The science of sports surface interactions for synthetic turf surfaces

The introduction and acceptance of new (3rd) generation long pile filled synthetic turf surfaces in sports such and football and rugby has led to these surfaces becoming widely used at all levels of the game. The interaction of a sports person and/or ball with these surfaces is of great importance in terms of player safety, comfort and playing performance. The specification for these surfaces, and the constituent materials used, are known to vary within the industry. Recent field measurements of unfilled ‘water based’ pitches highlighted significant spatial and temporal changes in the playing characteristics both over the surface of a single pitch and between (similar) pitches, including the test results for traction. It has been suggested that synthetic turf surfaces increase the traction produced at the shoe-surface interface causing a greater number of sports specific injuries. However, as part of a PhD research programme at Loughborough University, a comprehensive review of published literature was performed which highlighted a significant lack of quantified research and data regarding the surface properties influencing the traction developed at the shoe-surface interface. There has been no attempt to date to measure and quantify the role of the individual components of a surface on the traction that can be achieved. If the underlying material science of the surface components were better understood, decisions and judgements based on the desired characteristics required for surfaces could be optimised. This paper reviews the available information regarding 3rd generation synthetic turf surfaces and establishes the primary parameters influencing traction during the interaction between a player and the surface, with a focus on the mechanics of the surface components and their interaction, and the influence of potential changes during the pitch lifetime, such as degradation. The proposed research and methods required to address these knowledge gaps is presented

Design and development of a novel natural turf shear stability tester

The stability of natural Rugby Union pitches continues to be a recurring problem at all levels of the game. The effects of poor stability are seen when the pitch surface shears under player loading, creating unsightly divots and an uneven and potentially injurious surface. This observed instability is a real concern for many stakeholders, from the groundsmen to the revenue-generating television companies, and is arguably increasing caused by greater popularity of sports, more intensive use of natural turf pitches and advances in player physical conditioning. However, perhaps surprisingly, no objective quantitative mechanical test method currently exists for assessing the shear stability of the natural turf prior to games being played. This paper presents the findings from a (ongoing) research study into the design and development of a prototype turf stability apparatus (‘Turf Tester’). The key aim was to measure the shearing stability of natural and hybrid turf in order to assess a recurring failure problem. In order to be relatable to sporting performance, this failure imitates conditions to simulate player(s) interaction. The prototype and test method was developed with properties suggested from published papers discussing rugby and agronomists’ experience. It was theorized that there was a potential zone susceptible to failure within the top 100 mm of the sports turf. The position of this zone was variable and depended on pitch construction. The prototype was built to explore this variable failure zone using a 50 mm and 100 mm pin that sheared through the soil when a known load was applied to it. Both the Clegg Impact Hammer (CIH) and the rotational traction (RTD) were suggested to be relatable to penetration and shear stability; however, their relatability to the failure zone was an unknown. This paper details the background behind the study, the prototype design and principle, the observed failure mechanisms of sports turf, and presents the results of the prototype apparatus trailed on a range of turf constructions at venues used for the 2015 Rugby World Cup. Data was collected at each venue using Labosport’s Scoreplay system detailing full agronomic classifications and a suite of industry standard player performance tests. The combined data from 13 of the venues provided a powerful data set to evaluate and refine the prototype apparatus, providing validity of its conceptual design. The findings show that the shear tester assessed the upper level of ability of pitches with a 50 mm depth pin and the lower ability with the 100 mm pin. There was some evidence of a relationship to the CIH and RTD, albeit weak, and it was concluded the shear tester was assessing a characteristic of the sport turf not currently measured by standard industry tests currently utilized. The shear tester differentiated between the high stability of the hybrid pitch constructions and the weaker natural pitches. The shear tester rankings for pitch quality also approximated well the ranking from the Scoreplay pitch quality system. Incorporation of the shear tester into routine pitch evaluations could benefit a scoring system approac

Novel field equipment for assessing the stability of natural and hybrid turfs

Natural turf pitches are used for many outdoor sports. Turf is a complex network of interacting organic material, soil textures and water content. Turf is susceptible to damage under large surface forces, caused by intensive player movements in rugby union and football. To assess and monitor surface stability, there needs to be a reliable test method for ground staff and other stakeholders. At present, no turf stability mechanical test method exists that represents player–surface interaction, especially to represent a linear movement across the surface such as in a rugby scrummage. This paper describes the development of a novel device for assessing turf stability. Verification was undertaken in the laboratory on a variety of controlled soil samples, and during a field study. The device measurements were shown to be sensitive to the shear strength of a high clay content soil at varying water content and to the density and type of sandy soils. A programme of field data on high quality pitches suggested a large effect of the turf root reinforcement. A conceptual model of soil failure induced by the device was developed to identify the key soil variables and support experimental data interpretation

