Diagnosed concussion is associated with increased risk for lower extremity injury in community rugby players

Clinical Measures Associated with Subsequent Injury after Adolescent Concussion: A Prospective Cohort Study

PURPOSE

This study aimed to examine associations between clinical measures (self-reported and clinician administered) and subsequent injury rates in the year after concussion return to play (RTP) among adolescent athletes.

METHODS

We performed a prospective, longitudinal study of adolescents ages 13-18 yr. Each participant was initially assessed within 21 d of concussion and again within 5 d of receiving RTP clearance from their physician. Participants completed self-report measures: the Pittsburgh Sleep Quality Index and Tampa Scale of Kinesiophobia, and clinician-administered measures: single- and dual-task tandem gait and reaction time (RT; simple and clinical) assessments. They then completed monthly surveys for a year after RTP, which assessed exposure to injury (sport participation) and subsequent injuries (musculoskeletal or concussions) sustained. We used Poisson regression models to calculate injury rate ratios with the number of subsequent injuries sustained as the outcome, adjusted for RTP clearance time and competitive exposures for each measure.

RESULTS

Forty-one participants were included (age = 15.5 ± 1.3 yr, 56% female, 9.6 ± 4.6 d postconcussion; 38.0 ± 31.5 d to RTP). A higher injury rate per athletic exposure was observed for simple RT ≥ 505 ms versus <505 ms (injury rate ratio = 2.96, 95% confidence interval = 1.41-6.60, P = 0.005). Injury rates did not significantly differ by Pittsburgh Sleep Quality Index or Tampa Scale of Kinesiophobia scores, single/dual-task tandem gait time, or clinical RT.

CONCLUSIONS

Simple RT may be one risk factor that is associated with higher rates of subsequent injury after adolescent concussion. A simple RT measure incorporated into a comprehensive concussion RTP assessment may identify some individuals at higher risk of subsequent injury in the year after concussion, although further research is needed to better understand this relationship.

Understanding of head injury assessment and return to play processes and associated factors in United States Major League Rugby players

OBJECTIVES

Evaluate professional rugby players' self-reported perceived understanding of the head injury assessment (HIA) and return to play (RTP) processes and determine factors related to understanding and trust pertaining to these processes.

METHODS

An electronic survey measured concepts of interest. A thematic analysis of player understanding was performed, and player statements were coded.

RESULTS

207 U.S. Major League Rugby (MLR) players participated (26.7 ± 3.4 years). HIA and RTP protocol understanding was not correlated with concussion history (p = 0.41). International rugby experience and trust regarding MLR support of the following protocols and opposing team medical staff practices varied in their relationship to HIA understanding. Trust that all MLR teams follow the same protocols was positively correlated with all HIA questions (ps < 0.03). No HIA questions were correlated with trust in their own team's medical staff. All trust questions were significantly correlated with RTP process understanding. Qualitative analysis identified four HIA- and RTP-related themes: education needs, staffing needs, HIA criticisms, and importance of player safety.

CONCLUSION

International playing experience and greater trust in the MLR and league stakeholders were associated with greater player understanding of the HIA and RTP protocols. These results provide insight into the importance of educating players on league-specific concussion protocols.

Diagnosed concussion is associated with increased risk for upper extremity injury in community rugby players in males only

OBJECTIVES

To cross-sectionally determine 1) the association between lifetime diagnosed concussion and upper extremity musculoskeletal injury (UE-MSI) amongst a novel cohort of community rugby union players and 2) the sex specific risk of UE-MSI given concussion history among these rugby players.

METHODS

1,037 (31.0% female, 31.6 + 11.3 years) rugby players completed an online survey to determine lifetime history of diagnosed concussion (yes; no) and UE-MSI (yes; no). A chi-squared test of association was performed between concussion and any UE-MSI; odds ratio risk was also determined. Analyses were repeated by sex (male; female) and with specific UE-MSI (e.g. sprains, broken bones, dislocations).

