A systematic review and meta-analysis of concussion in rugby union

The Incidence of Sports-Related Concussion in Children and Adolescents: A Systematic Review and Meta-Analysis

BACKGROUND

Sport-related concussions (SRC) are a concern for young athletes due to the potential for long-term health problems. This systematic review and meta-analysis aimed to provide a comprehensive overview of the literature exploring SRC incidence in youth sports to understand the associated risks.

METHODS

Medline, Embase, SPORTDiscus, PsycINFO, and Web of Science databases were searched without language restrictions up to September 2024. Studies were included if they (i) reported data for calculation of SRC incidence, (ii) were a prospective cohort study, and (iii) included a sample aged ≤ 18 years. Studies that reported Athlete Exposure (AE) or Player Hours (PH) as SRC incidence data measures were included in a multi-level random-effects meta-analysis. Additional analysis explored SRC incidence based on age, sex, country, year of data collection, setting, and level of contact.

RESULTS

Of the 6474 studies reviewed for eligibility, 116 studies were accepted for a systematic review and 99 in the meta-analysis. A total of 3,025,911 participants were included in the review (59% male, 41% female); however, 41% of studies did not report sample size. The pooled incidence rate of SRC per 1000 AE was found to be 1.41 across 21 sports, and 4.36 per 1000 PH across 7 sports. The highest incidence per 1000 AE were in taekwondo, rugby union, and ice hockey, and the highest incidence per 1000 PH were in rugby 7s, rugby league, and rugby union.

CONCLUSIONS

This systematic review and meta-analysis can serve as an updated baseline for risk of concussion among youth athletes across various sports.

TRIAL REGISTRATION

This systematic review was registered on OSF Registries ( https://osf.io/v298s ).

Exploring concussion prevalence, knowledge and reporting behaviours in women playing rugby union in the United Kingdom

OBJECTIVES

The aim of this study was to capture information regarding concussion prevalence, knowledge, and reporting behaviors in women rugby players across all competitive levels in the UK. We also investigated whether these outcomes were influenced by the prevailing concussion awareness programme (HEADCASE).

MEASURES

Two hundred and thirty players from elite (Premiership), Championship, British Universities, and College Sport and club level completed (n = 133) or partially completed (n = 97) a mixed-methods online questionnaire.

RESULTS

Over a mean period of 8 years, 159 players (74%) experienced at least one suspected or diagnosed rugby-related concussion. In total, 408 rugby-related concussions were reported in these players during this time. Prevalence of concussion did not differ across playing level or position. Being tackled was the most common cause of rugby-related concussions, and the act of tackling another player was second. Players across all levels demonstrated good knowledge of concussion symptoms, but only 12% identified that concussion can occur without direct impact to the head. One hundred and forty-six players completed the HEADCASE training (mandatory for Premiership players). Forty-one percent of players admitted to deliberately failing to report a suspected rugby concussion, and this behavior was not influenced by HEADCASE training. These individuals were more likely to avoid reporting a suspected concussion during an important (e.g. semifinal or final) than unimportant (e.g. training) scenario. Those who underwent the graduated return to play pathway (n = 41) were significantly more likely to have completed HEADCASE training.

CONCLUSION

The prevalence of concussion in women's rugby union is high but does not differ by playing level or position. All players had a good knowledge of concussion symptoms, but many were unaware that concussions may occur without direct impact to the head. Almost half of all players admitted to deliberately failing to report a suspected concussion, and this was not significantly influenced by the completion of HEADCASE training.

A cross-season analysis of S100B as a potential marker of concussion in professional rugby players

OBJECTIVES

To investigate the effect of multiple seasons of play on serum S100B concentration in male professional rugby players, while also assessing the acute effects following a season of play and concussion.

METHODS

A prospective study of professional male rugby players over three seasons (2016/17 to 2018/19) was conducted. Serum sampling was carried out during pre-season, post-season and following a concussion; sustained during match play at a home game (between 2-24hrs), during each season. Serum S100B concentrations were determined by ELISA assay.

RESULTS

Fourteen players sustained 24 concussions over three seasons, of which 13 samples (54%) were collected. Pre- and post-season serum S100B remained stable across multiple seasons. S100B concentration increased significantly following concussion compared with pre-season (p = 0.002) and post-season (p = 0.009), reflective in a 3.23-fold-change post-concussion, with no difference found between pre- and post-season values. S100B concentration measured at post-season was not significantly different for players who had a concussion during a season and players who did not.

CONCLUSION

S100B remains stable across multiple seasons of play in professional rugby players. As concussion results in a temporary increase in S100B concentration, returning to pre-season values by post-season, S100B may be a useful diagnostic marker for improving existing management protocols for sports-related concussions.

Performance of the Baseline Sport Concussion Assessment Tool in Male and Female Spanish Amateur Rugby Players

Background/Objectives: The Sport Concussion Assessment Tool (SCAT) is a test used to screen for suspected concussions, with the results compared to baseline values. If current baseline values are unavailable, they can be compared to baseline values obtained from professional rugby players. The aim of this study was to evaluate the baseline SCAT values in Hispanic community rugby players of both sexes. This cohort study used an observational, prospective, and descriptive design. Methods: Participants: A total of 81 female (age: 23.3 ± 3.3 years) and 138 male (age: 23.7 ± 4.3 years) Spanish rugby players who participated in national-level competitions. Interventions (or assessment of risk factors of independent variables): The SCAT was administered as part of the pre-season medical testing, including symptoms endorsed, cognitive submode performance, and balance performance. Results: Most of the Spanish community rugby players presented some symptom in the SCAT (male = 75.4%; female = 91.4%). The number and severity of the symptoms reported by the male players were lower than those reported by the female players (p = 0.001). The time to complete the tandem gait test and balance test showed differences between sexes (p < 0.001). Conclusions: The baseline SCAT values of Spanish community rugby players differ from those of professional players, leading to the recommendation of conducting the SCAT for all players before the beginning of the season. If baseline evaluations cannot be performed, the results obtained could serve as a basis for developing reference values for community rugby in the Hispanic population. Recording the menstrual cycle phase during which the SCAT is performed may help improve its interpretation.

The effect of assessor expertise on reliability of analysis of video signs associated with concussion in Australian football

OBJECTIVES

To determine whether spotters with medical training and experience in managing concussion have higher inter-rater reliability and accuracy than non-medical personnel when identifying video signs associated with concussion in Australian football.

DESIGN

Retrospective cohort study.

METHODS

Video clips were collected of all impacts potentially resulting in concussion during 2012 and 2013 Australian Football League (AFL) seasons. Raters were divided into medical doctors and a non-medical group comprising allied health practitioners (physiotherapists) and non-medical/non-allied health personnel (performance analysts). Raters assessed 102 randomly selected videos for signs of concussion. The inter-rater reliability was calculated. Sensitivity, specificity, positive and negative predictive values were calculated by comparing the rater responses to the consensus opinion from two highly experienced clinicians with expertise in concussion.

RESULTS

No statistically significant difference in inter-rater reliability was observed between the medical doctors and the non-medical group. Both groups demonstrated good to excellent agreement for slow to get up, clutching at head/face and facial injury. Both groups displayed intra-class coefficient >0.55 for no protective action-floppy, loss of responsiveness, and motor incoordination, and displayed lowest agreement for no protective action-tonic posturing, impact seizure and blank/vacant look. No statistically significant difference was found between the groups for sensitivity, specificity, positive and negative predictive values for correctly classifying video signs compared to the expert consensus opinion.

CONCLUSIONS

After completing sufficient standardised training and testing, medical and non-medical personnel demonstrate comparable reliability in identifying video signs of concussion in professional Australian football and may be suitable for the role of video spotter.

'Mental heAlth and well-being in rUgby pLayers' (MAUL) study: an online survey of diverse cohorts of rugby union players internationally

Introduction

Mental health and well-being is a relatively under-researched area in rugby, especially outside the elite men's game. Evidence suggests that physical activity and sports benefit mental health and well-being, and rugby provides health-enhancing moderate-to-vigorous physical activity.

Objective

This cross-sectional study used an online approach and engaged national rugby governing bodies to understand adult rugby players' mental health and well-being and increase the diversity of the current evidence base.

