Knowledge-guided analysis of "omics" data using the KnowEnG cloud platform.

We present Knowledge Engine for Genomics (KnowEnG), a free-to-use computational system for analysis of genomics data sets, designed to accelerate biomedical discovery. It includes tools for popular bioinformatics tasks such as gene prioritization, sample clustering, gene set analysis, and expression signature analysis. The system specializes in "knowledge-guided" data mining and machine learning algorithms, in which user-provided data are analyzed in light of prior information about genes, aggregated from numerous knowledge bases and encoded in a massive "Knowledge Network." KnowEnG adheres to "FAIR" principles (findable, accessible, interoperable, and reuseable): its tools are easily portable to diverse computing environments, run on the cloud for scalable and cost-effective execution, and are interoperable with other computing platforms. The analysis tools are made available through multiple access modes, including a web portal with specialized visualization modules. We demonstrate the KnowEnG system's potential value in democratization of advanced tools for the modern genomics era through several case studies that use its tools to recreate and expand upon the published analysis of cancer data sets.

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.

When This Happens, You Want the Best Care: Players' Experiences of Barriers and Facilitators of the Immediate Management of Rugby-Related Acute Spinal Cord Injury.

Most contact sports, including rugby union, carry a risk of injury. Although acute spinal cord injuries (ASCIs) in rugby are rare, the consequences of such injuries are far-reaching. Optimal management of these injuries is challenging, and a detailed understanding of the different barriers and facilitators to optimal care is needed. In this study, we aimed to describe the perception of players, regarding factors related to the optimal immediate management of a catastrophic injury in a developing country with socioeconomic and health care inequities. The most frequently reported barriers were transportation delays after injury and admission to appropriate medical facilities. Other barriers included inadequate equipment, the quality of first aid care, and barriers within the acute hospital setting. Barriers were more prevalent in rural and lower socioeconomic areas. These findings are relevant for all rugby stakeholders and may help shape education, awareness, and future policy around the immediate management of ASCIs.

Changes in body mass, stature and BMI in South African elite U18 Rugby players from different racial groups from 2002-2012.

The purpose of this study was to determine whether there are differences between racial groups for body mass, stature and body mass index (BMI) in South African elite U18 rugby players and whether there were significant changes in these measurements between 2002 and 2012. Self-reported body mass and stature were obtained from U18 players (n = 4007) who attended the national tournament during this period. BMI was calculated for each player.White players were 9.8 kg heavier than black players, who were 2.3 kg heavier than coloured players (P < 0.0001). The body mass of all groups increased from 2002 to 2012 (P < 0.0001). White players were 7.0 cm taller than black players who were 0.5 cm taller than coloured players (P < 0.0001). Players' stature measurements did not change significantly during the study period. The average BMI of white players was 0.9 kg·m-2 greater than black players who were on average 0.7 kg·m-2 greater than coloured players (P < 0.0001). The BMI of all groups changed similarly over the study period. The body mass, stature and BMI of elite under-18 rugby players in South Africa were significantly different between racial groups. This has implications for transforming the game to make it representative of the South African population.

Technical determinants of tackle and ruck performance in International rugby union.