RESULTS

There was a significant association between concussion and any UE-MSI for this cohort (χ(1) = 10.802, p = 0.001, OR = 1.70 [95%CI: 1.23-2.32]). There was a significant association between concussion and any UE-MSI among males for (χ(1) = 13.612, p < 0.001, OR = 2.20 [95%CI: 1.4-3.3]) but not among females (χ(1) = 0.735, p = 0.391, OR = 1.20 [95%CI: 0.8-2.0]).

CONCLUSIONS

Community rugby players with a history of diagnosed concussion are at 1.7× increased odds for history of any UE-MSI compared to rugby players who are concussion naïve; sex specific analyses revealed only increased risk among males. Sports medicine professionals and rugby stakeholders should view concussions as a risk factor and utilize established injury prevention programs to help reduce future UE-MSI in athletes.

Factors Affecting Sport-Related Concussion Non-Disclosure in Women's Rugby-A Multi-Country Qualitative Analysis

Background and Objectives: Collision-sport athletes, such as rugby players, are at risk of sport-related concussion (SRC). Women are known to be at higher risk of SRC and may experience more severe and chronic symptomology than men. Knowledge of the factors that affect a player's disclosure of their concussive symptoms could help to inform strategies to improve compliance with reporting and management of head injuries. The aim of this study was to investigate the factors that may impact women rugby players' disclosure of a concussion. Methods: Twenty-eight adult (≥18 years of age) elite and semi-elite women rugby players from the UK and Ireland (n = 17) and the United States (n = 11) were interviewed on their playing background and SRC experience in women's rugby via one-on-one interviews (UK and Ireland) or an online questionnaire (US). Results: SRC data were analysed inductively using a thematic analysis approach to determine the potential reasons for SRC non-disclosure in women's rugby. Four main themes were identified which may influence a player's SRC non-disclosure: 1. women rugby players are self-managing SRC; 2. work-related concerns impact on SRC disclosure; 3. players and support staff lack knowledge on SRC management; and 4. poor internal and external communication affect the support players receive when injured. Conclusions: The findings were consistent across players from different countries. This research highlighted several factors that may impact on women rugby players' disclosure of SRC regardless of country of origin (UK, Ireland, or US) and access to concussion care. Coaches and management teams should be aware of these reasons, which may enhance how they discuss and manage concussion. There is a clear need for further education on concussion for players and support staff and for strategies to create environments where women can openly discuss their concussion concerns.

Baseline concussion assessment performance by sex in military service academy rugby players: findings from the CARE Consortium

BACKGROUND

Normative student-athlete concussion assessment data may not be appropriate for service academy members (SAMs), particularly rugby players, because of the uniqueness of their academic/military training environment. Having accurate baseline data for this population is important because of their high risk for concussion and frequent lack of assigned sports medicine professional. The primary purpose of this study was to characterise baseline performance on a concussion assessment battery, with secondary purpose to determine effect of sex and concussion history on these measures among SAM rugby players.

METHODS

601 rugby-playing SAMs (19.3±1.5 years, 37.9% female) completed baseline concussion assessments: the Sport Concussion Assessment Tool (SCAT) Symptom and Symptom Severity Checklist, Standard Assessment of Concussion (SAC) and a neuropsychological test (either ImPACT (Immediate Post Concussion Assessment and Cognitive Testing) or ANAM (Automated Neuropsychological Assessment Metrics)). Groups were compared using an independent samples t-test or Mann-Whitney U test. A 2 (sex) × 2 (concussion history) ANOVA was conducted to determine the effects of sex and concussion history on outcomes.

RESULTS

Women reported greater SCAT total symptoms (3.3 vs 2.8, p<0.001, r=0.143) and symptom severities (5.7 vs 4.3, p<0.001, r=0.139), and performed worse on ImPACT Visual Memory (79.3 vs 82.6, p=0.002, r=0.144) than men. Women performed better than men on SAC (28.0 vs 27.7, p=0.03, r=0.088), ImPACT Reaction Time Composite (0.59 vs 0.61, p=0.04, r=0.092) and ANAM Code Substitution Delayed (64.3 vs 61.5, p=0.04, d=0.433). Individuals with a history of concussion reported lower ImPACT Symptom Severity (2.6 vs 4.2, p=0.02, r=0.110). There was no interaction between concussion history and sex on outcomes.

