Rugby Science Update 12

Cardiovascular risk and systemic inflammation in male professional rugby: a cross-sectional study

The aim of this study was to characterize cardiovascular risk factors, including markers of inflammation, in professional rugby players based on their position. Furthermore, the study compared inflammatory markers in rugby players to those in healthy controls and patients with rheumatoid arthritis (RA). All professional rugby players (n=46) were free from injury and illness at the time of data collection. The rugby players were then categorized by position; forwards (n=21) and backs (n=25). All data collections were collected during the pre-season. Markers of inflammation for the healthy controls and RA patients were obtained from a biobank database at Trinity Biomedical Sciences Institute. Most rugby players in this study exhibited at least one cardiovascular risk factor. Forwards had higher values for all body composition variables, C-reactive protein (CRP) and glucose compared to backs. The rugby player cohort overall showed increased levels of systemic inflammation. One-third of the cohort displayed similarity in inflammation levels to patients with chronic inflammatory diseases. The authors note that the sample size is too small to generalize findings. However, there is a risk of hypertension and dyslipidaemia that should be screened for in rugby players.

This study is published in BMJ Open Sport & Exercise Medicine.

McHugh C, Hind K, Kelly A, et al Cardiovascular risk and systemic inflammation in male professional rugby: a cross-sectional study BMJ Open Sport & Exercise Medicine 2023;9:e001636. doi: 10.1136/bmjsem-2023-001636

Incidence of concussion in men’s Super League, Championship, and Academy rugby league matches between 2016 and 2022

The purpose of this study was to describe the incidence of concussion in the male rugby league at Super League, Championship, and Academy levels between 2016 and 2022. All rugby league medical teams must complete and submit a concussion report within 24 hours of a concussion to the Rugby Football League in elite senior and academy levels. All data used in this study was extracted from this dataset spanning the seasons 2016 to 2022.  The data was extracted from the top tier Super League (n = 12 teams), second tier Championship (n = 14 teams), and RFL Academy (n = 12 teams). A total of 1403 concussions were reported (Super League = 538; Championship = 358; Academy = 507). The overall concussion incidence was significantly higher for Super League (15.5 (14.2–16.9) per 1000 player-match hours) and Academy (14.3 (13.1-15.6) per 1000 player-match hours) compared to the Championship (10.5 (9.5-11.7) per 1000 player match hours). One possible reason for this difference is the increased availability of resources for identifying concussions. Additionally, there has been an emphasis on concussion caution for youth players. Concussion incidence in Academy players was higher in the 2021 and 2022 seasons, potentially influenced by COVID-19 pandemic, which limited training and playing opportunities for these players. Lastly, no difference was found in concussion incidence between months at all the levels.

This study is published in the Journal of Science and Medicine in Sport.

Eastwood, David et al. Incidence of concussion in men’s Super League, Championship, and Academy rugby league matches between 2016 and 2022. Journal of Science and Medicine in Sport, 2023. doi: https://doi.org/10.1016/j.jsams.2023.09.001

It Takes Two to Tango: High Rates of Injury and Concussion in Ball Carriers and Tacklers in High School Boys’ Rugby

The purpose of this study is to explore injuries in Canadian high school rugby boys and provide insights for future injury prevention strategies. Data collection took place during the 2018 and 2019 high-school rugby seasons in Calgary, Alberta. Seven schools were recruited for this study and 12 teams were included.  Preseason testing was conducted at the start of the season, with weekly visits to the schools during the season to obtain the injury data. The total time loss injury incidence for matches was 48.4 injury per 1000 hours (95% CI: 37.7-62.0) and a concussion injury incidence of 22.0 concussions per 1000 hours (95% CI: 15.9-30.4). For training injury incidence, the overall time-loss injury incidence was 1.9 injuries per 1000 hours (95% CI: 1.2- 2.9) and the training concussion injury incidence was 0.6 injuries per 1000 hours (95% CI: 0.3-1.2). No significant differences were observed between seasons. The head was the most common injury location in both matches and training, with the concussion being the most common injury type. The tackle event accounted for 65% of match injuries, with the ball carrier contributing to 35% of tackle injuries, followed by the tackler (30%). In training, the tackle constituted 58% of injuries, with the tackler having the highest injury proportion (51%) compared to the ball carrier (7%). The most common mechanism for concussions in matches was being tackled (41%), followed by tackling (53%). In training, the predominant concussion mechanism was tackling (45%), followed by being tackled (23%). The authors highlighted the need for implementation of injury and concussion-specific prevention strategies. Due to the significant number of tackle-related injuries, there is a need to focus on tackle specific injury prevention strategies.