The most frequently occurring contact events in rugby union are the tackle and ruck. The ability repeatedly to engage and win the tackle and ruck has been associated with team success. To win the tackle and ruck, players have to perform specific techniques. These techniques have not been studied at the highest level of rugby union. Therefore, the purpose of this study was to identify technical determinants of tackle and ruck performance at the highest level of rugby union. A total of 4479 tackle and 2914 ruck events were coded for the Six Nations and Championship competitions. Relative risk ratio (RR), the ratio of the probability of an outcome occurring when a characteristic was observed (versus the non-observed characteristic), was determined using multinomial logistic regression. Executing front-on tackles reduced the likelihood of offloads and tackle breaks in both competitions (Six Nations RR 3.0 Behind tackle, 95% confidence interval [95% CI]: 1.9-4.6, effect size [ES] = large, P < 0.001); Championship RR 2.9 Jersey tackle, 95% CI: 1.3-6.4, ES = moderate, P = 0.01). Fending during contact increased the chances of offloading and breaking the tackle in both competitions (Six Nations RR 4.5 Strong, 95% CI: 2.2-9.2, ES = large, P = P < 0.001; Championship RR 5.1 Moderate, 95% CI: 3.5-7.4, ES = large, P < 0.001). For the ruck, actively placing the ball increased the probability of maintaining possession (Six Nations RR 2.2, 95% CI: 1.1-4.3, ES = moderate, P = 0.03); Championship RR 4.0, 95% CI: 1.3-11.8, ES = large, P = 0.01). The techniques identified in this study should be incorporated and emphasised during training to prepare players for competition. Furthermore, these techniques need to be added to coaching manuals for the tackle and ruck.

Evaluation of the Effectiveness and Implementation of the BokSmart Safe Six Injury Prevention Programme: a study protocol.

BACKGROUND: The injury burden in rugby union ('rugby') is high. While exercise-based injury prevention programmes have successfully reduced injuries in other sports such as football, there is minimal research on this topic in rugby union. OBJECTIVE: To evaluate the effectiveness and implementation of an exercise-based intervention (BokSmart Safe Six) in junior rugby players that aims to reduce the injury risk profile and burden of injury. SETTING: 14-16-year-old junior rugby players in two geographically separated locations in South Africa over the 2017 rugby playing season. METHODS: A cluster-randomised controlled trial where the teams are allocated to groups that either (1) have a coach-delivered exercise intervention in their warm-up (BokSmart Safe Six) or (2) continue with their warm-up 'as usual' (control group). Injury risk profiles will be assessed through musculoskeletal screening on all players performed at the beginning, middle and end of the trial. Epidemiological measurements include injury surveillance at all matches and training sessions, and exposure to the various warm-up exercises (including BokSmart Safe Six exercises). Behavioural determinants of coaches will be assessed through standardised theory of planned behaviour questionnaires and focus groups before and after the intervention. OUTCOME MEASURES: Comparison in injury risk profiles and burden of injury between the intervention and control groups. Changes in the behavioural determinants of coaches. TRIAL REGISTRATION NUMBER: PACTR201608001730223. Pre-Results.

Managing player load in professional rugby union: a review of current knowledge and practices.

BACKGROUND: The loads to which professional rugby players are subjected has been identified as a concern by coaches, players and administrators. In November 2014, World Rugby commissioned an expert group to identify the physical demands and non-physical load issues associated with participation in professional rugby. OBJECTIVE: To describe the current state of knowledge about the loads encountered by professional rugby players and the implications for their physical and mental health. FINDINGS: The group defined 'load' as it relates to professional rugby players as the total stressors and demands applied to the players. In the 2013-2014 seasons, 40% of professional players appeared in 20 matches or more, and 5% of players appeared in 30 matches or more. Matches account for ∼5-11% of exposure to rugby-related activities (matches, team and individual training sessions) during professional competitions. The match injury rate is about 27 times higher than that in training. The working group surmised that players entering a new level of play, players with unresolved previous injuries, players who are relatively older and players who are subjected to rapid increases in load are probably at increased risk of injury. A mix of 'objective' and 'subjective' measures in conjunction with effective communication among team staff and between staff and players was held to be the best approach to monitoring and managing player loads. While comprehensive monitoring holds promise for individually addressing player loads, it brings with it ethical and legal responsibilities that rugby organisations need to address to ensure that players' personal information is adequately protected. CONCLUSIONS: Administrators, broadcasters, team owners, team staff and the players themselves have important roles in balancing the desire to have the 'best players' on the field with the ongoing health of players. In contrast, the coaching, fitness and medical staff exert significant control over the activities, duration and intensity of training sessions. If load is a major risk factor for injury, then managing training loads should be an important element in enabling players to perform in a fit state as often as possible.