CONCLUSIONS

These findings provide reference data for SAM rugby players on baseline assessments and to help in clinical decision-making when managing sports-related concussion in absence of baseline data.

NCAA football players are at higher risk of upper extremity injury after first-time concussion

BACKGROUND

Previous research has demonstrated that concussions increase the risk of subsequent lower extremity musculoskeletal injury in athletes. However, the risk of upper extremity injury in athletes' post-concussion is poorly understood.

METHODS

All concussed football players within a National Collegiate Athletic Association (NCAA) Division I conference athletic database were identified between 2017 and 2021. After exclusions, each athlete experiencing their first concussion was then retrospectively reviewed for upper extremity injuries in the year prior to their concussion and in the year beginning at 90 days after their concussion. All upper extremity injuries were identified and the odds ratio, 95% confidence interval, and statistical significance between groups were calculated in Microsoft Excel.

RESULTS

160 de-identified football players from a single conference who were first diagnosed with concussions in the seasons from 2017 through 2021 met inclusion criteria. In these athletes the odds of upper extremity injury in year following first diagnosed concussion were 2.36 times higher than in the year prior (95% CI 1.13-4.95, p = 0.02). Shoulder was the most common site of injury with 57.7% of injuries compared to 19.2% in the hand, 15.4% in the elbow, 7.7% in the forearm, and 0% in the wrist.

CONCLUSION

This study demonstrates that collegiate football players are at a 2.36 times greater risk of upper extremity injury in the year following their first diagnosed concussion compared to the year preceding it. The most common site of upper extremity injury after concussion was the shoulder.

LEVEL OF EVIDENCE

III.

Non-contact lower limb injuries in Rugby Union: A two-year pattern recognition analysis of injury risk factors

The cause of sport injuries are multifactorial and necessitate sophisticated statistical approaches for accurate identification of risk factors predisposing athletes to injury. Pattern recognition analyses have been adopted across sporting disciplines due to their ability to account for repeated measures and non-linear interactions of datasets, however there are limited examples of their use in injury risk prediction. This study incorporated two-years of rigorous monitoring of athletes with 1740 individual weekly data points across domains of training load, performance testing, musculoskeletal screening, and injury history parameters, to be one of the first to employ a pattern recognition approach to predict the risk factors of specific non-contact lower limb injuries in Rugby Union. Predictive models (injured vs. non-injured) were generated for non-contact lower limb, non-contact ankle, and severe non-contact injuries using Bayesian pattern recognition from a pool of 36 Senior Academy Rugby Union athletes. Predictors for non-contact lower limb injuries included dorsiflexion angle, adductor strength, and previous injury history (area under the receiver operating characteristic (ROC) = 0.70) Dorsiflexion angle parameters were also predictive of non-contact ankle injuries, along with slower sprint times, greater body mass, previous concussion, and previous ankle injury (ROC = 0.76). Predictors of severe non-contact lower limb injuries included greater differences in mean training load, slower sprint times, reduced hamstring and adductor strength, reduced dorsiflexion angle, greater perceived muscle soreness, and playing as a forward (ROC = 0.72). The identification of specific injury risk factors and useable thresholds for non-contact injury risk detection in sport holds great potential for coaches and medical staff to modify training prescriptions and inform injury prevention strategies, ultimately increasing player availability, a key indicator of team success.

Sport Type and Risk of Subsequent Injury in Collegiate Athletes Following Concussion: a LIMBIC MATARS Consortium Investigation

OBJECTIVE

To investigate the association between sport type (collision, contact, non-contact) and subsequent injury risk following concussion in collegiate athletes.