Investigating shear stability of rugby union natural turf pitches

The stability of natural Rugby Union pitches continues to be a recurring problem at all levels of the game. The effects of poor turf stability are seen when the pitch surface shears under player loading, creating divots and an uneven surface. However, perhaps surprisingly, there is no objective quantitative mechanical test method for assessing the stability of the natural turf, with regard to shear resistance. This paper details initial work undertaken to assess the effectiveness of current shear testing apparatus in predicting stability for Rugby Union. It has been suggested there are two failure areas in pitch constructions: One on the surface and one deeper in the soil. The results show variability in natural turf constructions, and that current shear test methods are less effective in sandy soils. Penetration readings were relatable to hardness, however shear stability testing requires development

Investigating shear stability of rugby union natural turf pitches

The stability of natural Rugby Union pitches continues to be a recurring problem at all levels of the game. The effects of poor turf stability are seen when the pitch surface shears under player loading, creating divots and an uneven surface. However, perhaps surprisingly, there is no objective quantitative mechanical test method for assessing the stability of the natural turf, with regard to shear resistance. This paper details initial work undertaken to assess the effectiveness of current shear testing apparatus in predicting stability for Rugby Union. It has been suggested there are two failure areas in pitch constructions: One on the surface and one deeper in the soil. The results show variability in natural turf constructions, and that current shear test methods are less effective in sandy soils. Penetration readings were relatable to hardness, however shear stability testing requires development

Design and development of a novel natural turf shear stability tester

The stability of natural Rugby Union pitches continues to be a recurring problem at all levels of the game. The effects of poor stability are seen when the pitch surface shears under player loading, creating unsightly divots and an uneven and potentially injurious surface. This observed instability is a real concern for many stakeholders, from the groundsmen to the revenue-generating television companies, and is arguably increasing caused by greater popularity of sports, more intensive use of natural turf pitches and advances in player physical conditioning. However, perhaps surprisingly, no objective quantitative mechanical test method currently exists for assessing the shear stability of the natural turf prior to games being played. This paper presents the findings from a (ongoing) research study into the design and development of a prototype turf stability apparatus (‘Turf Tester’). The key aim was to measure the shearing stability of natural and hybrid turf in order to assess a recurring failure problem. In order to be relatable to sporting performance, this failure imitates conditions to simulate player(s) interaction. The prototype and test method was developed with properties suggested from published papers discussing rugby and agronomists’ experience. It was theorized that there was a potential zone susceptible to failure within the top 100 mm of the sports turf. The position of this zone was variable and depended on pitch construction. The prototype was built to explore this variable failure zone using a 50 mm and 100 mm pin that sheared through the soil when a known load was applied to it. Both the Clegg Impact Hammer (CIH) and the rotational traction (RTD) were suggested to be relatable to penetration and shear stability; however, their relatability to the failure zone was an unknown. This paper details the background behind the study, the prototype design and principle, the observed failure mechanisms of sports turf, and presents the results of the prototype apparatus trailed on a range of turf constructions at venues used for the 2015 Rugby World Cup. Data was collected at each venue using Labosport’s Scoreplay system detailing full agronomic classifications and a suite of industry standard player performance tests. The combined data from 13 of the venues provided a powerful data set to evaluate and refine the prototype apparatus, providing validity of its conceptual design. The findings show that the shear tester assessed the upper level of ability of pitches with a 50 mm depth pin and the lower ability with the 100 mm pin. There was some evidence of a relationship to the CIH and RTD, albeit weak, and it was concluded the shear tester was assessing a characteristic of the sport turf not currently measured by standard industry tests currently utilized. The shear tester differentiated between the high stability of the hybrid pitch constructions and the weaker natural pitches. The shear tester rankings for pitch quality also approximated well the ranking from the Scoreplay pitch quality system. Incorporation of the shear tester into routine pitch evaluations could benefit a scoring system approac

Comparative Judgement Modeling to Map Forced Marriage at Local Levels

Forcing someone into marriage against their will is a violation of their human rights. In 2021, the county of Nottinghamshire, UK, launched a strategy to tackle forced marriage and violence against women and girls. However, accessing information about where victims are located in the county could compromise their safety, so it is not possible to develop interventions for different areas of the county. Comparative judgement studies offer a way to map the risk of human rights abuses without collecting data that could compromise victim safety. Current methods require studies to have a large number of participants, so we develop a comparative judgement model that provides a more flexible spatial modelling structure and a mechanism to schedule comparisons more effectively. The methods reduce the data collection burden on participants and make a comparative judgement study feasible with a small number of participants. Underpinning these methods is a latent variable representation that improves on the scalability of previous comparative judgement models. We use these methods to map the risk of forced marriage across Nottinghamshire thereby supporting the county's strategy for tackling violence against women and girls.Comment: Submitted. 31 pages, 8 figure