Forced Retirement from Professional Rugby Union is Associated with Symptoms of Distress.

Rugby has a higher injury burden than other popular sports, such as football. Athletes who are forced to retire as a result of injury are associated with poor mental health. With its high injury burden, professional rugby players might be at risk of mental health conditions associated with injury-related forced retirement. This study aimed to compare mental health between former professional rugby players who were and weren't forced to retire. A questionnaire including the 4DSQ (distress), GHQ-12 (anxiety/depression), PROMIS short-form (sleep disturbance) and AUDIT-C (alcohol misuse) was completed by retired professional players from Ireland, France and South Africa. The questionnaire asked players whether or not they were forced to retire, as well as the reason for retirement. Players forced to retire were more than twice as likely to report symptoms of distress in comparison to those that retired voluntarily (odds ratio: 2.1, 95% confidence interval: 1.2-3.6, p<0.001). None of the other mental health measures (anxiety/depression, sleep disturbance or alcohol misuse) were associated with forced retirement. In conclusion, rugby players that were forced to retire may require support structures and longitudinal monitoring. Future studies should begin monitoring players during their careers to accurately assess the effect of retirement on mental health.

Symptoms Of Common Mental Disorders In Professional Rugby: An International Observational Descriptive Study.

The aim of the study was to determine the prevalence of symptoms of common mental disorders among professional rugby players across countries. A cross-sectional analysis of the baseline questionnaires from an ongoing prospective cohort study was conducted. Nine national players' associations and three rugby unions distributed questionnaires based on validated scales for assessing symptoms of common mental disorders. Among the whole study sample (N=990; overall response rate of 28%), prevalence (4-week) of symptoms of common mental disorders ranged from 15% for adverse alcohol use to 30% for anxiety/depression. These findings support the prevalence rates of symptoms of common mental disorders found in previous studies among professional (i. e., elite) athletes across other sports, and suggestions can be made that the prevalence of symptoms of anxiety/depression seems slightly higher in professional rugby than in other general/occupational populations. Awareness of the prevalence of symptoms of common mental disorders should be improved in international rugby, and an interdisciplinary approach including psychological attention should be fostered in the medical care of professional rugby players. Adequate supportive measures to enhance awareness and psychological resilience would lead not only to improved health and quality of life among rugby players but arguably to enhanced performance in rugby.

Osteoarthritis is associated with symptoms of common mental disorders among former elite athletes.

PURPOSE: The primary aim was to establish the association between osteoarthritis (OA) and the occurrence and comorbidity of symptoms of common mental disorders (CMD: distress, anxiety/depression, sleep disturbance, adverse alcohol use) in a group of former elite athletes (rugby, football, ice hockey, Gaelic sports and cricket). A secondary aim was to explore this association in the subgroups of sports. METHODS: Cross-sectional analysis was performed on the baseline questionnaires from five prospective cohort studies conducted between April 2014 and January 2016 in former elite athletes of rugby, football, ice hockey, Gaelic sports and cricket. The presence of OA (diagnosed by a medical professional) was examined with a single question, and symptoms of CMD were evaluated through multiple validated questionnaires (4DSQ, GHQ-12, PROMIS, AUDIT-C). RESULTS: There was a significant association between OA and symptoms of distress (OR 1.7, 95 % CI 1.2-2.6), sleep disturbance (OR 1.6, 95 % CI 1.1-2.3), adverse alcohol use (OR 1.8, 95 % CI 1.2-2.6) and a comorbidity of symptoms of CMD (OR 1.5, 95 % CI 1.0-2.1) in former elite athletes. CONCLUSION: OA might be a risk factor for developing symptoms of CMD in former elite athletes. The clinical relevance of this study is that an interdisciplinary approach to the clinical care and support of former elite athletes after their careers is advocated as the interaction between the physical and mental health issues occurring on the long term is complex. Monitoring OA among former elite athletes should be empowered while strategies to prevent symptoms worsening should be developed and implemented. The self-awareness, prevention and care of mental health problems that might occur after a professional sports career should also be addressed. LEVEL OF EVIDENCE: Level III.

