locations on the stringbed. The finite element simulations were conducted in the laboratory frame of reference, where the ball is projected onto an initially stationary racket. The mean rebound velocity of the ball was 9% higher for a structurally stiff racket, 37% higher for a heavy racket, and 32% higher for a head-heavy racket. In addition, the mean rebound topspin of the ball was 23% higher for a heavy racket and 21% higher for a head-heavy racket. Therefore, in relation to a groundstroke with an impact location away from the node, the rebound velocity of the ball is likely to increase with the structural stiffness of a racket. The effect of changing the mass and position of the balance point is more complex, as it is dependent on the relationship between the transverse moment of inertia and maximum pre-impact swing velocity.