Head Acceleration Events During Tackle, Ball-Carry, and Ruck Events in Professional Southern Hemisphere Men's Rugby Union Matches: A Study Using Instrumented Mouthguards.

OBJECTIVES: Describe head acceleration events (HAEs) experienced by professional male rugby union players during tackle, ball-carry, and ruck events using instrumented mouthguards (iMGs). DESIGN: Prospective observational cohort. METHODS: Players competing in the 2023 Currie Cup (141 players) and Super Rugby (66 players) seasons wore iMGs. The iMG-recorded peak linear acceleration (PLA) and peak angular acceleration (PAA) were used as in vivo HAE approximations and linked to contact-event data captured using video analysis. Using the maximum PLA and PAA per contact event (HAEmax), ordinal mixed-effects regression models estimated the probabilities of HAEmax magnitude ranges occurring, while accounting for the multilevel data structure. RESULTS: As HAEmax magnitude increased the probability of occurrence decreased. The probability of a HAEmax ≥15g was 0.461 (0.435-0.488) (approximately 1 in every 2) and ≥45g was 0.031 (0.025-0.037) (1 in every 32) during ball carries. The probability of a HAEmax >15g was 0.381 (0.360-0.404) (1 in every 3) and >45g 0.019 (0.015-0.023) (1 in every 53) during tackles. The probability of higher magnitude HAEmax occurring was greatest during ball carries, followed by tackles, defensive rucks and attacking rucks, with some ruck types having similar profiles to tackles and ball carries. No clear differences between positions were observed. CONCLUSION: Higher magnitude HAEmax were relatively infrequent in professional men's rugby union players. Contact events appear different, but no differences were found between positions. The occurrence of HAEmax was associated with roles players performed within contact events, not their actual playing position. Defending rucks may warrant greater consideration in injury prevention research.

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.

Consensus on a netball video analysis framework of descriptors and definitions by the netball video analysis consensus group.

Using an expert consensus-based approach, a netball video analysis consensus (NVAC) group of researchers and practitioners was formed to develop a video analysis framework of descriptors and definitions of physical, technical and contextual aspects for netball research. The framework aims to improve the consistency of language used within netball investigations. It also aims to guide injury mechanism reporting and identification of injury risk factors. The development of the framework involved a systematic review of the literature and a Delphi process. In conjunction with commercially used descriptors and definitions, 19 studies were used to create the initial framework of key descriptors and definitions in netball. In a two round Delphi method consensus, each expert rated their level of agreement with each of the descriptors and associated definition on a 5-point Likert scale (1-strongly disagree; 2-somewhat disagree; 3-neither agree nor disagree; 4-somewhat agree; 5-strongly agree). The median (IQR) rating of agreement was 5.0 (0.0), 5.0 (0.0) and 5.0 (0.0) for physical, technical and contextual aspects, respectively. The NVAC group recommends usage of the framework when conducting video analysis research in netball. The use of descriptors and definitions will be determined by the nature of the work and can be combined to incorporate further movements and actions used in netball. The framework can be linked with additional data, such as injury surveillance and microtechnology data.

The speed and acceleration of the ball carrier and tackler into contact during front-on tackles in rugby league.

The aim was to use a combination of video analysis and microtechnology (10 Hz global positioning system [GPS]) to quantify and compare the speed and acceleration of ball-carriers and tacklers during the pre-contact phase (contact - 0.5s) of the tackle event during rugby league match-play. Data were collected from 44 professional male rugby league players from two Super League clubs across two competitive matches. Tackle events were coded and subject to three stages of inclusion criteria to identify front-on tackles. 10 Hz GPS data was synchronised with video to extract the speed and acceleration of the ball-carrier and tackler into each front-on tackle (n = 214). Linear mixed effects models (effect size [ES], confidence intervals, p-values) compared differences. Overall, ball-carriers (4.73 ± 1.12 m∙s-1) had greater speed into front-on tackles than tacklers (2.82 ± 1.07 m∙s-1; ES = 1.69). Ball-carriers accelerated (0.67 ± 1.01 m∙s-2) into contact whilst tacklers decelerated (-1.26 ± 1.36 m∙s-2; ES = 1.74). Positional comparisons showed speed was greater during back vs. back (ES = 0.66) and back vs. forward (ES = 0.40) than forward vs. forward tackle events. Findings can be used to inform strategies to improve performance and player welfare.