MATERIALS AND METHODS

This retrospective chart review of 248 collegiate athletes with diagnosed concussions (age: 20.0 ± 1.4 years; height: 179.6 ± 10.9 cm; mass: 79.0 ± 13.6 kg, 63% male) from NCAA athletic programs (n = 11) occurred between the 2015-2020 athletic seasons. Acute injuries that occurred within six months following concussion were evaluated. Subsequent injuries were grouped by lower extremity, upper extremity, trunk, or concussion. The independent variable was sport type: collision, contact, non-contact. A Cox proportional hazard model was used to assess the risk of subsequent injury between sport types.

RESULTS

Approximately 28% (70/248) of athletes sustained a subsequent acute injury within six months post-concussion. Collision sport athletes had a significantly higher risk of sustaining any injury (HR: 0.41, p < 0.001, 95% CI: 0.28, 0.62), lower extremity (HR: 0.55, p = 0.04, 95% CI: 0.32, 0.97), and upper extremity (HR: 0.41, p = 0.01, 95% CI: 0.20, 0.81) injuries following concussion. No differences between sport types were observed for other injuries.

CONCLUSION

Collision sport athletes had a higher rate of any subsequent injury, lower, and upper extremity injuries following concussion. Future research should focus on sport-specific secondary injury prevention efforts.

The 50 Most Cited Papers on Rugby since 2000 Reveal a Focus Primarily on Strength and Conditioning in Elite Male Players

We sought to conduct a bibliometric analysis and review of the most cited publications relating to rugby since 2000 in order to identify topics of interest and those that warrant further investigations. Clarivate Web of Science database was used to perform a literature search using the search term "rugby." The top 200 papers by citation count were extracted and reviewed for the inclusion criteria: all subjects were rugby players. The top 50 manuscripts were included for analysis of author, publication year, country of lead authors, institution, journal name and impact factor, topic, participant sex, and level of rugby. The total number of citations was 9,071 (average of 181.4 citations/article), with an average journal impact factor of 7.21; the top article was cited 407 times at the time of analysis. The most frequent publication was the Journal of Strength and Conditioning Research (26%), followed by the British Journal of Sports Medicine (20%) and the Journal of Sports Sciences (18%). Forty-eight (96%) of the manuscripts contained only male subjects, with 1 manuscript including females only and 1 manuscript containing mixed sexes. Thirty-three (66%) of the manuscripts focused on professional rugby players, with the next highest player group being mixed levels (10%). Twenty-eight (56%) concentrated on topics regarding strength and conditioning, 11 (22%) on injury, and 4 (8%) on physiology. Despite rugby being one of the most injurious sports and community players representing the largest component of the player pool, most of the top-cited rugby articles are cohort studies of professional male athletes focused on performance and strength and conditioning, noting the bias in research towards socially relevant topics that may not impact the majority of stakeholders and long-term health of rugby athletes. These findings highlight the need for further research among women and community athletes and on topics in injury prevention.

Associations Between Head Injury and Subsequent Risk of Falls: Results From the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND OBJECTIVES

Falls are a leading cause of head injury among older adults, but the risk of fall occurring after a head injury is less well-characterized. We sought to examine the association between head injury and subsequent risk of falls requiring hospital care among community-dwelling older adults.

METHODS

This analysis included 13,081 participants in the Atherosclerosis Risk in Communities Study enrolled in 1987-1989 and followed through 2019. The association of head injury (time-varying exposure, self-reported and/or ICD-9/10 code identified) with the risk of subsequent (occurring >1-month after head injury) falls requiring hospital care (ICD-9/10 code defined) was modeled using Cox proportional hazards regression. Secondary analyses included Fine and Gray proportional hazards regression to account for the competing risk of death, analysis of head injury frequency and severity, and formal testing for interaction by age, sex, and race. Models were adjusted for age, sex, race/center, education, military service, alcohol consumption, smoking, diabetes, hypertension, and psychotropic medication use.