Incidence and Factors Associated With Concussion Injuries at the 2011 to 2014 South African Rugby Union Youth Week Tournaments.

OBJECTIVE: To determine the concussion incidence and to identify factors associated with concussion in South African youth rugby union players. DESIGN: Prospective cohort study. SETTING: Injury surveillance was completed at the South African Rugby Union Youth Week tournaments (under-13, under-16, and under-18 age groups). PARTICIPANTS: South African youth rugby union players. A total of 7216 players participated in 531 matches between 2011 and 2014. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Concussion incidence was calculated per 1000 player-match-hours with 95% CIs. Poisson regression was used to calculate the incidence rate ratio (IRR) between factors (age, time period, playing position, and activity at the time of concussion) potentially associated with concussions. RESULTS: The concussion incidence was 6.8/1000 player-match-hours (95% CI, 5.5-8.1) across all age groups. Under-13s (IRR, 1.5; P = 0.09) and under-16s (IRR, 1.7; P = 0.03) had higher concussion incidence rates than the under-18 age group. The incidence was higher in the third (IRR, 2.1; P = 0.04) and fourth (IRR, 2.5; P = 0.01) quarters of matches compared with the first quarter. Sixty-two percent of concussions occurred in the tackle situation. The tackler had a 4-fold greater concussion rate (IRR, 4.3; P < 0.001) compared with the ball carrier. The hooker and loose forwards had higher incidence rates than several other player positions (P < 0.05). CONCLUSIONS: The reported concussion incidence falls within the broad range previously reported in youth rugby. The evidence highlighted in this study may contribute to targeted concussion prevention strategies and provide a baseline against which the effectiveness of future interventions can be measured.

Preseason Functional Movement Screen Component Tests Predict Severe Contact Injuries in Professional Rugby Union Players.

Tee, JC, Klingbiel, JFG, Collins, R, Lambert, MI, and Coopoo, Y. Preseason Functional Movement Screen component tests predict severe contact injuries in professional rugby union players. J Strength Cond Res 30(11): 3194-3203, 2016-Rugby union is a collision sport with a relatively high risk of injury. The ability of the Functional Movement Screen (FMS) or its component tests to predict the occurrence of severe (≥28 days) injuries in professional players was assessed. Ninety FMS test observations from 62 players across 4 different time periods were compared with severe injuries sustained during 6 months after FMS testing. Mean composite FMS scores were significantly lower in players who sustained severe injury (injured 13.2 ± 1.5 vs. noninjured 14.5 ± 1.4, Effect Size = 0.83, large) because of differences in in-line lunge (ILL) and active straight leg raise scores (ASLR). Receiver-operated characteristic curves and 2 × 2 contingency tables were used to determine that ASLR (cut-off 2/3) was the injury predictor with the greatest sensitivity (0.96, 95% confidence interval [CI] = 0.79-1.0). Adding the ILL in combination with ASLR (ILL + ASLR) improved the specificity of the injury prediction model (ASLR specificity = 0.29, 95% CI = 0.18-0.43 vs. ASLR + ILL specificity = 0.53, 95% CI = 0.39-0.66, p ≤ 0.05). Further analysis was performed to determine whether FMS tests could predict contact and noncontact injuries. The FMS composite score and various combinations of component tests (deep squat [DS] + ILL, ILL + ASLR, and DS + ILL + ASLR) were all significant predictors of contact injury. The FMS composite score also predicted noncontact injury, but no component test or combination thereof produced a similar result. These findings indicate that low scores on various FMS component tests are risk factors for injury in professional rugby players.

Melamine contamination in nutritional supplements--Is it an alarm bell for the general consumer, athletes, and 'Weekend Warriors'?