Results

500 rugby players completed an online survey. 44% of participants identified as female, and 55% as male. The UK (67%), Ireland (15%) and South Africa (12%) were the countries with the highest representation. 71% of participants were amateur players, with elite players making up 20% of the population. 87% of players participated in contact forms of the game, with 9% predominantly playing non-contact rugby. Over 50% of participants reported that rugby impacted 'extremely' positively on both their mental health and well-being. Based on the Kessler psychological distress scale (K10), 57.8% of all respondents belonged to the 'psychologically well' group. Males were more likely to belong to this group than females (p=0.01). Non-contact and amateur players had lower scores of psychological distress than contact and professional players (p=0.001 and p=0.006), respectively. Non-contact players had higher well-being (Short Warwick-Edinburgh Mental Well-being Scale) scores than contact players (p<0.001).

Conclusion

This study provides new insights into the mental health and well-being of a diverse group of rugby players.

Decreased isometric neck strength is a risk factor for head, neck and face injuries in professional rugby league players

Head, neck and face injuries are a concern in contact sports. This exploratory study aimed to establish 1) injury risk factors for head, neck and face injuries and 2) clinical cut-off values related to strength, endurance and proprioception of the cervical spine in a team of professional rugby league players. Pre-season assessments of isometric strength of the flexor, extensor and lateral flexor muscles, endurance of the flexor muscles and joint position error were conducted. Injuries resulting in games missed were recorded. Cross-tabulations were used to determine the unadjusted odds ratios for the measures as risk factors for playing season injuries. The unadjusted odds ratio (OR) values indicated that if a player had weaker extensors of the neck (<36.4 kg, p = 0.014; <3.4N/kg, p = 0.014) or asymmetry of isometric strength of their lateral flexor muscles (left-to-right ratio <0.91, p = 0.005), their odds of games missed due to season head, neck and face injuries was increased (OR extensors = 8; 95% CI = 1.5-42.5 OR asymmetry of lateral flexor muscles OR = 12.6; 95% CI = 2.0-79.4). As muscle strength is modifiable, the clinical application of this study would involve targeting players in the team beneath the clinical cut-off value.

A comparison of head impact characteristics during elite men's Rugby Union fifteens and sevens match play

Different forms of rugby may pose distinct risks to head injury. Video of rugby match footage was analyzed using head impact magnitude, frequency, and time interval for 15s and 7s athletes. Impacts were reconstructed in laboratory, and finite element modeling was used to estimate maximum principal strain. No difference was found in impact frequency or time interval between the two forms. Significantly more head impacts of higher severity levels were documented during 7s. These findings provide objective comparisons between 7s and 15s which may guide risk mitigation strategies in managing brain trauma for specific forms of rugby.

Injury Profiling in Male Police Cadets During Initial Training Phase: A Retrospective Cohort Study

Musculoskeletal injuries during the "Initial Training Phase" (ITP) are a major medical problem faced by law enforcement agencies worldwide. Aiming to develop an injury prevention strategy, we examined the incidence, type, associated factors, and severity of injuries and secondarily tracked their evolution over time by batches in a police academy. A retrospective cohort study was conducted using prospectively collected injury data on 979 newly recruited male police cadets enrolled in eight batches between 2015 and 2023. Among the 376 injured participants (age: 18.1 ± 0.3 years, body-mass: 75.8 ± 12.5 kg, body-height: 173.7 ± 4.0 cm, body mass index [BMI]: 25.1 ± 4.1 kg·m-2, body-fat percentage: 18.1% ± 5.1%), 405 injuries were recorded during the ITP. Musculoskeletal injury data were analyzed according to type, associated-factors, severity, and evolution across batches. Almost half of the recruits (41.4%) sustained at least one musculoskeletal injury. Based on injury frequency (39-69 case) and exposure time (20,944.5-43,006.5 hours per participant) indices, and with an implication of scientific training tips, the long-term follow-up over-batches showed that the injury incidence was decreased 2.5-fold from Batch 1 to Batch 8 (p < .0001). Most injuries occurred between Weeks 2 and 5 (80% cumulative). The most common injury type was medial tibial stress syndrome (36.0%), followed by iliotibial band syndrome (12.6%), and ankle sprain (10.4%). This injury profile aligns with previous studies on law enforcement recruits, although comparisons should be made cautiously due to variations in training programs and recruit characteristics between agencies. The most frequently reported perceived potential contributors of injuries were vitamin and mineral deficiencies (20.7%), overweight/obesity (19.1%), and harsh physical activities (13.0%). During ITP, almost half of the recruits sustained at least one musculoskeletal injury, most of them in the fourth week. Some of the major associated factors of injury could be controlled resulting in a potential reduction of the injury incidence by up to 2.5 times. Implementing tailored fitness programs, incorporating subjective and objective training load assessments, and enhancing monitoring could significantly decrease injury rates, improve recruit readiness, and reduce resource and time waste on injury treatment.

Concussion Incidence by Type of Sport: Differences by Sex, Age Groups, Type of Session, and Level of Play An Overview of Systematic Reviews With Meta-analysis

OBJECTIVES: To (1) summarize pooled prevalence and incidence rates of concussion by type of sport and (2) synthesize the differences in prevalence or incidence rates of concussion by type of sports in terms of sex, age, type of session, and level of competition. DESIGN: An overview of systematic reviews with meta-analysis. LITERATURE SEARCH: CINAHL, Embase, Epistemonikos, PubMed, Scopus, SPORTDiscus, and the Cochrane Library databases were searched. STUDY SELECTION CRITERIA: Systematic reviews with meta-analyses reporting pooled incidence or prevalence of sport-related concussion. DATA SYNTHESIS: AMSTAR 2 was used to assess the methodological quality of reviews. Overlap between reviews was calculated. RESULTS: Ten systematic reviews with meta-analysis were included, all evaluating incidence rates of concussion. There were no meta-analyses of concussion prevalence. Concussions seem to have a higher incidence in rugby, snowboarding, ice hockey, and American football. In reviews that explored sex-based differences across subgroups, there was a higher incidence rate of concussion in baseball-softball, basketball, and soccer in females compared to males. There were no age subgroups analyzed. The incidence of concussions was higher during games compared to practice in American football, ice hockey, rugby, and soccer. Amateur rugby had higher concussion rates compared to professional rugby. CONCLUSIONS: Rugby, snowboarding, ice hockey, and American football had the highest incidence rate of concussion when no other differences (eg, type of session) were considered. However, important methodological flaws were detected, such as the lack of use of the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) system and subgroups for specific factors (eg, age groups). J Orthop Sports Phys Ther 2024;54(11):1-9. Epub 15 October 2024. doi:10.2519/jospt.2024.12677.

Studying Contact Replays: Investigating Mechanisms, Management and Game Exposures (SCRIMMAGE) for brain health in the Australasian National Rugby League: a protocol for a database design

Concussions in contact sports are challenging for athletes, health professionals and sporting bodies to prevent, detect and manage. Design of interventions for primary prevention, early recognition of concussion and continuing to improve postconcussion management are essential for protecting athletes and promoting brain health. Over the last decade, there have been advancements in video technology for analysing head impact events and improvements in the clinical management of concussions. This study protocol describes how researchers, clinicians and staff from the Australasian National Rugby League (NRL) have brought these advancements together and developed a database of videos with head impact events and clinical outcomes. The intended outputs from this work will enhance the understanding of head impact events in NRL, from biomechanical and gameplay factors to concussion and return to play outcomes. Publishing this protocol increases the transparency of this large-scale effort to better identify head impacts and their relationship to concussions and player movement behaviour to contextualise these variables to generate new knowledge and support the reproducibility of these emerging findings. Between 2017 and 2023, over 5250 head contact cases were recorded in the database, from which >1700 head injury assessments were performed, and >600 concussions were diagnosed. Future studies using these data are planned to inform both primary and secondary injury prevention initiatives, such as risk analysis and prediction of game scenarios that result in concussion, as well as investigation of features and factors that help to inform the duration of recovery and return to play.

Gender differences in female and male Australian football concussion injury: A prospective observational study of emergency department presentations

OBJECTIVE

To examine gender differences in Australian football (AF)-related concussion presentations to EDs in regional Australia.

METHODS

A prospective observational study of patients presenting to 1 of the 10 EDs in Western Victoria, Australia, with an AF-related concussion was conducted. Patients were part of a larger study investigating AF injuries over a complete AF season, including pre-season training and practice matches. Information regarding concussion injuries was extracted from patient medical records, including clinical features, concurrent injuries, mechanism and context of injury. Female and male data were compared with chi-squared and Fisher's exact tests. P < 0.05 was considered significant.