RESULTS

The mean age of participants at baseline was 54 years, 58% were female, 28% were Black, and 14% had at least one head injury occurring over the study period. Over a median 23 years of follow-up, 29% of participants had a fall requiring medical care. In adjusted Cox proportional hazards models, individuals with head injury had 2.01 (95% CI 1.85-2.18) times the risk of falls compared with individuals without head injury. Accounting for the competing risk of mortality, individuals with head injury had 1.69 (95% CI 1.57-1.82) times the risk of falls compared with individuals without head injury. We observed stronger associations among men compared with women (men: hazard ratio [HR] = 2.60, 95% CI 2.25-3.00; women: HR = 1.80, 95% CI 1.63-1.99, p-interaction <0.001). We observed evidence of a dose-response association for head injury number and severity with fall risk (1 injury: HR = 1.68, 95% CI 1.53-1.84; 2+ injuries: HR = 2.37, 95% CI 1.92-2.94 and mild: HR = 1.97, 95% CI 1.78-2.18; moderate/severe/penetrating: HR = 2.50, 95% CI 2.06-3.02).

DISCUSSION

Among community-dwelling older adults followed over 30 years, head injury was associated with subsequent falls requiring medical care. We observed stronger associations among men and with increasing number and severity of head injuries. Whether older individuals with head injury might benefit from fall prevention measures should be a focus of future research.

Existence ≠ adherence. Exploring barriers to best practice in sports-related concussion return to play (SRC-RTP) in Irish amateur female sport

OBJECTIVES

Sports-Related Concussion (SRCs) are of relevant risk and burden for female athletes. The following study aimed to explore potential barriers to return to play (RTP) best practice in coaches of amateur female athletes, and medical professionals who may treat and manage SRCs in amateur female athletes.

DESIGN

Qualitative, semi-structured, virtual interviews following a critical analysis framework.

METHODS

Twenty-five coaches, allied healthcare professionals (AHPs), and general practitioners (GPs) were recruited and interviewed using a convenience snowball sample. Data were transcribed verbatim and thematically analysed.

RESULTS

Three themes were identified following reflexive thematic analysis; biopsychosocial norms, stakeholder inaction, and practitioner effectiveness. The findings identify numerous factors which limit the uptake of best practice guidelines as endorsed by Irish national governing bodies (NGBs). Education, training, and implementation of these guidelines are lacking, with sub-standard or non-existent medical support and poor general injury and/or SRC attitudes providing further resistance to these measures.

CONCLUSION

Existence of SRC-RTP protocols does not equal adherence to such. Greater efforts are required to translate knowledge provided by the 6th Concussion Consensus statement. NGBs, league and club administrators, and educators need to better support coaches, practitioners and athletes in the implementation of these protocols in amateur female sport.

Effects of contact/collision sport history on gait in early- to mid-adulthood

BACKGROUND

To determine the effect of contact/collision sport participation on measures of single-task (ST) and dual-task (DT) gait among early- to middle-aged adults.

METHODS

The study recruited 113 adults (34.88 ± 11.80 years, (mean ± SD); 53.0% female) representing 4 groups. Groups included (a) former non-contact/collision athletes and non-athletes who are not physically active (n = 28); (b) former non-contact/collision athletes who are physically active (n = 29); (c) former contact/collision sport athletes who participated in high-risk sports and are physically active (n = 29); and (d) former rugby players with prolonged repetitive head impact exposure history who are physically active (n = 27). Gait parameters were collected using inertial measurement units during ST and DT gait. DT cost was calculated for all gait parameters (double support, gait speed, and stride length). Groups were compared first using one-way analysis of covariance. Then a multiple regression was performed for participants in the high-risk sport athletes and repetitive head impact exposure athletes groups only to predict gait outcomes from contact/collision sport career duration.

RESULTS

There were no significant differences between groups on any ST, DT, or DT cost outcomes (p > 0.05). Contact/collision sport duration did not predict any ST, DT, or DT cost gait outcomes.

CONCLUSION

Years and history of contact/collision sport participation does not appear to negatively affect or predict neurobehavioral function in early- to mid-adulthood among physically active individuals.