BACKGROUND: Nutritional supplements are used or experimented with by consumers, notably these are; competitive and recreational athletes of all ages, and 'weekend warriors'. As a consequence the supplement industry has grown to meet the increasing demand. A Global Industry Analysts Inc. report indicates that the herbal supplement market has not declined during the worldwide recession, but in fact exhibited steady growth over the period 2008 to 2009. It is anticipated that the market will reach US$93.15 billion by the year 2015. These supplements may contain adulterated substances that may potentially have harmful short - and long-term health consequences to the consumer. "Scrap Melamine" is such an example, which has been implicated in the kidney failure and death of several cats, dogs and pigs. In China in 2008, reports described very severe health effects in infants and young children. At the time over 294,000 infants were screened and diagnosed with urinary tract stones and sand-like calculi associated with melamine in milk products, of which 50,000 infants were hospitalised, and at least six associated deaths, recorded. The extent that melamine contamination occurs in nutritional supplements is not known. Therefore, the aim of this study was to determine whether commercially available nutritional and traditional supplement products contain melamine, even though they are not declared by the manufacturer on the product label. METHODS: A total of 138 nutritional supplements products were obtained from (i) direct purchases from shops, pharmacies and outlets, (ii) directly from consumers, and (iii) from suppliers, manufacturers and distributors. The products were laboratory analysed for melamine, using Tandem Liquid Chromatography Mass Spectrometry. RESULTS: Forty-seven % of all the products (n = 138) tested positive for melamine. Eight-two % of the South African produced products (n = 27) tested positive and 58 % of the products imported into South Africa (n = 50) tested positive. The median concentration estimate for melamine in the products tested were, 6.0 µg/g for the 138 supplements tested, 8.9 µg/g for South African produced products, and 6.9 µg/g for products imported into South Africa. CONCLUSION: The melamine (undeclared on product label) levels detected in the nutritional supplements products investigated were within the Tolerable Daily intake (TDI) limit guidelines of 200 µg/g as set by WHO and others. Melamine over exposure within the context of the nutritional supplements consumption in the products investigated should not be of concern to the consumer provided the recommended guidelines of daily product use are adhered to. Further investigation is warranted to determine, (i) the link of melamine as (part) substitute for the perceived total declared protein content on the product label, (ii) cyanuric and uric acid presence in the supplement products that could form chemical-complex formation with melamine and/or analogues that could cause adverse health effects.

An evidence-driven approach to scrum law modifications in amateur rugby played in South Africa.

BACKGROUND: In 2012, the South African Rugby Union (SARU) approved a new set of scrum laws for amateur rugby played in the country, to be implemented at the start of the 2013 rugby season. These law changes were primarily based on the relatively high proportion of scrum-related catastrophic injury data collected as part of the BokSmart National Rugby Safety Programme (BokSmart) over the preceding 4 years (2008-2011). AIM: To describe the scrum-related catastrophic injury data in South Africa over the past 5 years (2008-2012), and to discuss how this evidence justifies the change in the Amateur Scrum Laws to make this aspect of the game safer in South Africa. METHODS: Catastrophic injury data were collected through BokSmart at amateur and professional levels, during training and matches over 5 years (2008-2012). RESULTS: The scrum phase accounted for 33% (n=20 of 60) of all catastrophic injuries between 2008 and 2012. Eighteen of the 20 scrum injuries (90%) were confirmed as acute spinal cord injuries, with 13 of these being permanent injuries. For the scrum injury mechanisms that were provided (n=19), 'impact on the engagement' was the most frequently reported (n=11 of 19, 58%), followed by 'collapsed scrum' (n=7 of 19, 37%) and 'popping out' (n=1 of 19, 5%). CONCLUSIONS: Based on these scrum-related catastrophic injury data, a change in the Amateur Scrum Laws of South African Rugby was justified. The main purpose of these scrum law changes is to reduce the number of scrum-related catastrophic injuries in the country, by minimising the opportunity for impact injury and subsequent scrum collapse in amateur rugby in South Africa, thereby making this aspect of the game of rugby safer.

Momentum and kinetic energy before the tackle in rugby union.