RESULTS

From the original cohort of 1635 patients with AF-related injuries (242 female and 1393 male), 231 (14.1%) patients were diagnosed with concussion. Thirty-eight (15.7%) females had concussions versus 193 (13.9%) males (P > 0.05). Females over the age of 16 were more likely to be concussed than males in the same age range (females n = 26, 68.4% vs males n = 94, 48.7%; P = 0.026). Neurosurgically significant head injury was rare (one case). Similar rates of concurrent injury were found between females 15 (39.5%) and males 64 (33.2%), with neck injury the single most common in 24 (10.3%) concussions. Sixty-nine patients (29%) were admitted for observation or to await the results of scans. The majority of concussions occurred in match play (87.9%). Females were more likely injured in contested ball situations (63.2% vs 37.3%; P < 0.05).

CONCLUSION

Concussion rates for community-level AF presentations to regional EDs were similar between genders. Serious head injury was rare, although hospital admission for observation was common. Concurrent injuries were common, with associated neck injury most often identified. Match play accounted for the majority of head injuries.

Potential of Soft-Shelled Rugby Headgear to Lower Regional Brain Strain Metrics During Standard Drop Tests

BACKGROUND

The growing concern for player safety in rugby has led to an increased focus on head impacts. Previous laboratory studies have shown that rugby headgear significantly reduces peak linear and rotational accelerations compared to no headgear. However, these metrics may have limited relevance in assessing the effectiveness of headgear in preventing strain-based brain injuries like concussions. This study used an instantaneous deep-learning brain injury model to quantify regional brain strain mitigation of rugby headgear during drop tests. Tests were conducted on flat and angled impact surfaces across different heights, using a Hybrid III headform and neck.

RESULTS

Headgear presence generally reduced the peak rotational velocities, with some headgear outperforming others. However, the effect on peak regional brain strains was less consistent. Of the 5 headgear tested, only the newer models that use open cell foams at densities above 45 kg/m3 consistently reduced the peak strain in the cerebrum, corpus callosum, and brainstem. The 3 conventional headgear that use closed cell foams at or below 45 kg/m3 showed no consistent reduction in the peak strain in the cerebrum, corpus callosum, and brainstem.

CONCLUSIONS

The presence of rugby headgear may be able to reduce the severity of head impact exposure during rugby. However, to understand how these findings relate to brain strain mitigation in the field, further investigation into the relationship between the impact conditions in this study and those encountered during actual gameplay is necessary.

Levels of biomarkers associated with subconcussive head hits in mixed martial arts fighters

Background

Concussion and the damage resulting from this event related to brain function have been widely studied; however, little is known about subconcussive impacts, especially in Mixed Martial Arts (MMA) fighters, which is a combat and full contact sport in which most blows are aimed at the head.

Objective

This study aims to evaluate the biomarker levels associated with subconcussive hits to the head in MMA fighters.

Methods

This is an exploratory study in which 30 male subjects (10 MMA fighters, 10 healthy individuals who practice muscle training, and 10 healthy sedentary individuals) aged between 18 and 32 years (25.4 ± 3.8) were evaluated. These individuals underwent blood collection to assess their Ubiquitin C-terminal hydrolase (UCH-L1), Glial Fibrillary Acidic Protein (GFAP) and Brain Derived Neurotrophic Factor (BDNF) levels before, immediately after and 72 hours after the sparring session (for the fighters) and were compared between groups.

Results

Significant differences were found at baseline between active and healthy fighters in BDNF levels (p = 0.03). A significant reduction of BDNF levels were also observed between the post-immediate and 72h after the sparring session (p = 0.03). No differences were observed in the number or severity of symptoms reported by the fighters.

Conclusion

Despite the exploratory approach, the findings of this study may help to understand the influence of repeated subconcussive hits to the head in MMA fighters, as well as to propose preventive interventions which can minimize the effects of the impact of hits, preserving fighters' neuronal integrity and function.

The Impact of Drop Test Conditions on Brain Strain Location and Severity: A Novel Approach Using a Deep Learning Model

In contact sports such as rugby, players are at risk of sustaining traumatic brain injuries (TBI) due to high-intensity head impacts that generate high linear and rotational accelerations of the head. Previous studies have established a clear link between high-intensity head impacts and brain strains that result in concussions. This study presents a novel approach to investigating the effect of a range of laboratory controlled drop test parameters on regional peak and mean maximum principal strain (MPS) predictions within the brain using a trained convolutional neural network (CNN). The CNN is publicly available at https://github.com/Jilab-biomechanics/CNN-brain-strains . The results of this study corroborate previous findings that impacts to the side of the head result in significantly higher regional MPS than forehead impacts. Forehead impacts tend to result in the lowest region-averaged MPS values for impacts where the surface angle was at 0° and 45°, while side impacts tend to result in higher regional peak and mean MPS. The absence of a neck in drop tests resulted in lower regional peak and mean MPS values. The results indicated that the relationship between drop test parameters and resulting regional peak and mean MPS predictions is complex. The study's findings offer valuable insights into how deep learning models can be used to provide more detailed insights into how drop test conditions impact regional MPS. The novel approach used in this paper to predict brain strains can be applied in the development of better methods to reduce the brain strain resulting from head accelerations such as protective sports headgear.

Cumulative effects of subsequent concussions on the neural patterns of young rugby athletes: data from event-related potentials

Our study aimed at detecting a potential cumulative effect of subsequent concussions on the neural activation patterns of young rugby athletes with or without concussion history. Event-related brain potential (ERP) data from 24 rugby players, 22-year-old on average, were retrospectively examined. All underwent a Sport Concussion Assessment Tool (SCAT2) during preseason and an on-site ERP task (P300) following a recent concussion event (<48 hours). Sixteen players suffered at least one concussion in the previous 3 years and eight were without self-reported past concussion. While no differences were reported between groups regarding symptom appraisal on the SCAT2 assessment, ERP revealed significantly decreased P3b amplitude and a trend for increased P3b latency in players who experienced prior concussions. Our data thus support the cumulative effect of concussions on neuroelectric events in young rugby players, highlighting the importance of managing player's concussion load to reduce the risk of long-term injuries.

High school rugby coaches' knowledge and opinions of concussion in Kwa-Zulu Natal province in South Africa: an ecological cross-sectional study

BACKGROUND

Concussions in Rugby Union are common with an increased risk to adolescent players. Coaches are key to injury prevention and a greater understanding of their knowledge and sentiments may guide future initiatives. There is a lack of data on rugby coaches, especially in South Africa. This study aimed to investigate the knowledge and opinions of high school rugby coaches regarding concussion management.

METHODS

This cross-sectional study of 37 high school rugby coaches in South Africa, was conducted via a self-reported questionnaire. Concussion knowledge was scored for correct answers only with closed-question scaling methods to measure the importance of items of concussion management using a graphical rating scale. An attitude scale (Likert) was used to assess self-reported opinions and behaviours. Associations were calculated for participant characteristics and overall concussion injury knowledge.

RESULTS

More participants showed good overall knowledge of ≥ 75% (n = 22, 59% vs. n = 15, 40%), especially those with greater coaching experience (p = 0.021). Player welfare was perceived more important than player performance (185 vs. 164), with concussion prevention most important (184 of 185). Appealing characteristics of an injury prevention programme were the improvement of player skill (173, SD ± 0.75, mean 4.68), being adaptable (171, ± 0.86, 4.62), and being completed in the warm-up (167, ± 0.93, 4.51). The biggest perceived barriers were duration (138, ± 1.59, mean 3.73), effort (130, ± 1.56, 3.51), compliance and lack of knowledge (both 127, ± 1.68, 3.43).

CONCLUSION

These results support the implementation of ongoing concussion education for rugby coaches and identify areas for promoting awareness and knowledge of concussion injury prevention, identification, and specific management of younger athletes. Appealing characteristics and barriers are highlighted and may allow for improved implementation and adherence to concussion prevention programmes.