Lower Extremity Musculoskeletal Injuries After Concussion in Collegiate Student-Athletes

BACKGROUND

An association has been identified between concussion and lower extremity musculoskeletal injury (LEMSKI) after return to sports participation. However, the collegiate student-athlete studies have relied on relatively small single-institution studies, which limits generalizability.

PURPOSE

To assess odds of, and time to, LEMSKI after concussion in US collegiate athletes, using the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP).

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Data from the NCAA ISP during the 2010-2011 through 2019-2020 athletic seasons were considered for analysis. Frequency distributions were examined for details related to the initial and subsequent injuries (injuries to bone, bursa, joint, ligament, muscle, or tendon). Multivariable logistic regression models and random-effects Poisson regression models examined odds of time loss (TL) and non-time loss (NTL) LEMSKI after concussion, as well as the time interval between initial concussion and subsequent LEMSKI in a single athletic season, or initial musculoskeletal injury (MSKI) and subsequent LEMSKI in a single athletic season. Analyses were performed separately for football and other sports.

RESULTS

A total of 31,556 initial injuries were recorded (football: 11,900; other sports: 19,656), which were followed by 0 or 1 injury in the same season. Overall, first injury type was not a significant predictor of subsequent LEMSKI, although certain contrasts yielded significant estimates. In football, the odds of NTL LEMSKI were higher after concussion than after upper extremity MSKI (UEMSKI; adjusted odds ratio [OR_Adj], 1.56; 95% CI, 1.06-2.31). In football, the odds of TL LEMSKI were lower after concussion than after UEMSKI (OR_Adj, 0.71; 95% CI, 0.51-0.99). No other significant effect estimates were observed for football or other sports.

CONCLUSION

First injury type, either concussion or upper extremity, was not associated with an elevated risk of LEMSKI. Specifically, the results of this study did not identify an elevated odds of LEMSKI after a concussion. However, the authors observed greater odds of NTL LEMSKI and lower odds of TL LEMSKI in football.

Anticipatory head control mechanisms in response to impact perturbations: An investigation of club rugby players with and without a history of concussion injury

OBJECTIVES

The primary objective of this study was to examine rugby players anticipatory and compensatory head control during predictable and unpredictable impact events.

METHODS

An observational cross-sectional study design. Fifty-one (17_healthy 34_concussion) male rugby players were exposed to external predictable and unpredictable impact perturbations at mid-chest level. Surface EMG of the upper-trapezius (UT), splenius-capitis (Spl) and sternocleidomastoid (Scm) was recorded and analysed across three temporal epochs typical for anticipatory and compensatory postural control. Synchronized sagittal head-kinematics were measured from high-speed video (500 fps). Nonparametric tests were used to examine within and between group effects.

RESULTS

Anticipatory head control was evident in predictable conditions, expressed by early posterior head displacement and activation of the Spl. Compared to unpredictable conditions, muscle amplitudes were significantly lower, as was head acceleration. Compared to Healthy, the Concussion athletes lacked early activation of the Spl, exhibited delayed anticipatory head adjustments and experienced higher head accelerations in predictable conditions.

CONCLUSION

Rugby players with concussion injuries have significant deficits in cervical spinal motor control. The concussed motor control strategy leads to higher inertial head accelerations and delayed anticipatory head displacements. Effects may persist for two or more years following injury, which may indicate re-injury vulnerability in these athletes.