This study is published in the Clinical Journal of Sport Medicine.

West, Stephen W., Shill, Isla J., Sick, Stacy., et al. It Takes Two to Tango: High Rates of Injury and Concussion in Ball Carriers and Tacklers in High School Boys’ Rugby. Clinical Journal of Sport Medicine 33(4):p 405-413, July 2023. doi: 10.1097/JSM.0000000000001118

Rugby Science Update 11

I won’t let you down; why 20% of Men’s and Women’s Super League players underreported suspected concussions

The purpose of this study was to determine the rates of concussion underreporting in male and female Super League rugby players and to establish why players may not report suspected concussions. Furthermore, the study aimed to establish basic concussion knowledge and awareness of the long-term implications of concussions. This study undertook a cross sectional design. A survey was distributed to all registered men’s and women’s players from Super League teams by the Rugby Football League during the 2022 preseason. A total of 422 players completed the survey. Of the 422 players, 20% did not report concussion-related symptoms to the medical staff during the 2020 and 2021 seasons. One third of all players reported at least one concussion diagnosed by a doctor over the last two seasons. The most common reason for not reporting concussion-related symptoms were that players ‘didn’t want to be ruled out of a match’ and ‘didn’t want to let down team’. 62% of players reported receiving annual concussion education at their clubs. Knowledge about concussion and its potential long term implications improved from the beginning of the players senior club level careers. More than half of the players expressed concern about the potential long-term implications of concussions. The authors encourage medical and performance staff to be involved in concussion education to remove any negative perceptions surrounding concussion reporting.

This study is published in the Journal of Science and Medicine in Sport.

Tadmor D, Till K, Phillips G, Brown J, Fairbank L, Hendricks S, Johnston RD, Longworth T, Stokes K, Jones B. I won’t let you down; why 20% of Men’s and Women’s Super League players underreported suspected concussions. J Sci Med Sport. 2023 Sep 27:S1440-2440(23)00416-4. DOI: 10.1016/j.jsams.2023.09.015.

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

The aim of this study was two-fold:  to describe the tackle characteristics during a single season, of community-level rugby conducted under the lowered, armpit-level maximum legal tackle height law variation and investigate factors that were associated with ‘high tackles under the new law’, during this season. The tackle analysis was completed throughout the Koshuis rugby competition in Stellenbosch University rugby club’s intra-university competition in 2018 and 2019, comprising of four leagues with 42 teams. The first year of the study used the standard shoulder-level maximum tackle height law and in the second year of the study the maximum legal tackle height was lowered from the ball carrier’s shoulder to the armpit. All matches were video recorded with referees wore Go Pro camera, and injury surveillance was conducted. The tackles were categorised as ‘high tackle under the new law’ or ‘not high’. A total of 108 matches and 14679 tackles were analysed. The results showed that ‘high tackles under the new law’ had significantly greater odds of occurring in the lower leagues. Notably, factors contributing to high tackles under the law variation condition included, lower front-on arm tackler, tacklers in upright positions, and ball carriers dipping into contact, all of which were associated with an increased risk of head injury. In conclusion, these findings support the implementation of a lowered maximum legal tackle height in rugby union. The authors did mention that when lowering the maximum legal tackle height, the ball carrier’s behaviour in the tackle event needs to be considered.

This study is published in the Journal of Science and Medicine in Sport.

R. van Tonder, S. Hendricks, L. Starling, et al., 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, Journal of Science and Medicine in Sport (2023), https://doi.org/10.1016/j.jsams.2023.10.011

Coach and player rating of perceived challenge (RPC) as a skill monitoring tool in Rugby Union

The aim of this study was to determine the relationship between player and coach Rating of Perceived Challenge (RPC) for different training sessions over a competitive rugby union season and explore the relationship between player RPC and Rating of Perceived Exertion (RPE). This observational study monitored 51 highly trained U21 rugby union players and four coaches over an 11-week competitive rugby season. Throughout the season players were asked for their RPC and RPE ratings 15 to 30 minutes after each team session, split session, and gym session, while the coaches were asked to provide their RPC ratings based on observation. All ratings were collected independently and confidentially. The key finding in this study was that, overall, players’ RPC did not match the coaches RPC, suggesting that the rugby union coaches may be overestimating the technical and tactical challenge of their training sessions. Additionally, forwards had a higher RPC for field sessions, likely due to their additional technical and tactical demands from training scrums, lineouts, and mauls. The authors mentioned that further robust validity studies are needed.

This study is published in the International Journal of Sports Science and Coaching.