Are Sex Differences in Collegiate and High School Sports-Related Concussion Reflected in the Guidelines? A Scoping Review

Background: Sport-related concussion (SRC) is a common sport injury. Females are participating in sports at increasing rates, and there is growing awareness that female athletes may be more vulnerable to SRC. Objectives: We aimed to identify sex differences in epidemiology, clinical manifestation and assessment of SRC and examine how these relate to the 6th International Conference on Concussion in Sport (ICCS). Methods: We conducted a scoping review of the Medline database and identified 58 studies examining the effects of sex on SRC in collegiate and high school athletes that were written in English and published in a peer-reviewed journal between March 2012 and March 2022. Results: We found that female athletes suffer higher rates of concussion in sex-comparable sports, in particular soccer. Female athletes experience more somatic symptoms-headache/migraine/sleep disturbance-and may take longer to recover from concussion. Sex differences were also identified regarding some aspects of sideline concussion assessment with the Sport Concussion Assessment Tool. Conclusions: Females are at greater risk and experience SRC differently than males; this is mostly likely due to a combination of biomechanical factors, differences in neck musculature and hormonal and social factors. Sex differences are not widely addressed by the 6th ICSS, which informs many sports' concussion protocols.

Concussion-Associated Gene Variant COMT rs4680 Is Associated With Elite Rugby Athlete Status

OBJECTIVE

Concussions are common match injuries in elite rugby, and reports exist of reduced cognitive function and long-term health consequences that can interrupt or end a playing career and produce continued ill health. The aim of this study was to investigate the association between elite rugby status and 8 concussion-associated risk polymorphisms. We hypothesized that concussion-associated risk genotypes and alleles would be underrepresented in elite rugby athletes compared with nonathletes.

DESIGN

A case-control genetic association study.

SETTING

Institutional (university).

PARTICIPANTS

Elite White male rugby athletes [n = 668, mean (SD) height 1.85 (0.07) m, mass 102 (12) kg, and age 29 (7) years] and 1015 nonathlete White men and women (48% men).

INTERVENTIONS

Genotype was the independent variable, obtained by PCR of genomic DNA using TaqMan probes.

MAIN OUTCOME MEASURE

Elite athlete status with groups compared using χ 2 and odds ratio (OR).

RESULTS

The COMT rs4680 Met/Met (AA) genotype, Met allele possession, and Met allele frequency were lower in rugby athletes (24.8%, 74.6%, and 49.7%, respectively) than nonathletes (30.2%, 77.6%, and 54.0%; P < 0.05). The Val/Val (GG) genotype was more common in elite rugby athletes than nonathletes (OR 1.39, 95% confidence interval 1.04-1.86). No other polymorphism was associated with elite athlete status.

CONCLUSIONS

Elite rugby athlete status is associated with COMT rs4680 genotype that, acting pleiotropically, could affect stress resilience and behavioral traits during competition, concussion risk, and/or recovery from concussion. Consequently, assessing COMT rs4680 genotype might aid future individualized management of concussion risk among athletes.

Sport level and sex differences in sport-related concussion among Japanese collegiate athletes: Epidemiology, knowledge, reporting behaviors, and reported symptoms

This study investigated the incidence of sport-related concussion (SRC) in sports, effect of athlete knowledge on reporting behavior differences between collegiate and non-collegiate athletes, and differences in SRC symptoms between sexes and level of participation. In this cross-sectional survey, 1 344 Japanese collegiate and non-collegiate athletes from a single institute were analyzed. Using a web-based survey, demographics, general SRC, knowledge of SRC, the most recent SRC reporting behaviors, and symptom presentation were examined. The prevalence of SRC during the academic year 2016-2017 was 2.68 (95% confidence interval [CI]: 1.88-3.69) across all sports. The prevalence of SRC was 33.3 (95% CI: 17.96-51.83) in rugby union and 8.33 (95% CI: 1.03-27.00) in women's soccer. The prevalence of SRC in males (3.47 [95% CI: 2.38-4.86] was 3.65 times higher than that in females (0.95 [95% CI: 0.26-2.41]). In total, the mean total score of knowledge was 5.30 (4.2) across 25 questions; dizziness was the most well-known symptom (867/1 344, 64.5%), followed by headache (59.3%). Being more emotional (44/1 345, 3.3%) was the least frequently known symptom. Level of participation did not affect scores (5.16 [3.96] vs. 5.52 [4.54]; p ​= ​0.131). All 87 disclosing participants experienced drowsiness and irritability and felt more emotional. In terms of sex and participant level, no significant differences were found in any symptoms. This study found very low rates of concussion education in Japan. Dissemination of concussion education is essential in the future to recognize concussion earlier and prevent severe concussive injury.

Lower systemic nitric oxide bioactivity, cerebral hypoperfusion and accelerated cognitive decline in formerly concussed retired rugby union players

NEW FINDINGS

What is the central question of this study? What are the molecular, cerebrovascular and cognitive biomarkers of retired rugby union players with concussion history? What is the main finding and its importance? Retired rugby players compared with matched controls exhibited lower systemic nitric oxide bioavailability accompanied by lower middle cerebral artery velocity and mild cognitive impairment. Retired rugby players are more susceptible to accelerated cognitive decline.

ABSTRACT

Following retirement from sport, the chronic consequences of prior-recurrent contact are evident and retired rugby union players may be especially prone to accelerated cognitive decline. The present study sought to integrate molecular, cerebrovascular and cognitive biomarkers in retired rugby players with concussion history. Twenty retired rugby players aged 64 ± 5 years with three (interquartile range (IQR), 3) concussions incurred over 22 (IQR, 6) years were compared to 21 sex-, age-, cardiorespiratory fitness- and education-matched controls with no prior concussion history. Concussion symptoms and severity were assessed using the Sport Concussion Assessment Tool. Plasma/serum nitric oxide (NO) metabolites (reductive ozone-based chemiluminescence), neuron specific enolase, glial fibrillary acidic protein and neurofilament light-chain (ELISA and single molecule array) were assessed. Middle cerebral artery blood velocity (MCAv, doppler ultrasound) and reactivity to hyper/hypocapnia (CVR CO 2 hyper ${\mathrm{CVR}}_{{\mathrm{CO}}_{\mathrm{2}}{\mathrm{hyper}}}$ /CVR CO 2 hypo ${\mathrm{CVR}}_{{\mathrm{CO}}_{\mathrm{2}}{\mathrm{hypo}}}$ ) were assessed. Cognition was determined using the Grooved Pegboard Test and Montreal Cognitive Assessment. Players exhibited persistent neurological symptoms of concussion (U = 109(41) , P = 0.007), with increased severity compared to controls (U = 77(41) , P < 0.001). Lower total NO bioactivity (U = 135(41) , P = 0.049) and lower basal MCAv were apparent in players (F2,39  = 9.344, P = 0.004). This was accompanied by mild cognitive impairment (P = 0.020, 95% CI, -3.95 to -0.34), including impaired fine-motor coordination (U = 141(41) , P = 0.021). Retired rugby union players with history of multiple concussions may be characterised by impaired molecular, cerebral haemodynamic and cognitive function compared to non-concussed, non-contact controls.

Post-concussion syndrome and concussion incidence improved in a pro rugby player following cervical spine rehab: case study and 6-year follow-up

Aim

To report improvements in post-concussion syndrome and concussion incidence following cervical spinal alignment correction.

Case presentation

A 27-year-old professional rugby player with 20 documented concussions presented with abnormal cervical spinal alignment and post-concussion syndrome. After 30 sessions of cervical rehabilitation, health outcomes improved. Post-treatment radiographs showed improved cervical lordosis from -13.5° to -37.4° (ideal is -42°) and right head translation from -22.7 to -11.3 mm (ideal is 0 mm). 2-year follow-up radiographs and 6-year follow-up health outcomes showed post-treatment improvements were maintained. The patient reported two documented concussions in the 6 years following treatment while maintaining the same lifestyle and professional rugby career.

Conclusion

Correction of abnormal cervical spinal alignment may help athletes with post-concussion syndrome and reduce risk of concussion.

A comparison of clinical assessment with common diagnostic tools for monitoring concussion recovery in adolescent rugby union players

OBJECTIVES

To characterise the incidence, severity and recovery of sport-related concussion (SRC) in schoolboy rugby players and explore whether the Sports Concussion Assessment Tool (SCAT), Cogstate Brief Battery (CBB) and the King-Devick test (K-D test) can be used to monitor concussion status through to full recovery.

DESIGN

Prospective cohort study.

SETTING

Rugby union has a high rate of SRC; however, there is little research investigating how concussion affects adolescent rugby players.

PARTICIPANTS

Schoolboy rugby players.

MAIN OUTCOME MEASURES

Participants completed baseline tests in the preseason. Participants diagnosed with SRC during the season attended for post-concussion testing on a weekly basis until recovered.