Protect the Player, Protect the Game: Reflections from Ex-Professional Rugby Union Players on Law Changes, Protective Equipment, and Duty of Care in the Professional Game

The emphasis of this study was to interview ex-professional male rugby union players (n = 23, mean age 35.5 ± 4.7 years) and discuss concussion management during their careers. In this study, two major themes were identified: (1) the duty of care to professional rugby union players by medical personnel, coaching staff, and owners of professional clubs and (2) the use of protective equipment and law changes to enhance player safety. In total, twenty-three ex-professional rugby union players were interviewed, and the majority (61%) had represented their countries at international test-level rugby. These interviews highlighted the belief that medical teams should be objective, independent entities within a professional rugby club. Furthermore, medical teams should not be in a position of being pressurised by head coaches, members of the coaching team, or club owners regarding return-to-play (RTP) protocols specific to concussion. The interviewees believed that they were pressured by coaches or members of the coaching team to play with concussion or concussive symptoms and other physical injuries. The results indicated that they had manipulated concussion testing themselves or with assistance to pass standard concussion testing protocols. The interviewees indicated that club owners have a duty of care to players even in retirement due to the high incidence of physical and mental injuries endured as a professional rugby player. Most participants indicated that a reduction in match playing time and reducing the amount of time engaged in contact training (workload volume) may assist in reducing concussion incidence. The participants suggested that changes to the current laws of the game or the use of protective equipment did not mitigate against concussion risk in the game of rugby union. The main limitation to the study is that participants had retired in the past ten years, and conditions for players may have changed. This study has highlighted that additional efforts are required by professional clubs to ensure the highest duty of care is delivered to current players and recently retired players.

Machine Learning for Predicting Lower Extremity Muscle Strain in National Basketball Association Athletes

Background

In professional sports, injuries resulting in loss of playing time have serious implications for both the athlete and the organization. Efforts to quantify injury probability utilizing machine learning have been met with renewed interest, and the development of effective models has the potential to supplement the decision-making process of team physicians.

Purpose/Hypothesis

The purpose of this study was to (1) characterize the epidemiology of time-loss lower extremity muscle strains (LEMSs) in the National Basketball Association (NBA) from 1999 to 2019 and (2) determine the validity of a machine-learning model in predicting injury risk. It was hypothesized that time-loss LEMSs would be infrequent in this cohort and that a machine-learning model would outperform conventional methods in the prediction of injury risk.

Study Design

Case-control study; Level of evidence, 3.

Methods

Performance data and rates of the 4 major muscle strain injury types (hamstring, quadriceps, calf, and groin) were compiled from the 1999 to 2019 NBA seasons. Injuries included all publicly reported injuries that resulted in lost playing time. Models to predict the occurrence of a LEMS were generated using random forest, extreme gradient boosting (XGBoost), neural network, support vector machines, elastic net penalized logistic regression, and generalized logistic regression. Performance was compared utilizing discrimination, calibration, decision curve analysis, and the Brier score.

Results

A total of 736 LEMSs resulting in lost playing time occurred among 2103 athletes. Important variables for predicting LEMS included previous number of lower extremity injuries; age; recent history of injuries to the ankle, hamstring, or groin; and recent history of concussion as well as 3-point attempt rate and free throw attempt rate. The XGBoost machine achieved the best performance based on discrimination assessed via internal validation (area under the receiver operating characteristic curve, 0.840), calibration, and decision curve analysis.

Conclusion

Machine learning algorithms such as XGBoost outperformed logistic regression in the prediction of a LEMS that will result in lost time. Several variables increased the risk of LEMS, including a history of various lower extremity injuries, recent concussion, and total number of previous injuries.

Applied sports science and sports medicine in women's rugby: systematic scoping review and Delphi study to establish future research priorities

Objectives

In part 1, the objective was to undertake a systematic scoping review of applied sports science and sports medicine in women's rugby, and in part 2 to develop a consensus statement on future research priorities.

Design

In part 1, a systematic search of PubMed (MEDLINE), Scopus and SPORTDiscus (EBSCOhost) was undertaken from the earliest records to January 2021. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020, the PRISMA extension for Scoping Reviews, and the PRISMA extension protocols were followed. In part 2, 31 international experts in women's rugby (ie, elite players, sports scientists, medical clinicians, sports administrators) participated in a three-round Delphi consensus method. These experts reviewed the findings from part 1 and subsequently provided a list of priority research topics in women's rugby. Research topics were grouped into expert-based themes and expert-based subthemes via content analysis. Expert-based themes and expert-based subthemes were ranked from very low to very high research priority on a 1-5 Likert scale. Consensus was defined by ≥70% agreement. The median research priority agreement and IQR were calculated for each expert-based theme and subtheme.