Bam, J., Watson, N., Parker, N., Lambert, M., Jones, B., Weston, M., & Hendricks, S. (2023). Coach and player rating of perceived challenge (RPC) as a skill monitoring tool in Rugby union. International Journal of Sports Science & Coaching, 18(4), 1010-1017. https://doi.org/10.1177/17479541231166287

Rugby Science Update 10

Predicting performance at the group-phase and knockout-phase of the 2015 Rugby World Cup

The objective of this study was to develop a predictive model for performance during the group-phase of the 2015 Rugby World Cup (RWC) and to determine the most significant and relevant performance indicators for predicting match outcome. Performance indicators were downloaded from the OPTA website from the 2015 RWC (40 group-phase and 8 knockout-phase matches) to be analysed. A random forest classification model was developed to establish the relationship between the performance indicators and the match outcomes. The model created using the group-phase matches achieved a 100% accuracy of predicting match outcomes. When applied to the knockout-phase matches, this model had an overall accuracy of 87.5%, with sensitivity and specificity of 87.5%. The model identified 13 performance indicators that significantly predicted match outcomes. These included tackle-ratio, clean breaks, average carry, lineouts won, penalties conceded, missed tackles, lineouts won in the opposition 22, defenders beaten, metres carried, kicks from hand, lineout success, penalties in opposition 22 m and scrums won. The performance indicators in the group-phase matches that could predict the match outcomes were tackle ratio, clean breaks and average carry. Interestingly, the performance indicators do not change from the group to knockout stages. The findings of this study provide insights for rugby teams to assess their performance and understand the major technical factors contributing to success and failure in individual matches. Coaches and sport practitioners can then adjust their technical and tactical training appropriately.

This study is published in European Journal of Sport Science.

Mark Bennett, Neil E. Bezodis, David A. Shearer & Liam P. Kilduff (2021) Predicting performance at the group-phase and knockout-phase of the 2015 Rugby World Cup, European Journal of Sport Science, 21:3, 312-320, DOI: 10.1080/17461391.2020.1743764

Statistical Review and Match Analysis of Rugby World Cups Finals

The purpose of this study was to describe game statistics and match analysis of Rugby World Cups from 1987 to 2015. The analysis focused on all final matches (n = 8) from 1987 to 2015 Rugby World Cups, and official reports from the Rugby World Cup webpages were also included in the analysis.  This analysis included tracking counts of all match activities. 39 key performance indicators were categorised into seven groups: mode of scoring, set-pieces, defensive, offensive, infringements, replacements, and team/time possession efficiency. It was observed that the winning teams of the final matches in the Rugby World Cup attempted more penalty kicks. Interesting, the number of drop goals were similar between the winning and losing teams.  The winning teams won more set pieces, including winning scrums and lineouts. In the defensive category, the winning teams attempted and completed more tackles than the losing teams. Regarding, the offensive category, the winning teams passed less, completed fewer offloads, and were involved in more rucks and mauls. Interestingly, it was noted that the losing teams made more substitutions than the winning teams. Furthermore, both teams in the Rugby World Cup finals shared similar possession of the ball.  The authors of the study mentioned the importance of player emotions, as well as conducting more in-depth match analysis to enhance team performance characteristics.

This study is published in Journal of Human Kinetics.

Vaz, Luís & Hendricks, Sharief & Kraak, Wilbur. (2019). Statistical Review and Match Analysis of Rugby World Cups Finals. Journal of Human Kinetics. 66. DOI: 10.2478/hukin-2018-0061.

How to harness and improve on video analysis for youth rugby player safety: a narrative review

The purpose of this narrative review is to synthesize the strengths and limitations of video analysis in youth rugby used for injury surveillance, highlight the importance of video analysis for youth player safety and discuss recommendations. This review highlights multiple strengths and limitations of video analysis in youth rugby for injury surveillance. It is recommended in this review that video assessment of injury and concussion outcomes be prioritised to educate, inform and improve youth rugby safety. The importance of analysing these outcomes is highlighted within this review which develops and guides targeted injury and concussion prevention strategies. Furthermore, a video analysis framework consensus that is specific to youth rugby is needed.

This study is published in BMJ Open Sport & Exercise Medicine.

Shill IJ, West SW, Brown J, Wilson F, Palmer D, Pike I, Hendricks S, Stokes KA, Hagel BE, Emery CA. How to harness and improve on video analysis for youth rugby player safety: a narrative review. BMJ Open Sport Exerc Med. 2023 Sep 27;9(3):e001645. DOI: 10.1136/bmjsem-2023-001645.