RESULTS

135 schoolboy rugby players (16.7 ± 0.82y) participated in the study. There were 18 SRCs in 16 participants. Concussion incidence was 9/1000 player hours. CBB and K-D tests were poorly associated with clinical assessment and produced high false negative rates (0.58 and 0.52 respectively).

CONCLUSIONS

This study reports a relatively high match SRC incidence for an adolescent population. Analysis of clinical recovery with CBB and K-D test revealed a relatively poor ability to accurately monitor concussion status compared to clinical assessment suggesting that these tools should not be used in isolation for monitoring SRC recovery in adolescents.

Soft-shell headgear in rugby union: a systematic review of published studies

Objectives

To review the rate of soft-shell headgear use in rugby union, consumer knowledge of the protection potential of soft-shell headgear, incidence of concussion reported in rugby headgear studies, and the capacity of soft-shell headgear to reduce acceleration impact forces.

Design

A systematic search was conducted in July and August 2021 using the databases SPORT Discus, PubMed, MEDLINE, CINAHL (EBSCO), Scopus, and Science Direct. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The protocol for this systematic review was registered on PROSPERO (registration number: CRD42021239595).

Outcome measures

Rates of headgear use, reports of estimated protection of headgear against head injury, incidence of concussion and magnitude of impact collisions with vs. without headgear, impact attenuation of headgear in lab studies.

Results

Eighteen studies were identified as eligible: qualitative (N = 4), field (N = 7), and lab (N = 7). Qualitative studies showed low rates of headgear use and varying understanding of the protection afforded by headgear. Field studies showed negligible association of headgear use with reduced impact magnitude in headgear vs. non-headgear cohorts. Lab studies showed increased energy attenuation for thicker headgear material, poorer performance of headgear after repetitive impacts and increased drop heights, and promising recent results with headgear composed of viscoelastic polymers.

Conclusions

Rates of adoption of soft-shell headgear remain low in rugby and any association between its use and reduction in acceleration impact forces remains unclear. Lab results indicating improved impact attenuation need to be validated in the field. Further headgear-related research is needed with youth and female rugby players.

Blood Biomarkers for Return to Play after Concussion in Professional Rugby Players

We prospectively evaluated a panel of seven blood biomarkers (S100 calcium-binding protein B [S100B], neuron specific enolase [NSE], spectrin breakdown products [SBDP], ubiquitin C-terminal hydrolase L1 [UCHL1], glial fibrillary acidic protein [GFAP], neurofilament light chain [NFL], and tubulin-associated unit [Tau]) for sport-related concussion (SRC) in a large multi-centric cohort of 496 professional rugby players from 14 French elite teams. Players were sampled twice during the season (beginning and end) away from any sport practice. From these two baseline samples, we evaluated the intra-individual variability to establish the effect of rugby on blood biomarkers over a season. Only S100B and GFAP remained stable over the course of a season. During the period of the study, a total of 45 SRC cases was reported for 42 players. In 45 SRCs, the head injury assessment (HIA) process was performed and blood collection was realized 36 h after the concussion (HIA-3 stage). For each biomarker, raw concentrations measured 36 h after SRC were not significantly different between players with a non-resolutive SRC (n = 28) and those with a resolutive SRC (n = 17; p between 0.06 and 0.92). In a second step, blood concentrations measured 36 h after SRC were expressed according to the basal concentrations as an individual percentage change (PCH36[%]), calculated as follows: PCH36 = 100 × (([Biomarker]36h - [Biomarker]basal)/[Biomarker]basal). S100B and NFL concentrations expressed as PCH36[%] were significantly different between non-resolutive and resolutive SRCs (p = 0.006 and 0.01 respectively), with a positive delta found in non-resolutive SRCs. Among the two biomarkers, it is important to note that only the S100B protein was stable during the season. In the context of our study, during HIA-3 assessment, S100B seems to perform better than NSE, SBDP, UCHL1, GFAP, NFL, and Tau as biomarker for SRC. From a clinical standpoint, the S100B modification over baseline may be valuable, at 36 h after concussion to distinguish non-resolutive SRC from resolutive SRC.

Neurodegenerative disease risk among former international rugby union players

BACKGROUND

Autopsy studies of former contact sports athletes, including soccer and rugby players, frequently report chronic traumatic encephalopathy, a neurodegenerative pathology associated with traumatic brain injury. Nevertheless, little is known about the risk of neurodegenerative disease in these populations. We hypothesised that neurodegenerative disease risk would be higher among former elite rugby union players than the general population.

METHODS

We conducted a retrospective cohort study accessing national electronic records on death certification, hospital admissions and dispensed prescriptions for a cohort of 412 male Scottish former international rugby union players and 1236 members of the general population, matched to former players by age, sex and area socioeconomic status. Mortality and incident neurodegenerative disease diagnoses among former rugby players were then compared with the matched comparison group.

RESULTS

Over a median 32 years follow-up from study entry at age 30 years, 121 (29.4%) former rugby players and 381 (30.8%) of the matched comparison group died. All-cause mortality was lower among former rugby players until 70 years of age with no difference thereafter. During follow-up, 47 (11.4%) former rugby players and 67 (5.4%) of the comparison group were diagnosed with incident neurodegenerative disease (HR 2.67, 95% CI 1.67 to 4.27, p<0.001).

CONCLUSIONS

This study adds to our understanding of the association between contact sports participation and the risk of neurodegenerative disease. While further research exploring this interaction is required, in the meantime strategies to reduce exposure to head impacts and head injuries in sport should be promoted.

International perspectives on trends in paediatric sports-related concussion: knowledge, management, unanswered questions

Purpose

In the last 20 years, concussion has received increased attention in the media, with distinct recognition of sports-related concussion (SRC). Much of this attention has centred on the paediatric population, due to concerns over adolescent brain development and the high numbers of teenagers playing contact sport. This qualitative study explored (1) what experts in the field of concussion perceive regarding trends in paediatric concussion awareness and management, and (2) how responses to these questions differ by country (US vs. NZ) and by discipline (research vs. sports coaching vs. sports medicine).

Methods

After the development of a semi-structured interview template, questions were coded for interviews of six (N = 6) experts in academia, medicine, and coaching: three in the United States (N = 3) and three in New Zealand (N = 3). Interviews were then transcribed and qualitatively analysed using a thematic narrative analysis. Emergent themes included concussion knowledge, management, and unanswered questions.

Results

Findings showed general commonalities on the importance of concussion education, the improvement of concussion awareness, compliance to concussion protocols, and the need to research long-term outcomes. Fewer commonalities were found regarding the level of concussion reporting, the impact of multiple concussions, whether paediatric and adult concussion should be treated similarly, and the utility of concussion tests.

Conclusions

Concussion experts agree on many areas; however, divergent opinions were apparent. Further original research is required within the paediatric population to analyse the efficacy of current concussion guidelines.

Match Injuries in the Spanish Rugby Union Division de Honor

OBJECTIVE

To describe the injury rate, severity, cause, anatomical location (tissue damaged), recurrence, place and time during matches throughout a season in the Spanish Rugby Union Division de Honor.

METHODS

Observational, prospective and descriptive study conducted in the competition of the Spanish División de Honor de Rugby with 258 players. The data were reported by the medical services of the previously formed clubs.

RESULTS

Total exposure was 4100 h, during which 220 injuries occurred. The average number of sick days was 36.8. The total injury rate was 53.6 injuries/1000 h of exposure. Three quarters suffered 93 injuries and the forwards sustained a total of 127 injuries, with a total of 48.6 and 58.1 injuries/1000 h of exposure, respectively. Moderate injuries were the most frequent. Specifically, ligament injury was the most frequent, and dislocation was the injury that caused the most sick days. The most injuries occurred in the third quarter of the match, and the most serious injuries occurred in the second quarter.

CONCLUSIONS

The injury rate of Spanish rugby competitors is 53.6 injuries/1000 match hours, with an average of 36.8 sick days. Contact injuries are the most frequent, taking place especially when tackling or being tackled.

Tacklers' Head Inertial Accelerations Can Be Decreased by Altering the Way They Engage in Contact with Ball Carriers' Torsos

PURPOSE

This study aimed to investigate how four types of successfully executed, legal front-on, one-on-one torso tackles influence the tacklers' and ball carriers' inertial head kinematics.

METHODS

A total of 455 successful front-on, one-on-one torso tackle trials completed by 15 rugby code players using three-dimensional motion capture were recorded. Tackles differed with respects to the height of the contact point on the ball carrier's torso. A series of mixed general linear models were conducted.