A novel application of entropy analysis for assessing changes in movement variability during cumulative tackles in young elite rugby league players.

The aim of this study was to identify between-position (forwards vs. backs) differences in movement variability in cumulative tackle events training during both attacking and defensive roles. Eleven elite adolescent male rugby league players volunteered to participate in this study (mean ± SD, age; 18.5 ± 0.5 years, height; 179.5 ± 5.0 cm, body mass; 88.3 ± 13.0 kg). Participants performed a drill encompassing four blocks of six tackling (i.e. tackling an opponent) and six tackled (i.e. being tackled by an opponent while carrying a ball) events (i.e. 48 total tackles) while wearing a micro-technological inertial measurement unit (WIMU, Realtrack Systems, Spain). The acceleration data were used to calculate sample entropy (SampEn) to analyse the movement variability during tackles performance. In tackling actions SampEn showed significant between-position differences in block 1 (p = 0.0001) and block 2 (p = 0.0003). Significant between-block differences were observed in backs (block 1 vs 3, p = 0,0021; and block 1 vs 4, p = 0,0001) but not in forwards. When being tackled, SampEn showed significant between-position differences in block 1 (p = 0.0007) and block 3 (p = 0.0118). Significant between-block differences were only observed for backs in block 1 vs 4 (p = 0,0025). Movement variability shows a progressive reduction with cumulative tackle events, especially in backs and when in the defensive role (tackling). Forwards present lower movement variability values in all blocks, particularly in the first block, both in the attacking and defensive role. Entropy measures can be used by practitioners as an alternative tool to analyse the temporal structure of variability of tackle actions and quantify the load of these actions according to playing position.

Ready for impact? A validity and feasibility study of instrumented mouthguards (iMGs).

OBJECTIVES: Assess the validity and feasibility of current instrumented mouthguards (iMGs) and associated systems. METHODS: Phase I; four iMG systems (Biocore-Football Research Inc (FRI), HitIQ, ORB, Prevent) were compared against dummy headform laboratory criterion standards (25, 50, 75, 100 g). Phase II; four iMG systems were evaluated for on-field validity of iMG-triggered events against video-verification to determine true-positives, false-positives and false-negatives (20±9 player matches per iMG). Phase III; four iMG systems were evaluated by 18 rugby players, for perceptions of fit, comfort and function. Phase IV; three iMG systems (Biocore-FRI, HitIQ, Prevent) were evaluated for practical feasibility (System Usability Scale (SUS)) by four practitioners. RESULTS: Phase I; total concordance correlation coefficients were 0.986, 0.965, 0.525 and 0.984 for Biocore-FRI, HitIQ, ORB and Prevent. Phase II; different on-field kinematics were observed between iMGs. Positive predictive values were 0.98, 0.90, 0.53 and 0.94 for Biocore-FRI, HitIQ, ORB and Prevent. Sensitivity values were 0.51, 0.40, 0.71 and 0.75 for Biocore-FRI, HitIQ, ORB and Prevent. Phase III; player perceptions of fit, comfort and function were 77%, 6/10, 55% for Biocore-FRI, 88%, 8/10, 61% for HitIQ, 65%, 5/10, 43% for ORB and 85%, 8/10, 67% for Prevent. Phase IV; SUS (preparation-management) was 51.3-50.6/100, 71.3-78.8/100 and 83.8-80.0/100 for Biocore-FRI, HitIQ and Prevent. CONCLUSION: This study shows differences between current iMG systems exist. Sporting organisations can use these findings when evaluating which iMG system is most appropriate to monitor head acceleration events in athletes, supporting player welfare initiatives related to concussion and head acceleration exposure.

Physical and Technical Demands and Preparatory Strategies in Female Field Collision Sports: A Scoping Review.

Women's participation in field collision sports is growing worldwide. Scoping reviews provide an overview of scientific literature in a developing area to support practitioners, policy, and research priorities. Our aim is to explore published research and synthesise information on the physical and technical demands and preparation strategies of female field collision sports. We searched four databases and identified relevant published studies. Data were extracted to form (1) a numerical analysis and (2) thematic summary. Of 2318 records identified, 43 studies met the inclusion criteria. Physical demands were the most highly investigated (n+=+24), followed by technical demands (n+= 18), tactical considerations (n+=+8) and preparatory strategies (n=1). The key themes embody a holistic model contributing to both performance and injury prevention outcomes in the context of female field collision sports. Findings suggest a gender data gap across all themes and a low evidence base to inform those preparing female athletes for match demands. Given the physical and technical differences in match-demands the review findings do not support the generalisation of male-derived training data to female athletes. To support key stakeholders working within female field collision sports there is a need to increase the visibility of female athletes in the literature.

