High Concussion Rate in Student Community Rugby Union Players During the 2018 Season: Implications for Future Research Directions

Collision sports, such as Rugby Union (“Rugby”) have a particularly high risk of injury. Of all injuries common to collision sports, concussions have received the most attention due to the potentially negative cognitive effects in the short- and long-term. Despite non-professional Rugby players comprising the majority of the world’s playing population, there is relatively little research in this population. Stellenbosch Rugby Football Club (“Maties”), the official rugby club of Stellenbosch University, represents one of the world’s largest non-professional Rugby clubs, making this an ideal cohort for community-level injury surveillance. The aim of this study was to describe the incidence and events associated with concussion in this cohort. Baseline demographics were obtained on the 807 male student Rugby non-professional players who registered for the 10-week long 2018 season, which comprised 101 matches and 2,915 of exposure hours. All match-related injuries were captured by the medical staff of Stellenbosch Campus Health Service on an electronic form developed from the consensus statement for injury recording in Rugby. The mean age, height and weight of this cohort were 20 ± 2 years, 182 ± 7 cm and 88 ± 14 kg, respectively

Magnetic resonance imaging detects placental hypoxia and acidosis in mouse models of perturbed pregnancies

Endothelial dysfunction as a result of dysregulation of anti-angiogenic molecules secreted by the placenta leads to the maternal hypertensive response characteristic of the pregnancy complication of preeclampsia. Structural abnormalities in the placenta have been proposed to result in altered placental perfusion, placental oxidative stress, cellular damage and inflammation and the release of anti-angiogenic compounds into the maternal circulation. The exact link between these factors is unclear. Here we show, using Magnetic Resonance Imaging as a tool to examine placental changes in mouse models of perturbed pregnancies, that T2 contrast between distinct regions of the placenta is abolished at complete loss of blood flow. Alterations in T2 (spin-spin or transverse) relaxation times are explained as a consequence of hypoxia and acidosis within the tissue. Similar changes are observed in perturbed pregnancies, indicating that acidosis as well as hypoxia may be a feature of pregnancy complications such as preeclampsia and may play a prominent role in the signalling pathways that lead to the increased secretion of anti-angiogenic compounds

Stakeholder perceptions of a tackle law variation to reduce concussion incidence in community rugby union: A qualitative study

This study aimed to investigate the perceptions of key stakeholder groups, i.e. coaches, players, and referees, of a reduced maximum legal tackle height law variation trial in a collegiate amateur rugby competition. A pragmatic qualitative approach was used. Eighteen semi-structured interviews were performed. Thematic analysis was used to analyse the data. Three main law trial-related themes and four additional contextual themes were identified. The most important contextual factors include perceptions of resource scarcity of the implementation context, deficient concussion knowledge and lack of education among all stakeholder groups, tackle technique deficiencies, and an entrenched culture of a dismissive attitude towards serious injuries and non-disclosure of concussion by players. Real-world challenges such as inconsistent sanctioning during gameplay, multi-tackler tackles, and player fatigue underscore the gap between the theoretical knowledge of the law and the complex, dynamic nature of its execution. Furthermore, deeply ingrained issues like entrenched tackle techniques, the quality of coaching, and prevailing attitudes towards concussion compounded these challenges, indicating a need for a more comprehensive approach to bridge the divide between understanding and implementation. Despite these challenges, several participants felt the law variation was still more effective than the existing law; and that it created more awareness around concussion, while sending a clear message that player welfare is being taken seriously. Collectively these factors indicate the difficulty of addressing a complex problem such as concussion, with a law variation intervention in a challenging (resource-constrained) setting

Tackling sport-related concussion: effectiveness of lowering the maximum legal height of the tackle in amateur male rugby - a cross-sectional analytical study