Understanding the physical demands of a tackle in match situations is important for safe and effective training, developing equipment and research. Physical components such as momentum and kinetic energy, and it relationship to tackle outcome is not known. The aim of this study was to compare momenta between ball-carrier and tackler, level of play (elite, university and junior) and position (forwards vs. backs), and describe the relationship between ball-carrier and tackler mass, velocity and momentum and the tackle outcome. Also, report on the ball-carrier and tackler kinetic energy before contact and the estimated magnitude of impact (energy distributed between ball-carrier and tackler upon contact). Velocity over 0.5 seconds before contact was determined using a 2-dimensional scaled version of the field generated from a computer alogorithm. Body masses of players were obtained from their player profiles. Momentum and kinetic energy were subsequently calculated for 60 tackle events. Ball-carriers were heavier than the tacklers (ball-carrier 100 ± 14 kg vs. tackler 93 ± 11 kg, d = 0.52, p = 0.0041, n = 60). Ball-carriers as forwards had a significantly higher momentum than backs (forwards 563 ± 226 Kg(.)m(.)s(-1) n = 31 vs. backs 438 ± 135 Kg(.)m(.)s(-1), d = 0.63, p = 0.0012, n = 29). Tacklers dominated 57% of tackles and ball-carriers dominated 43% of tackles. Despite the ball-carrier having a mass advantage before contact more frequently than the tackler, momentum advantage and tackle dominance between the ball-carrier and tackler was proportionally similar. These findings may reflect a characteristic of the modern game of rugby where efficiently heavier players (particularly forwards) are tactically predetermined to carry the ball in contact. Key PointsFirst study to quantify momentum, kinetic energy, and magnitude of impact in rugby tackles across different levels in matches without a device attached to a player.Physical components alone, of either ball-carrier or tackler, are not good predictors of tackle dominance.The range of magnitudes of impact of injury free tackles observed in this study provides evidence for the physical tolerance of players during the tackle.

Nutritional supplement products: Does the label information influence purchasing decisions for the physically active?

BACKGROUND: The increase in sales of nutritional supplement globally can be attributed, in part, to aggressive marketing by manufacturers, rather than because the nutritional supplements have become more effective. Furthermore, the accuracy of the labelling often goes unchallenged. Therefore, any effects of the supplement, may be due to contaminants or adulterants in these products not reflected on the label. METHODS: A self-administered questionnaire was used to determine how consumers of nutritional supplements acquired information to assist their decision-making processes, when purchasing a product. The study was approved by the University of Cape Town, Faculty of Health Sciences Human Research Ethics Committee. The questionnaire consisted of seven, closed and open-ended questions. The participants were asked to respond to the questions according to a defined list of statements. A total of 259 participants completed and returned questionnaires. The data and processing of the returned questionnaires was captured using Windows-based Microsoft® Office Excel 2003 SP 1 (Excel © 1985-2003 Microsoft Corporation). Statistica Version 10 (copyright © Stat Soft, Inc. 1984-2011) was used to calculate the descriptive statistics. RESULTS: The main finding of the study was that nearly 70% of the respondents who purchased supplements were strongly influenced by container label information that stipulated that the nutritional supplement product is free of banned substances. The second finding was that just over 50% of the respondents attached importance to the quality of the nutritional supplement product information on the container label. The third finding was that about 40% of the respondents were strongly influenced by the ingredients on the labels when they purchased nutritional supplements. CONCLUSION: This study, (i) identifies short-comings in current labelling information practices, (ii) provides opportunities to improve label and non-label information and communication, and, (iii) presents the case for quality assurance laboratory "screening testing" of declared and undeclared contaminants and/or adulterants, that could have negative consequences to the consumer.

Video-based technical feedback and instruction improves tackling technique of community rugby union players.