Are rugby league players involved in more tackles than normal, prior to an injury sustained during a tackle event?

Rugby league has a relatively high injury risk, with the tackle having the greatest injury propensity. The number of tackles players engage in, prior to injurious tackles may influence injury risk, which has yet to be investigated. Therefore, this study investigated if rugby league players are involved in more tackles (as either tackler or ball carrier) (i) in the 10 minutes, or (ii) 1-min periods prior to an injurious tackle-event, (iii) differences for ball carriers vs. tacklers, and (iv) forwards vs. backs. Video analysis was utilised to quantify the number and rate of tackles in the 10-min periods prior to 61 tackle-related injuries. One thousand two hundred and eighty 10-min periods where players were not injured, were used as matched-controls. Generalized mixed linear models were used to analyse mean total and rate for tackles. Injured players were involved in significantly fewer tackles during the 10-min period, yet significantly more tackles during the final minute prior to the injurious tackle-event, compared to non-injured players. There were no differences between ball carriers vs. tacklers during the 10-min period. Both injured position groups were involved in significantly more tackles in the final minute. Additional match data sources are needed to further inform injury preventive strategies of tackle events.

Inside edge - prevalence and factors associated with symptoms of anxiety/depression in professional cricketers.

The purpose of this study was to i) determine the prevalence of anxiety/depression symptoms in professional cricketers and ii) identify factors associated with symptoms of anxiety/depression. One-hundred and seventy-seven (n = 177, response rate of 76%) professional cricketers completed the General Health Questionnaire 12 (GHQ-12). Odd ratios (OR) for anxiety/depression symptoms were related to players' career, family and education. Prevalence of symptoms of anxiety/depression was 59% (n = 104/177). Anxiety/depression symptoms increased when players were contracted for more than 2 years (OR: 5.0; 95% CI: 1.2-21.3; p = 0.028) and if they played their last offseason overseas (OR: 3.5; 95% CI: 1.3-9.6; p = 0.013). Anxiety/depression symptoms decreased by 70% when players made "productive use" of their time in the offseason (OR: 0.3; 95% CI: 0.1-0.9; p = 0.036) and contracted for 2 years (OR: 0.3; 95% CI: 0.1-1.0; p = 0.049). These findings can be incorporated into cricket mental health literacy programmes to improve awareness and understanding, and to encourage early help-seeking.

Tackle Technique and Changes in Playerload™ During a Simulated Tackle: An Exploratory Study.

In collision sports, the tackle has the highest injury incidence, and is key to a successful performance. Although the contact load of players has been measured using microtechnology, this has not been related to tackle technique. The aim of this study was to explore how PlayerLoad™ changes between different levels of tackling technique during a simulated tackle. Nineteen rugby union players performed twelve tackles on a tackle contact simulator (n = 228 tackles). Each tackle was recorded with a video-camera and each player wore a Catapult OptimEyeS5. Tackles were analysed using tackler proficiency criteria and split into three categories: Low scoring(≤5 Arbitrary units (AU), medium scoring(6 and 7AU) and high scoring tackles(≥8AU). High scoring tackles recorded a higher PlayerLoad™ at tackle completion. The PlayerLoad™ trace was also less variable in the high scoring tackles. The variability in the PlayerLoad™ trace may be a consequence of players not shortening their steps before contact. This reduced their ability to control their movement during the contact and post-contact phase of the tackle and increased the variability. Using the PlayerLoad™ trace in conjunction with subjective technique assessments offers coaches and practitioners insight into the physical-technical relationship of each tackle to optimise tackle skill training and match preparation.

BokSmart rugby safety education courses are associated with improvements in behavioural determinants in attending coaches and referees: presurvey-postsurvey study.