OBJECTIVE: Rugby union ('rugby') is popular globally, with most of its participants being amateur. Concern regarding sport-related concussion (SRC) sustained during rugby is increasing. SRC occurs most frequently in the tackle, yet few interventions have aimed to mitigate this risk factor. This study investigated the influence of a lowered legal tackle height on SRC incidence in amateur rugby. DESIGN: Cross-sectional analytical study: 2018 (control-standard tackle height) and 2019 (intervention-lowered legal tackle height) seasons. SETTING: South African collegiate student rugby competition. PARTICIPANTS: Between 800 and 900 male amateur student players (age: 20±1.6 years) in each year. INTERVENTION: Maximum legal tackle height lowered from line of the shoulder on the ball carrier to the line of the armpit. OUTCOME MEASURES: Number of overall (medical attention) and time-loss (≥1 day lost) injuries, head injuries and SRCs in 2018 and 2019 (dependent variables); events associated with injury incidents (independent variables). RESULTS: There was no statistically significant difference in incidences of time-loss injuries (IRR: 0.79; 95% CI: 0.6 to 1.1; p=0.13), head injuries (IRR: 0.83; 95% CI: 0.5 to 1.3; p=0.42) and SRC (IRR: 0.69; 95% CI: 0.4 to 1.2; p=0.20). In 2018 and 2019, most time-loss head injuries (57%, n=43) and SRCs (55%, n=26) occurred during the tackle. CONCLUSIONS: Despite a trend towards reducing injuries, head injuries and SRC, lowering maximum legal tackle height to armpit level did not change SRC incidence in this amateur male rugby cohort. Most time-loss head injuries and SRCs occurred during the tackle. Further tackle-related interventions to reduce SRC incidence require investigation

Automated analysis of soft material microindentation

An understanding of the mechanical properties of soft hydrogel materials over multiple length scales is important for their application in many fields. Typical measurement methods provide either bulk mechanical properties (compression, tensile, rheology) or probing of nano or microscale properties and heterogeneity (nanoindentation, AFM). In this work we demonstrate the complementarity of instrumented microindentation to these techniques, as it provides representative Young's moduli for soft materials with minimal influence of the experimental parameters chosen, and allows mechanical property mapping across macroscopic areas. To enable automated analysis of the large quantities of data required for these measurements, we develop a new fitting algorithm to process indentation data. This method allows for the determination of Young's moduli from imperfect data by automatic selection of a region of the indentation curve which does not display inelastic deformation or substrate effects. We demonstrate the applicability of our approach with a range of hydrogels, including materials with patterns and gradients in stiffness, and expect the techniques described here to be useful developments for the mechanical analysis of a wide range of soft and biological systems

Tackling the tackle 2: Evaluation of referee and player behavioural change as measures of implementation of a law variation in community-level male amateur rugby union.

OBJECTIVES: To evaluate player and referee behaviour during a lower tackle height law variation trial in community rugby union ('rugby'). DESIGN: Prospective observational cohort study. METHODS: In a law variation trial in male amateur community rugby, coded match video surveillance data were analysed. Referee (sanctioning rate) and player (tackler body position) behaviour changes over one season (under the lowered, armpit-level maximum legal tackle height condition) were analysed in three approximately equal periods of the season. Secondarily, an independent professional referee reviewed illegal high tackle sanctioning data. RESULTS: Overall, 108 matches with 14,780 tackles were filmed and coded. Sanctioned illegal high tackle propensity was significantly higher in the mid-season (41 sanctioned high tackles/1000 tackle events; 95 % CI: 35-47), compared with first and last periods. Upright tacklers in tackles decreased significantly in the final vs. middle period of the season (rate ratio: 0.69; 95 % CI: 0.54-0.88; p < 0.01). Of all the coder-determined high tackles also assessed as high under the new law by the independent referee, 51 % were sanctioned by the on-field referee. CONCLUSIONS: Positive player and referee behavioural changes were observed during a lowered legal tackle height law variation in this community rugby setting. Increased mid-phase high tackle sanctioning by referees was followed by fewer tackles with upright tacklers in the subsequent (last) phase of the season. Encouraging positive behaviour changes of this nature, particularly if sustained (beyond trial study periods), may contribute to overall injury risk reduction, and hold considerable importance to inform future injury prevention strategies in rugby