No overall change in the rate of weight gain after switching to an integrase-inhibitor in virologically suppressed adults with HIV

OBJECTIVE: Excessive weight gain has been reported with integrase strand transfer inhibitors (INSTIs). We evaluated weight changes in virologically-suppressed adults with HIV who switched from non-INSTI regimens to raltegravir- or dolutegravir-containing antiretroviral therapy. DESIGN: Retrospective single-centre cohort. METHODS: Adults who switched to raltegravir or dolutegravir before or between January-2015 and October-2017 were identified. Virologically-suppressed, treatment-experienced (≥2 years) individuals, ≥6 months on INSTI, with weight measurements ≤2years pre- and post-switch were included. Our analysis used a random effects model with linear slope pre- and post-INSTI with adjustment for age, gender, ethnicity, pre-switch-regimen (protease inhibitor vs. non-protease inhibitor), and raltegravir vs. dolutegravir use. RESULTS: 378 individuals, 81.2% male, 70.1% white ethnicity, median age of 49 years, median of four weight measurements per participant, and median weight and body mass index (BMI) at switch, of 76.6 kg, and 25.3 kg/m respectively were included. Weight increased by an average of 0.63 kg/year (95% CI 0.17-1.09) pre-switch with no overall change in rate of weight gain post-switch [+0.05 kg/year (-0.61-0.71, p = 0.88)]. In our adjusted model, a transition from minimal weight change to weight gain post-switch was isolated to older individuals though this lacked statistical significance [e.g. +1.59 kg/year (-0.26-3.45) if aged 65 years]. Our findings did not differ by gender, ethnicity, pre-switch regimen, or raltegravir vs. dolutegravir. Similar results were seen for BMI and after adjusting for fixed nucleoside/nucleotide reverse transcriptase inhibitor backbone. CONCLUSION: We found no clear evidence of an overall increase in rate of weight gain following switch to INSTI in virologically-suppressed individuals

Ex vivo culture of adult CD34+ stem cells using functional highly porous polymer scaffolds to establish biomimicry of the bone marrow niche

Haematopoiesis, the process of blood production, occurs from a tiny contingent of haematopoietic stem cells (HSC) in highly specialised three-dimensional niches located within the bone marrow. When haematopoiesis is replicated using in vitro two-dimensional culture, HSCs rapidly differentiate, limiting self-renewal. Emulsion-templated highly porous polyHIPE foam scaffolds were chosen to mimic the honeycomb architecture of human bone. The unmodified polyHIPE material supports haematopoietic stem and progenitor cell (HSPC) culture, with successful culture of erythroid progenitors and neutrophils within the scaffolds. Using erythroid culture methodology, the CD34+ population was maintained for 28 days with continual release of erythroid progenitors. These cells are shown to spontaneously repopulate the scaffolds, and the accumulated egress can be expanded and grown at large scale to reticulocytes. We next show that the polyHIPE scaffolds can be successfully functionalised using activated BM(PEG)2 (1,8-bismaleimido-diethyleneglycol) and then a Jagged-1 peptide attached in an attempt to facilitate notch signalling. Although Jagged-1 peptide had no detectable effect, the BM(PEG)2 alone significantly increased cell egress when compared to controls, without depleting the scaffold population. This work highlights polyHIPE as a novel functionalisable material for mimicking the bone marrow, and also that PEG can influence HSPC behaviour within scaffolds

The use of a pre-operative scoring system for the prediction of phacoemulsification case difficulty and the selection of appropriate cases to be performed by trainees

Background: To establish whether a previously validated scoring system (Habib) for the prediction of risk or likelihood of posterior capsule rupture during phacoemulsification surgery could be used to: 1. Predict the difficulty of a phacoemulsification case, and 2. Select appropriate phacoemulsification cases for trainees. Methods: The study sample was consecutive phacoemulsification cases undertaken by senior surgeons at a single ophthalmic unit over a three-week period (170 cases). Each case was scored using a potential difficulty scoring system. Immediately post-operatively, each case was given two scores by the operating surgeon (who was masked with regard to the potential complication score). The first score indicated the perceived difficulty of the case, and the second score, the degree of experience that they thought a trainee would require in order to have performed the same case without complication. Results: Using Cuzick's non-parametric test for trend, there was evidence for a trend of increasing perceived difficulty with increasing potential difficulty score (p = 0.05), and of increasing experience required with increasing potential difficulty score (p < 0.001) Conclusion: The authors advocate that Habib's potential difficulty scoring system can be used to inform the surgeon of the likely difficulty of a phacoemulsification case and to aid selection of appropriate cases for trainees prior to surgery