BACKGROUND/AIM: BokSmart is a nationwide injury prevention programme that aims to reduce players' injury risk mainly through education of coaches and referees in mandatory biennial education courses. These courses are held throughout each rugby season. The objective of this cross-sectional study was to assess whether these courses were associated with improvements in attendees' behavioural determinants. METHODS: Coaches and referees completed a questionnaire based on the theory of planned behaviour, immediately before and after their 2012 BokSmart courses. Twelve behavioural determinants were assessed on a five-point Likert scale and open-ended questions. A meaningful change was defined as an improvement of ≥1 unit score supported by null hypothesis testing. Odds of improving by ≥1 unit score (compared with not improving) were assessed in attendees using multivariate logistic regression. RESULTS: In total, 390 coaches and 74 referees completed both questionnaires. 'Before' scores were high for most outcomes, except for knowledge. Although there was a significant (p<0.001) improvement in all 'after' course scores, the only meaningful change (=1 unit) was in knowledge of scrum techniques/rules. CONCLUSION: Although the only meaningful improvement in 2012 BokSmart course attendees was in one outcome, it should be noted that before-course scores were already high, reducing the questionnaire's ability to assess change because of a ceiling effect. Nonetheless, the knowledge acquisition of these courses was low and not related to previous course attendance or more years of rugby experience. These results justify the biennial nature of this safety course but also indicate that knowledge acquisition is generally low.

The Use of Twitter by Medical Journals: Systematic Review of the Literature.

BACKGROUND: Medical journals use Twitter to engage and disseminate their research articles and implement a range of strategies to maximize reach and impact. OBJECTIVE: This study aims to systematically review the literature to synthesize and describe the different Twitter strategies used by medical journals and their effectiveness on journal impact and readership metrics. METHODS: A systematic search of the literature before February 2020 in four electronic databases (PubMed, Web of Science, Scopus, and ScienceDirect) was conducted. Articles were reviewed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. RESULTS: The search identified 44 original research studies that evaluated Twitter strategies implemented by medical journals and analyzed the relationship between Twitter metrics and alternative and citation-based metrics. The key findings suggest that promoting publications on Twitter improves citation-based and alternative metrics for academic medical journals. Moreover, implementing different Twitter strategies maximizes the amount of attention that publications and journals receive. The four key Twitter strategies implemented by many medical journals are tweeting the title and link of the article, infographics, podcasts, and hosting monthly internet-based journal clubs. Each strategy was successful in promoting the publications. However, different metrics were used to measure success. CONCLUSIONS: Four key Twitter strategies are implemented by medical journals: tweeting the title and link of the article, infographics, podcasts, and hosting monthly internet-based journal clubs. In this review, each strategy was successful in promoting publications but used different metrics to measure success. Thus, it is difficult to conclude which strategy is most effective. In addition, the four strategies have different costs and effects on dissemination and readership. We recommend that journals and researchers incorporate a combination of Twitter strategies to maximize research impact and capture audiences with a variety of learning methods.

Tackler and ball-carrier technique during moderate and severe injuries (≥8 days lost) compared with player-matched and team-matched injury-free controls in Elite Rugby Union.

OBJECTIVE: To analyse tackler and ball-carrier technical proficiency during moderate and severe contact injuries (≥8 days lost) in professional rugby union, and compare it with injury-free event-matched controls from the same player and from the same team. METHODS: Technical proficiency for 74 (n=74) (moderate and severe; ≥8 days lost) tackler and ball-carrier injuries during The Currie Cup (2014-2018) and 623 matched non-injury events (253 own controls, 370 team controls) were examined through video analysis using a standardised list of technical criteria. RESULTS: Mean technical proficiency score for injured tacklers during front-on tackles was 6.19/16 (arbitrary units (AU) 95% CI 4.89 to 7.48), which was significantly different to their own controls (8.90/16 AU, 95% CI 8.37 to 9.43, p<0.001, effect size (ES)=1.21, large) and team controls (9.93/16 AU, 95% CI 9.50 to 10.40, p<0.001, ES=1.71, large). Mean technical proficiency score for injured ball-carriers during front-on tackles was 5.60/14 AU (95% CI 4.65 to 6.55), which was significantly different to their own controls (8.08/14 AU, 95% CI 7.56 to 8.60, p<0.001, ES=1.16, moderate) and team controls (8.16/14 AU, 95% CI 7.75 to 8.57, p<0.001, ES=1.25, large). CONCLUSION: For the tackler and ball-carrier, for both front-on and side-on/behind tackles, overall technical proficiency scores were significantly lower for the injury-causing event, when compared with the player's own injury-free tackles and the team's injury-free tackles. Through analysing player and team controls, player technique deficiencies for the injured player and player technique deficiencies that expose all players to injury were highlighted, which may inform injury prevention strategies and policies, and assist coaches in optimising training to reduce tackle injury risk.