Data sources

PubMed (MEDLINE), Scopus and SPORTDiscus (EBSCOhost).

Eligibility criteria for selecting studies

Studies were eligible for inclusion if they investigated applied sports science or sports medicine in women's rugby.

Results

In part 1, the systematic scoping review identified 123 studies, which were categorised into six sports science and sports medicine evidence-based themes: injury (n=48), physical performance (n=32), match characteristics (n=26), fatigue and recovery (n=6), nutrition (n=6), and psychology (n=5). In part 2, the Delphi method resulted in three expert-based themes achieving consensus on future research priority in women's rugby: injury (5.0 (1.0)), female health (4.0 (1.0)) and physical performance (4.0 (1.0)).

Summary/Conclusion

This two-part systematic scoping review and Delphi consensus is the first study to summarise the applied sports science and sports medicine evidence base in women's rugby and establish future research priorities. The summary tables from part 1 provide valuable reference information for researchers and practitioners. The three expert-based themes that achieved consensus in part 2 (injury, female health and physical performance) provide clear direction and guidance on future research priorities in women's rugby. The findings of this two-part study facilitate efficient and coordinated use of scientific resources towards high-priority research themes relevant to a wide range of stakeholders in women's rugby.

An 8-Week Neuromuscular Training Program After Concussion Reduces 1-Year Subsequent Injury Risk: A Randomized Clinical Trial

BACKGROUND

Existing data suggest that after concussion, athletes experience an increased risk of subsequent injury. Exploring methods that may reduce injury risk after successful postconcussion return to play may lead to new treatment approaches.

PURPOSE

To examine the efficacy of a neuromuscular training (NMT) intervention on acute sports-related time-loss injury over the subsequent year relative to standard of care.

STUDY DESIGN

Randomized clinical trial; Level of evidence, 1.

METHODS

A total of 27 youth athletes were assessed initially postconcussion (median, 7 days postconcussion; interquartile range [IQR], 5-10) and after return-to-play clearance (median, 40 days postconcussion; IQR, 15-52). After return-to-play clearance, they were randomly assigned to NMT intervention (n = 11; mean ± SD age, 14.7 ± 1.7 years; 36% female) or standard of care (n = 16; mean ± SD age, 15.3 ± 1.8 years; 44% female). The intervention (duration, 8 weeks; frequency, 2 times per week) included guided strength exercises with landing stabilization focus. Standard of care received no recommendations. For the subsequent year, athletes prospectively completed a monthly log of sports-related injuries and organized sports competitions.

RESULTS

During the first year after postconcussion return-to-play clearance, sports-related time-loss injuries were more common among standard of care relative to NMT intervention (75% [95% CI, 48%-93%] vs 36% [95% CI, 11%-69%]). After adjusting for age and sex, the hazard of subsequent injury in the standard-of-care group was 3.56 times (95% CI, 1.11-11.49; P = .0334) that of the NMT intervention group. Sports participation was similar between NMT intervention and standard of care during the year-long monitoring period (hours of organized sports per month; median, 12 [IQR, 2.6-32.1] vs 15.6 [IQR, 3.5-105.9]; P = .55). The age- and sex-adjusted incidence of injuries was 10.2 per 1000 competitive exposures (95% CI, 3.7-28.4) in the standard-of-care group as opposed to 3.4 per 1000 (95% CI, 0.9-13.4) in the NMT intervention group. After adjusting for age and sex, incidence of injuries was higher for standard of care vs NMT intervention (rate ratio, 2.96 [95% CI, 0.89-9.85]; P = .076).

CONCLUSION

Although preliminary, our findings suggest that an NMT intervention initiated after return-to-play clearance may significantly reduce sports-related time-loss injuries over the subsequent year.

REGISTRATION

NCT03917290 (ClinicalTrials.gov identifier).

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.