RESULTS

The tackler sustained the highest peak resultant linear ( P < 0.001) and angular ( P < 0.01) head accelerations when contacting the lower torso to execute a "dominant" tackle compared with mid or upper torso, although these latter tackle types had the lowest ball carrier inertial head kinematics. When executing a "smother" tackle technique, a significant decrease in peak resultant linear head acceleration was observed with a vertical "pop" then lock action used, compared with the traditional upper torso tackling technique ( P < 0.001).

CONCLUSIONS

Modifying the tackler's engagement with a ball carrier's torso, with respect to height and technical execution, alters the inertial head kinematics of the tackler and the ball carrier. The traditional thinking about optimal tackle technique, as instructed, may need to be reevaluated, with the midtorso being a potential alternative target contact height, whereas changes in tackle execution may be relatively protective for tacklers when executing either a dominant or smother tackle. This study provides critical scientific evidence to underpin revised coaching tackling technique interventions that might enhance player safety. Tackles in which the tackler contacts the ball carrier around the midtorso region, rather than lower torso, produce the lowest acceleration and thus may contribute to reducing head injury risk for the tackler.

Drop Test Kinematics Using Varied Impact Surfaces and Head/Neck Configurations for Rugby Headgear Testing

World Rugby employs a specific drop test method to evaluate headgear performance, but almost all researchers use a different variation of this method. The aim of this study was, therefore, to quantify the differences between variations of the drop testing method using a Hybrid III headform and neck in the following impact setups: (1) headform only, with a flat steel impact surface, approximating the World Rugby method, (2 and 3) headform with and without a neck, respectively, onto a flat MEP pad impact surface, and (4) headform and neck, dropped onto an angled MEP pad impact surface. Each variation was subject to drop heights of 75-600 mm across three orientations (forehead, side, and rear boss). Comparisons were limited to the linear and rotational acceleration and rotational velocity for simplicity. Substantial differences in kinematic profile shape manifested between all drop test variations. Peak accelerations varied highly between variations, but the peak rotational velocities did not. Drop test variation also significantly changed the ratios of the peak kinematics to each other. This information can be compared to kinematic data from field head impacts and could inform more realistic impact testing methods for assessing headgear.

Multisensory perception is not influenced by previous concussion history in retired rugby union players

BACKGROUND

To assess whether concussion history adversely affects multisensory integration, we compared susceptibility to the Sound-Induced Flash Illusion (SIFI) in retired professional rugby players compared to controls.

METHODS

Retired professional rugby players ((N = 58) and retired international rowers (N = 26) completed a self-report concussion history questionnaire and the SIFI task. Susceptibility to the SIFI (i.e., perceiving two flashes in response to one flash paired with two beeps) was assessed at three stimulus onset asynchronies (70 ms, 150 ms or 230 ms).Logistic mixed-effects regression modeling was implemented to evaluate how athlete grouping, previous concussion history and total number of years playing sport, impacted the susceptibility to the SIFI task. The statistical significance of a fixed effect of interest was determined by a likelihood ratio test.

RESULTS

Former rugby players had significantly more self-reported concussions than the rower group (p < 0.001). There was no impact of athlete grouping (i.e., retired professional rugby players and retired international rowers), years participation in elite sport or concussion history on performance in the SIFI.

CONCLUSION

A career in professional rugby, concussion history or number of years participating in professional rugby was not found to be predictive of performance on the SIFI task.

The Incidence, Cost, and Burden of Concussion in Women's Rugby League and Rugby Union: A Systematic Review and Pooled Analysis

BACKGROUND

The extent of concussion injury in the rugby codes for women is unclear.

OBJECTIVE

Our aim was to review all published studies reporting concussion injuries from match and training participation in rugby codes and report the pooled data estimates for rugby league and union concussion injury epidemiology.

METHODS

We conducted a systematic literature analysis of concussion in rugby league and rugby union for published studies from January 1990 to July 2021. Data from 16 studies meeting the inclusion criteria were extracted for women's concussion injuries and were subsequently pooled. Costs from Accident Compensation Corporation (ACC) data were attributed to the results to provide cost estimates.

RESULTS

The pooled analysis match injury incidence of women's concussion was higher for rugby league (10.3 per 1000 match hours) than rugby 15 s (2.8 per 1000 match hours) or rugby 7 s (8.9 per 1000 match hours). There was a fourfold difference in the pooled incidence of concussion in women's rugby league (risk ratio [RR] 4.53, 95% confidence interval [CI] 1.8-11.3]; p = 0.0001) when compared with rugby 15 s. There was also a ninefold higher risk of a concussion during match participation compared with training participation for women's rugby 15 s (RR 9.3, 95% CI 1.29-66.78; p = 0.0070). The total estimated costs for the concussions reported were NZ$1,235,101. For rugby 7 s, the pooled concussive injury burden was 33.2 days.

CONCLUSIONS

Our pooled analysis clarified the extent of concussion injury and the possible associated costs at several levels of the game for women's rugby codes. The pooled mean days lost because of concussions was 33 days. As this was considerably longer than the 7- to 10-day expected timeframe outlined in the Concussion in Sport Consensus statement, these guidelines need to be updated to include sex-specific differences.

Examining for Cavum Septum Pellucidum and Ventricular Enlargement in Retired Elite-Level Rugby League Players

Objective

A cavum septum pellucidum (CSP) has been reported as a visible brain anomaly in normal individuals as well in some former combat and collision sport athletes. The appearance of CSP with fenestrations and ventricular enlargement are considered associated features of the neuropathological diagnosis of chronic traumatic encephalopathy. The current study examined CSP anatomic features and lateral ventricle size in retired elite rugby league players and controls.

Methods

Forty-one retired rugby league players and 41 healthy community controls, similar in age and education, underwent structural MRI scans. CSP grade, CSP length, corpus callosum septal length, and Evans' ratio (for lateral ventricle size) were rated by two of the current study authors. All participants also self-reported concussion exposure histories, depressive symptoms, daytime sleepiness, and impulsivity. They completed a neuropsychological test battery assessing premorbid intellectual functioning, attention, processing speed, language, visuospatial skills, memory, and aspects of executive functioning.

Results

The two raters had high agreement for CSP grade (Cohen's κ = 0.80), CSP length [intraclass correlation (ICC) = 0.99], corpus callosum septal length (ICC = 0.73), the CSP/septal ratio (ICC = 0.99), and the Evans' ratio (ICC = 0.75). Twenty-five retired players (61.0%) had an abnormal CSP compared to 17 controls [41.5%; χ(1, 82)2 = 3.12, p = 0.08, odds ratio = 2.21]. The CSP/septal ratio was larger for retired players than for the controls. The Evans' ratio did not differ between the two groups. In the retired rugby league players (n = 41), those with normal (n = 16) and abnormal (n = 25) CSP grades did not differ across age, age of first exposure to collision sport, years of sport exposure, concussion history, or 23 clinical and cognitive variables.

Conclusion

This study revealed a difference in the size of the CSP between retired professional rugby league players and controls. There was no significant difference in the size of the ventricles between the two groups. There were no significant differences between those with vs. without an abnormal CSP on age of first exposure to rugby league, years of exposure to repetitive neurotrauma, number of lifetime concussions, depression, impulsivity, perceived cognitive decline, or on any neuropsychological test.

An Investigation into Helmet Use, Perceptions of Sports-Related Concussion, and Seeking Medical Care for Head Injury amongst Competitive Cyclists

The purpose of this study was to investigate competitive cyclists' helmet use, perceptions of sports-related concussion (SRC), and medical-care-seeking behaviors. A mixed-method approach was used with qualitative and quantitative data presented. The study comprised of a cross-sectional analysis of 405 competitive cyclists who completed an online survey. Results indicated that most participants believed a bicycle helmet protects against SRC (79.5%) and considerable numbers of participants would not seek medical care for potential head injury in scenarios where this would be recommended. It was also discovered that marketing of concussion reduction technology influences cyclists' helmet-purchasing behaviors. With the data presented, it is recommended that governing bodies in cycling need to develop educational resources to address gaps in knowledge regarding SRC amongst cyclists. We also suggest that more independent research on concussion reduction technologies in bicycle helmets is needed, with advertising supported by clear scientific evidence to avoid negatively influencing head injury management and reporting behaviors amongst cyclists.