Consensus on a video analysis framework of descriptors and definitions by the Rugby Union Video Analysis Consensus group.

Using an expert consensus-based approach, a rugby union Video Analysis Consensus (RUVAC) group was formed to develop a framework for video analysis research in rugby union. The aim of the framework is to improve the consistency of video analysis work in rugby union and help enhance the overall quality of future research in the sport. To reach consensus, a systematic review and Delphi method study design was used. After a systematic search of the literature, 17 articles were used to develop the final framework that described and defined key actions and events in rugby union (rugby). Thereafter, a group of researchers and practitioners with experience and expertise in rugby video analysis formed the RUVAC group. Each member of the group examined the framework of descriptors and definitions and rated their level of agreement on a 5-point agreement Likert scale (1: strongly disagree; 2: disagree; 3: neither agree or disagree; 4: agree; 5: strongly agree). The mean rating of agreement on the five-point scale (1: strongly disagree; 5: strongly agree) was 4.6 (4.3-4.9), 4.6 (4.4-4.9), 4.7 (4.5-4.9), 4.8 (4.6-5.0) and 4.8 (4.6-5.0) for the tackle, ruck, scrum, line-out and maul, respectively. The RUVAC group recommends using this consensus as the starting framework when conducting rugby video analysis research. Which variables to use (if not all) depends on the objectives of the study. Furthermore, the intention of this consensus is to help integrate video data with other data (eg, injury surveillance).

Assessing tackle performance using a novel collision sport simulator in comparison to a "live" one-on-one tackling drill.

It is necessary to study the rugby tackle as it is associated with successful performance outcomes and is responsible for the majority of contact injuries. A novel collision sport simulator was developed to study tackle performance. The main aim of this validation study was to assess tackle technique performance between two different conditions: simulator versus a standardised one-on-one tackle drill previously used to assess technique. Tackling proficiency was assessed using a list of technical criteria. Mean scores, standard deviations and Cohen's d effect sizes were calculated. Mean overall score for dynamic i.e. running simulator tackles was 7.78 (95%CI 7.58-7.99) (out of 9) or 87% (standard deviation or SD±8.94), and mean overall score for dynamic "live" tackles was 7.85 (95%CI 7.57-8.13) (out of 9) or 87% (SD±9.60) (effect size = 0.08; trivial; p > 0.05). Mean overall score for static i.e. standing simulator tackles was 7.45 (95%CI 7.20-7.69) (out of 9) or 83% (SD±10.71), and mean overall score for static "live" tackles was 8.05 (95%CI 7.83-8.27) (out of 9) or 89% (SD±7.53) (effect size = 0.72; moderate; p < 0.001). The simulator replicates dynamic tackle technique comparable to real-life tackle drills. It may be used for research analysing various aspects of the tackle in rugby and other contact sports.

Tackle and ruck technique proficiency within academy and senior club rugby union.

This study examined the validity of a tool that assesses tackle and ruck technique in training and established reference data for tackle, ball-carry and ruck technique at different levels of play in rugby union. One hundred and thirty-one amateur rugby union players; 37 senior, 51 first-grade academy and 43 second-grade academy players, participated in a two-on-two contact drill. The drill was filmed and the players' tackle, ball-carry and ruck technique were assessed using standardized technical criteria. Senior level players scored significantly higher in all three assessments; tackle technique senior vs academy 1st (p < 0.01, effect size (ES) = 0.7, moderate), senior vs academy 2nd (p < 0.01, ES = 0.7, moderate); ball-carry technique senior vs academy 1st (p < 0.01, ES = 0.6, moderate), senior vs academy 2nd (p < 0.01, ES = 0.8, moderate); ruck technique senior vs academy 1st (p < 0.01, ES = 0.7, moderate), senior vs academy 2nd (p < 0.01, ES = 0.4, small). These findings emphasize the importance of developing contact technique to allow players to progress to higher levels, and provide validity to an assessment tool which can facilitate this process.