The aims of this study were to test the change and retention of player's overall tackling technique and technical components following a player-specific video-based technical feedback and instruction intervention on both their dominant and non-dominant shoulders. Twenty-four (n = 24) rugby union players participated in a non-randomized control-intervention, which consisted of a video-based technical feedback and instruction group (video-based technical feedback) and a no video-based technical feedback and instruction group (control). During 3 sessions (baseline, intervention, retention) separated by one week, participants in each group performed six tackles (3 tackles on each shoulder) on a tackle simulator. In total, 432 tackles (video-based technical feedback = 216, control = 216) were analysed. Each tackle was analysed using a standardized list of technical criteria (arbitrary units, AU). For the dominant shoulder, tackling technique scores significantly improved from baseline to intervention for both groups. For the non-dominant shoulder, only the video-based technical feedback group improved their tackling technique from baseline to intervention (baseline 6.89 [6.33-7.45] AU vs. intervention 7.72 [7.35-8.10] AU p = .001, ES = 0.60 moderate). For the retention session, the video-based technical feedback group scored significantly higher than the control group, for dominant (video-based technical feedback 8.00 [7.60-8.40] AU vs. control 7.22 [6.83-7.62] AU p = .014, ES = 0.66 moderate) and non-dominant (video-based technical feedback 8.11 [7.81-8.41] AU vs. control 7.22 [6.90-7.55] p = .004, ES = 0.96 moderate) tackles. This study demonstrates the efficacy of video-based technical feedback as a method to optimize tackle training for player safety and performance.HIGHLIGHTSVideo-based technical feedback can improve tackling technique in both dominant and non-dominant shoulders.Video-based technical feedback group continued to improve following a retention interval of one week.The video-based technical feedback group showed a significant (with a moderate effect size) improvement from baseline for two techniques - namely, "body position - upright to low" and "drive through contact with legs and shoulders".Video-based technical feedback can be used as a method to optimize tackle training for injury prevention and performance.

A global perspective on collision and non-collision match characteristics in male rugby union: Comparisons by age and playing standard.

This study quantified and compared the collision and non-collision match characteristics across age categories (i.e. U12, U14, U16, U18, Senior) for both amateur and elite playing standards from Tier 1 rugby union nations (i.e. England, South Africa, New Zealand). Two-hundred and one male matches (5911 min ball-in-play) were coded using computerised notational analysis, including 193,708 match characteristics (e.g. 83,688 collisions, 33,052 tackles, 13,299 rucks, 1006 mauls, 2681 scrums, 2923 lineouts, 44,879 passes, 5568 kicks). Generalised linear mixed models with post-hoc comparisons and cluster analysis compared the match characteristics by age category and playing standard. Overall significant differences (p < 0.001) between age category and playing standard were found for the frequency of match characteristics, and tackle and ruck activity. The frequency of characteristics increased with age category and playing standard except for scrums and tries that were the lowest at the senior level. For the tackle, the percentage of successful tackles, frequency of active shoulder, sequential and simultaneous tackles increased with age and playing standard. For ruck activity, the number of attackers and defenders were lower in U18 and senior than younger age categories. Cluster analysis demonstrated clear differences in all and collision match characteristics and activity by age category and playing standard. These findings provide the most comprehensive quantification and comparison of collision and non-collision activity in rugby union demonstrating increased frequency and type of collision activity with increasing age and playing standard. These findings have implications for policy to ensure the safe development of rugby union players throughout the world.

The safety of rugby union, especially the tackle, has previously been questioned but limited data are available to understand the collision and non-collision match characteristics between different age categories and playing standards.The frequency of collision and non-collision match characteristics increase with age and playing standard except for the frequency of scrums and tries which are lowest at the Senior Elite level. The activity of the tackle and ruck are also different between age categories and playing standards.Hierarchical cluster analysis demonstrated clear differences in all and collision match characteristics between junior (i.e. U12, U14, U16), and amateur (i.e. U18 and senior) and elite (i.e. U18 and senior) playing levels.Governing bodies and practitioners should be aware of the differences in collision and non-collision match characteristics by age and playing standard, when reviewing future versions of rugby union.