An update on pathophysiology and treatment of sports-mediated brain injury

Traumatic brain injury (TBI) is a neurological disorder which represents a major health issue worldwide. It causes mortality and disability among all group ages, caused by external force, sports-related events or violence and road traffic accidents. In the USA, approximately one-third people die annually due to injury and 1.7 million people suffer from traumatic brain injury. Every year in India around 1.6 million individuals suffer from sustain brain injury with 200,000 deaths and approximately one million person needed recovery treatment at any stage of time. Sports-related head impact and trauma has become an extremely controversial public health and medico-legal problem that accounts for 20% of all brain injury (including concussion). It is difficult to reverse the primary injury but the secondary injury can be minimized by using proper pharmacological intervention during the initial hours of injury. This article highlights the pathophysiology and types of TBI along with treatment therapies. Till date, there is no single medication that can decrease the progression of the disease so that symptomatic treatment is given to the patient by determining proper pathology. Recently various herbal medicine therapies and traditional supplements have been developed for TBI. Nutritional supplementation and nutraceuticals have exposed potential in the treatment of TBI when used before and after TBI. The compiled data will enable the readers to know the pathophysiology as well as the allopathic and natural remedies to treat the TBI.

Potential of Soft-Shell Rugby Headgear to Mitigate Linear and Rotational Peak Accelerations

Rugby union is a popular sport played across the world. The physical contact inherent in the game means that players are at increased risk of concussive injury. In 2019, World Rugby created a new category of permitted headgear under Law 4 as a medical device. This established a pathway for headgear designed to reduce peak accelerations to be worn in matches. Investigations of the potential of soft-shelled protective headgear to reduce head impact accelerations have been mostly limited to the analysis of linear kinematics. However rotational head impact accelerations have long been implicated as far more injurious. The aim of this study, therefore, was to assess the linear and rotational acceleration reduction brought about by soft-shelled rugby headgear. A Hybrid III headform and neck were dropped onto a modular elastomer programmer impact surface, impacting at four different velocities (1.7–3.4 m/s) in five different impact orientations. Impact surface angles were 0°, 30°, and 45°. Peak linear and rotational accelerations, PLA and PRA respectively, were recorded. All headgear significantly reduced PLAs and PRAs when compared to a no headgear scenario. The new generation, headgear reduced all measures significantly more than the older generation of headgear. Impact locations offset from the center of mass of the headform resulted in the highest PRAs measured. As the impact surface angle increased, both PLAs and PRAs decreased. The study demonstrated that headgear tested lowered PLAs by up to 50%, and PRAs by up to 60% compared to the bare headform. Our data suggest that new generation headgear could make a difference on the field in reducing injurious impact accelerations in a collision.

Development of a Machine-Learning-Based Classifier for the Identification of Head and Body Impacts in Elite Level Australian Rules Football Players

Background: Exposure to thousands of head and body impacts during a career in contact and collision sports may contribute to current or later life issues related to brain health. Wearable technology enables the measurement of impact exposure. The validation of impact detection is required for accurate exposure monitoring. In this study, we present a method of automatic identification (classification) of head and body impacts using an instrumented mouthguard, video-verified impacts, and machine-learning algorithms.

Methods: Time series data were collected via the Nexus A9 mouthguard from 60 elite level men (mean age = 26.33; SD = 3.79) and four women (mean age = 25.50; SD = 5.91) from the Australian Rules Football players from eight clubs, participating in 119 games during the 2020 season. Ground truth data labeling on the captures used in this machine learning study was performed through the analysis of game footage by two expert video reviewers using SportCode and Catapult Vision. The visual labeling process occurred independently of the mouthguard time series data. True positive captures (captures where the reviewer directly observed contact between the mouthguard wearer and another player, the ball, or the ground) were defined as hits. Spectral and convolutional kernel based features were extracted from time series data. Performances of untuned classification algorithms from scikit-learn in addition to XGBoost were assessed to select the best performing baseline method for tuning.

Results: Based on performance, XGBoost was selected as the classifier algorithm for tuning. A total of 13,712 video verified captures were collected and used to train and validate the classifier. True positive detection ranged from 94.67% in the Test set to 100% in the hold out set. True negatives ranged from 95.65 to 96.83% in the test and rest sets, respectively.

Discussion and conclusion: This study suggests the potential for high performing impact classification models to be used for Australian Rules Football and highlights the importance of frequencies <150 Hz for the identification of these impacts.

An Evaluation of Omega-3 Status and Intake in Canadian Elite Rugby 7s Players

Background: EPA and DHA n-3 FA play crucial roles in both neurological and cardiovascular health and high dietary intakes along with supplementation suggest potential neuroprotection and concussion recovery support. Rugby athletes have a high risk of repetitive sub-concussive head impacts which may lead to long-term neurological deficits, but there is a lack of research looking into n-3 FA status in rugby players. We examined the dietary n-3 FA intake through a FFQ and n-3 FA status by measuring the percentage of n-3 FA and O3I in elite Canadian Rugby 7s players to show distribution across O3I risk zones; high risk, <4%; intermediate risk, 4 to 8%; and low risk, >8%. Methods: n-3 FA profile and dietary intake as per FFQ were collected at the beginning of the 2017–2018 Rugby 7s season in male (n = 19; 24.84 ± 2.32 years; 95.23 ± 6.93 kg) and female (n = 15; 23.45 ± 3.10 years; 71.21 ± 5.79 kg) athletes. Results: O3I averaged 4.54% ± 1.77, with female athlete scores slightly higher, and higher O3I scores in supplemented athletes (4.82% vs. 3.94%, p = 0.183), with a greater proportion of non-supplemented athletes in the high-risk category (45.5% vs. 39.1%). Dietary intake in non-supplemented athletes did not meet daily dietary recommendations for ALA or EPA + DHA compared to supplemented athletes. Conclusions: Overall, despite supplementation, O3I score remained in the high-risk category in a proportion of athletes who met recommended n-3 FA dietary intakes, and non-supplemented athletes had a higher proportion of O3I scores in the high-risk category, suggesting that dietary intake alone may not be enough and athletes may require additional dietary and n-3 FA supplementation to reduce neurological and cardiovascular risk.

Baseline concussion assessment performance of community-based senior rugby players: a cross-sectional study

OBJECTIVE

To report pre-season baseline concussion assessment performance among senior rugby players and explore associations between assessment performance and player demographics.

DESIGN

A cross-sectional study using the New Zealand Rugby Concussion Assessments (NZRCA), comprising symptom, cognitive and dynamic coordination assessments was conducted in the 2018-2019 season.

METHODS

Players' baseline assessments were characterised using descriptive statistics; effect sizes (ES) and t-tests were used to explore associations between player demographic characteristics and NZRCA performance.

RESULTS

A total of 733 players (11.4% female) aged between 16 and 52 years completed the NZRCA. The median (range) value for symptom severity, endorsed symptoms and "percentage normal" was respectively, 5 (0-40), 5 (0-21) and 90% (30-100%). A perfect standardised assessment of concussion score was achieved by one participant; seven achieved ≥27/30 for immediate recall, and 22 achieved a perfect delayed recall score. Most participants (n = 674, 92%) passed the tandem gait test. Associations between NZRCA performance and gender, concussion history, and Pasifika ethnicity were observed with effect sizes ranging from small (0.18) to large (0.70). Six hundred and twenty-three (85%) participants reported at least one symptom.

CONCLUSIONS

The results from this study could help support decision-making by clinicians, improving the management of concussions in the community setting.