Tackling the tackle 1: a descriptive analysis of 14,679 tackles and risk factors for high tackles in a community-level male amateur rugby union competition during a lowered tackle height law variation trial

Objective In rugby union (rugby), the tackle is the most frequent cause of concussion and thus a target for intervention to reduce concussion incidence. The aim of this study is to describe tackle characteristics and factors associated with illegal high tackles in amateur community-level rugby during a lowered (arm-pit level) tackle height law variation trial. Design Prospective observational cohort study. Methods Video surveillance of a single season, four-league competition with coding of video data according to a predefined coding framework. Descriptive statistics of tackle detail and logistic regression was performed to analyse factors associated with high tackles. Results One hundred and eight matches with 14,679 tackles and a mean of 137 (± 30) tackles per match were analysed. High tackles (above armpit-level) had significantly greater odds of occurring in the lower (2nd-4th) leagues (OR: 1.95; 95 % CI: 1.6–2.4; p < 0.001), front-on tackles (OR: 1.61; 95 % CI: 1.3–2.0; p < 0.001), arm tackles (OR: 1.65; 95 % CI: 1.3–2.1; p < 0.001), bent-at-waist ball carrier (OR: 1.93; 95 % CI: 1.6–2.4; p < 0.001), falling/diving ball carrier (OR: 2.21; 95 % CI: 1.6–3.1; p < 0.001), and an upright tackler (OR: 3.38; 95 % CI: 2.7–4.2; p < 0.001). A falling/diving tackler had significantly lower odds of being associated with a high tackle (OR: 0.44; 95 % CI: 0.3–0.6; p < 0.001). Conclusions Overall mean tackles per match was similar to that of senior amateur and elite rugby. League, tackle type, tackle aspect, and player body positions were associated with high tackles. These findings reiterate the need for ongoing efforts to identify and implement mitigating strategies to reduce tackle-related injury risk

Magnetic resonance imaging measurements of T2 relaxation times within contrasting regions of murine placenta is dependent upon blood flow

Introduction: It has been postulated that reduced placental perfusion as a result of abnormal placental implantation is the initiating event that leads to the maternal symptoms of preeclampsia. To be able to directly measure blood flow and perfusion in the placenta in experimental models of preeclampsia would provide valuable insight into the structural abnormalities of this syndrome. Magnetic resonance imaging (MRI) offers visualization of anatomy and analysis of changes in tissue morphology and function including blood flow and perfusion. The major source of image contrast in MRI comes from the variation in relaxation times between tissues. Previously, human placenta has appeared as fairly homogeneous in studies of T1 and T2 relaxation times, with no internal morphology apparent. Objectives: The aim of this study was to investigate, using much higher field strengths (11.7 Tesla) and much higher resolution than have been used previously, whether structural inhomogeneities in the placenta can be discerned by T2 mapping and whether T2 mapping is capable of detecting structural abnormalities that may affect blood flow in a preeclamptic placenta

Morphological differences in murine placenta detected by magnetic resonance imaging measurements of T2 relaxation times in mouse models of preeclampsia

Introduction: We have demonstrated that morphologically distinct regions of the murine placenta can be detected by magnetic resonance imaging (MRI), with image contrast arising from the variation in T2 relaxation times between regions and dependent upon blood flow. Previous studies of human placenta by other groups have shown a homogeneous tissue with correlation of relaxation times with gestational age and a trend for shorter relaxation times in pregnancies complicated by preeclampsia and fetal growth restriction. The ability to detect morphological changes and alterations in blood flow in experimental models of preeclampsia would be a significant boost in understanding the relationship between abnormal placental implantation, reduced placental perfusion, inflammatory cytokines, angiogenic molecules and other factors that may play a role in the syndrome. Objectives: The aim of this study was to investigate whether morphological changes or abnormalities can be detected by T2 mapping in the placenta of mice subject to two experimental models of preeclampsia (reduced uterine perfusion pressure (RUPP) model and TNF-a induced model)