Predictors and Correlates of Perceived Cognitive Decline in Retired Professional Rugby League Players

Objective: Rugby league is an international full-contact sport, with frequent concussive injuries. Participation in other full-contact sports such as American football has been considered to be a risk factor for neuropsychiatric sequelae later-in-life, but little research has addressed the mental and cognitive health of retired professional rugby league players. We examined predictors and correlates of perceived (self-reported) cognitive decline in retired National Rugby League (NRL) players. Methods: Participants were 133 retired male elite level rugby league players in Australia. Participants completed clinical interviews, neuropsychological testing, and self-report measures. The Informant Questionnaire on Cognitive Decline in the Elderly, self-report (IQCODE-Self), measured perceived cognitive decline. Results: The median age of the sample was 55.0 (M = 53.1, SD = 13.9, range = 30-89) and the median years of education completed was 12.0 (M = 11.9, SD = 2.6, range = 7-18). The retired players reported a median of 15.0 total lifetime concussions (M = 28.0, SD = 36.6, range = 0-200). The mean IQCODE-Self score was 3.2 (SD = 0.5; Range = 1.3-5.0); 10/133 (7.5%) and 38/133 (28.6%) scored above conservative and liberal cutoffs for cognitive decline on the IQCODE-Self, respectively. Perceived cognitive decline was positively correlated with current depressive symptoms, negatively correlated with years of professional sport exposure and resilience, and unrelated to objective cognition and number of self-reported concussions. A multiple regression model with perceived cognitive decline regressed on age, concussion history, professional rugby league exposure, depression, resilience, objective cognitive functioning, daytime sleepiness, and pain severity showed depression as the only significant predictor. Conclusion: This is the first large study examining subjectively experienced cognitive decline in retired professional rugby league players. Similar to studies from the general population and specialty clinics, no relationship was found between objective cognitive test performance and perceived cognitive decline. Depressive symptoms emerged as the strongest predictor of perceived cognitive decline, suggesting that subjective reports of worsening cognition in retired elite rugby league players might reflect psychological distress rather than current cognitive impairment.

Cannabis and Athletic Performance

Cannabis is widely used for both recreational and medicinal purposes on a global scale. There is accumulating interest in the use of cannabis and its constituents for athletic recovery, and in some instances, performance. Amidst speculation of potential beneficial applications, the effects of cannabis and its two most abundant constituents, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), remain largely un-investigated. The purpose of this review is to critically evaluate the literature describing the effects of whole cannabis, THC, and CBD, on athletic performance and recovery. While investigations of whole cannabis and THC have generally shown either null or detrimental effects on exercise performance in strength and aerobic-type activities, studies of sufficient rigor and validity to conclusively declare ergogenic or ergolytic potential in athletes are lacking. The ability of cannabis and THC to perturb cardiovascular homeostasis warrants further investigation regarding mechanisms by which performance may be affected across different exercise modalities and energetic demands. In contrast to cannabis and THC, CBD has largely been scrutinized for its potential to aid in recovery. The beneficial effects of CBD on sleep quality, pain, and mild traumatic brain injury may be of particular interest to certain athletes. However, research in each of these respective areas has yet to be thoroughly investigated in athletic populations. Elucidating the effects of whole cannabis, THC, and CBD is pertinent for both researchers and practitioners given the widespread use of these products, and their potential to interact with athletes' performance and recovery.

Age of First Exposure to Collision Sports Does Not Affect Patient Reported Outcomes in Women and Men Community Rugby Players

PURPOSE

This study aimed to determine the relationship between age of first exposure (AFE) to repetitive head impacts through contact/collision sports and patient-reported outcomes in community rugby players.

METHODS

We recruited community rugby players older than 18 yr with at least 1 yr of contact rugby participation to complete an online survey. Participants completed the Brief Symptom Inventory-18 (BSI-18), Short-Form Health Survey 12 (SF-12), and Satisfaction with Life Scale (SWLS) via Qualtrics. We used generalized linear models to examine the association between AFE (continuous) and patient-reported outcomes by sex, while controlling for cumulative years contact/collision sport history, age, and concussion history (yes/no). In addition, we used Mann-Whitney U tests to compare patient-reported outcomes between AFE <12 and AFE ≥12.

RESULTS

A total of 1037 rugby players (31.6 ± 11.3 yr (range, 18-74 yr), 59.1% men) participated in this study. Whether analyzed continuously or dichotomously at age 12 yr, younger AFE was not associated with worse patient-reported outcomes for either men or women. Positive concussion history was a significant predictor of worse BSI-18 subscores, SF-12 subscores, and SWLS in women and worse BSI-18 subscores in men. Cumulative contact/collision sport history was a significant predictor of better BSI-18 Depression and SF-12 (Mental Component Summary) subscores in men only. In men and women, older age was a significant predictor of better BSI-18 Depression, Anxiety, and GSI subscores; better SWLS (in men only); and better SF-12 Mental Component Summary, but worse SF-12 (Physical Component Summary).

CONCLUSIONS

Younger AFE to contact/collision sport is not associated with worse patient-reported outcomes in early adult rugby players. Concussion history was predictive of worse patient-reported outcomes.

Trends in match concussion incidence and return-to-play time in male professional Rugby Union: A 16-season prospective cohort study

AIM

To describe trends in the incidence of match concussions and time to return-to-play in professional rugby union.

METHODS

Match concussion incidence (injuries per 1000 player-match-hours) and time to return-to-play (mean and median days absence) were recorded in 3006 male professional rugby union players over 16 seasons (2002/03 - 2018/19).

RESULTS

From 2002/03 to 2009/10, incidence of concussions was stable at 4.3/1000 player-match-hours. From 2009/10 to 2018/19, there was an increase in concussion incidence, with the highest incidence in 2016/17 at 20.9/1000 player-match-hours (95% CI: 17.9-24.3). Annual prevalence of concussion also increased, suggesting more players were concussed rather than the same players sustaining more concussions. Before the introduction of standardized graduated return-to-play (GRTP) guidelines in 2011, 27% of players returned to play in <6 days. After the introduction of the GRTP, this decreased to 7%, with no players returning in <6 days after 2014/15. Between 2002/03 and 2018/19, incidence of all other injuries remained stable.

CONCLUSIONS

From 2009/10 onwards, the incidence of diagnosed concussions increased. Since the introduction of the GRTP, there has been a dramatic reduction in the number of players returning in <6 days.

The Neurological Consequences of Engaging in Australian Collision Sports

Collision sports are an integral part of Australian culture. The most common collision sports in Australia are Australian rules football, rugby union, and rugby league. Each of these sports often results in participants sustaining mild brain traumas, such as concussive and subconcussive injuries. However, the majority of previous studies and reviews pertaining to the neurological implications of sustaining mild brain traumas, while engaging in collision sports, have focused on those popular in North America and Europe. As part of this 2020 International Neurotrauma Symposium special issue, which highlights Australian neurotrauma research, this article will therefore review the burden of mild brain traumas in Australian collision sports athletes. Specifically, this review will first provide an overview of the consequences of mild brain trauma in Australian collision sports, followed by a summary of the previous studies that have investigated neurocognition, ocular motor function, neuroimaging, and fluid biomarkers, as well as neuropathological outcomes in Australian collision sports athletes. A review of the literature indicates that although Australians have contributed to the field, several knowledge gaps and limitations currently exist. These include important questions related to sex differences, the identification and implementation of blood and imaging biomarkers, the need for consistent study designs and common data elements, as well as more multi-modal studies. We conclude that although Australia has had an active history of investigating the neurological impact of collision sports participation, further research is clearly needed to better understand these consequences in Australian athletes and how they can be mitigated.

Incidence and Risk Factors in Concussion Events: A 5-Season Study in the French Top 14 Rugby Union Championship

BACKGROUND

Concussions are a source of major concern in rugby, and a limited number of studies have attempted to identify risk factors for these injuries.

PURPOSE

To investigate the incidence of match concussion and associated risk factors, including individual workload, anthropometric variables, playing position, and season phase, in elite rugby union players.

STUDY DESIGN

Case-control study; Level of evidence 3.

METHODS

All concussions and explanatory variables were collected for every match over 5 consecutive seasons (2014-2018) in 1334 professional players participating in the French Top 14 championship. Concussion risk was estimated using mixed effects Poisson regression.

RESULTS

Mean match concussion incidence equated to 10.4 (95% CI, 9.3-11.5) concussions for 1000 hours of game exposure. A peak was reached in the 2016-2017 season (13.7; 95% CI, 11.0-16.5). A greater risk was observed in the playoffs as compared with the first phase of the season (incidence rate ratio, 3.96; 95% CI, 2.10-7.35). In comparison with other positions, half-backs incurred the highest rate of concussion events (incidence, 16.1; 95% CI, 11.8-20.3). Irrespective of playing position, those with greater height and lower body mass reported a higher risk of concussions (P = .02), especially during tackling actions for lighter players (P = .01) and during other match events for taller players (P = .03). When adjusted for season phase, players who had accumulated a higher amount of playing time since the beginning of the season demonstrated a lower risk of concussion (P = .005).

CONCLUSION

Inter- and intraseasonal variations in concussion rates were observed. Within positional groups, lighter and taller players were more at risk, with the highest incidence generally observed in half-backs. Workload was measured by the number of matches played before a concussion event, and it appeared to have a protective rather than deleterious effect on concussion risk.