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

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

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

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

Time to expand the circle of care - General practitioners' experiences of managing concussion in the community.

New Zealand Rugby (NZR) implemented a concussion management pathway (CMP), aimed at improving management at community level. General Practitioners (GPs) played a large role in the design of this process. The objective of this study was to explore GPs' perceptions of barriers and facilitators of the CMP and rugby-related concussion management in the community. A descriptive qualitative approach using interviews and focus groups was employed. Four themes were derived: i) GPs' existing knowledge and confidence around concussion management; ii) Operational resources: time, remuneration and pathway guidance; iii) Standardising concussion care and iv) Expanding the circle of care - the need for multi-disciplinary healthcare team. These themes described how GP's concussion knowledge, and the efficiency and availability of operational resources affected their experience and ability to fulfil their tasks within the CMP. GPs found NZR's CMP especially valuable, as it provided guidance and structure. Expanding the role of other healthcare providers was seen as critical to reduce the burden on GPs, while also delivering a more holistic experience to improve clinical outcomes. Addressing the identified barriers and expanding the network of care will help to improve the ongoing development of NZR's CMP, while supporting continued engagement with all stakeholders.

Angle-Specific Isokinetic Shoulder Rotational Strength Can be Reliably Assessed in Collision and Contact Athletes.

An increased understanding of rotational strength as a potential prognostic factor for injury in contact and collision athletes may be important in planning return to sport. The aim of this study was to (1) determine the test-retest reliability of clinically relevant, angle-specific rotational and peak torque measurements in a cohort of uninjured collision and contact athletes; (2) develop a normal descriptive profile of angle-specific rotational torque measurements in the same cohort; and (3) examine the effects of direction and joint angle on shoulder rotational strength interlimb asymmetries. Twenty-three collision and contact athletes were recruited for the interday reliability substudy and 47 athletes were recruited for the remaining substudies. We used intraclass correlation coefficients with 95% confidence intervals to quantify interday reliability of all variables. We used a 2-way repeated-measures analysis of variance to analyze differences in absolute interlimb asymmetries. Interday reliability for the isokinetic strength variables was good to excellent (0.78-0.90) on the dominant side and moderate to good (0.63-0.86) on the nondominant side. Maximum angle-specific torque (as well as peak torque) can be measured reliably in internally and externally rotated positions. A normal profile of clinically relevant, angle-specific shoulder rotational torque measurements for collision and contact athletes has been established which provides a reference when assessing shoulder strength in this population.

Changes in the kinetics and kinematics of a reactive cut maneuver after successful athletic groin pain rehabilitation.

Athletic groin pain (AGP) is a chronic, painful condition which is prevalent in players of field sports that require rapid changes of direction. Following successful rehabilitation, systematic changes have been observed in the kinetics and kinematics of pre-planned change of direction maneuvers, providing insight into potential foci for rehabilitation monitoring and for the assessment of interventions. However, changing direction in field sports is often reactive rather than pre-planned, and it is not known whether such post-rehabilitation changes are seen in reactive maneuvers. We analyzed the stance phase kinetics and kinematics of a 90° reactive cutting maneuver in 35 AGP patients before and after a successful exercise intervention program. Following the intervention, transverse plane rotation of the pelvis toward the intended direction of travel increased, and the body center of mass was positioned more anteriorly relative to the center of pressure. Ankle dorsiflexion also increased, and participants demonstrated greater ankle plantar flexor internal moment and power during the second half of stance. These findings provide insight into mechanical variables of potential importance in AGP, as identified during a maneuver based on a common sporting task.

Baseline SCAT Performance in Men and Women: Comparison of Baseline Concussion Screens Between 6288 Elite Men's and 764 Women's Rugby Players.

OBJECTIVE: This study compared Sports Concussion Assessment Tool (SCAT) performance in elite male (6288 players) and female (764 players) rugby players, to determine whether reference limits used for the management and diagnosis of concussion should differ between sexes. DESIGN: Cross-sectional census sample. SETTING: Data from World Rugby's Head Injury Assessment management system were analyzed. This data set covers global professional rugby. PARTICIPANTS: All professional players who underwent baseline SCAT testing as part of World Rugby's concussion management requirement formed the study cohort. Ten thousand seven hundred fifty-four SCAT assessments from 6288 elite male rugby players and 1071 assessments from 764 elite female players were analyzed. INTERVENTION: Elite men and women rugby players are independent variables. MAIN OUTCOME MEASURES: Sports Concussion Assessment Tool performance, including symptoms endorsed, cognitive submode performance, and balance performance. RESULTS: Women endorsed significantly more symptoms, with greater symptom severity, than men (relative ratio 1.34, 95% confidence interval, 1.25-1.45 women vs men). Women outperformed men in cognitive submodes with the exception of immediate memory and delayed recall and made fewer balance errors than men during the modified Balance Error Scoring System. Clinical reference limits, defined as submode score achieved by the worst-performing 50% of the cohort, did not differ between men and women. CONCLUSIONS: Women and men perform differently during SCAT baseline testing, although differences are small and do not affect either the baseline or clinical reference limits that identify abnormal test results for most submodes. The greater endorsement of symptoms by women suggests increased risk of adverse concussion outcomes and highlights the importance of accurate evaluation of any symptom endorsement at baseline.

Biomechanical upper-extremity performance tests and isokinetic shoulder strength in collision and contact athletes.

The aim of this study was threefold (1) to assess the reliability of three upper-extremity performance tests: a countermovement push up, press jump and drop box land, performed on a set of dual-force plates (2) to examine whether there was an association between isokinetic dynamometry and the performance tests in a non-injured cohort of collision/contact athletes and (3) to establish a normal descriptive profile of the vertical ground reaction forces from the performance tests, in a cohort of contact/collision athletes. The study was split into two sub-sections; the inter-day reliability of three upper-extremity performance tests (n = 21) and a descriptive, correlation study investigating the relationship between isokinetic dynamometry and performance tests metrics (n = 39). We used intraclass correlation coefficients (absolute agreement, 2-way mixed-effects model) with 95% confidence intervals to quantify inter-day reliability of all variables. We used Pearson correlation coefficients to investigate associations between isokinetic strength and vertical ground reaction force asymmetry variables. Inter-day reliability was moderate-to-excellent for the upper-extremity performance tests (ICC 0.67-0.97). There was no statistically significant correlation between external and internal rotational peak torque and the variables of CPMU, PJ and BDL (r range = .02-.24).These upper-extremity tests are reliable for use with male contact/collision athletes.

Patellar and hamstring autografts are associated with different jump task loading asymmetries after ACL reconstruction.

After anterior cruciate ligament reconstruction (ACLR), there is a higher re-injury rate to the contralateral limb in athletes who undergo surgery using a bone-patellar-tendon-bone (BPTB) autograft than using a semitendinosus and gracilis hamstring tendon (HT) autograft. This may be influenced by differing lower-limb loading asymmetries present when athletes of each graft type return to play (RTP). The aim of this study was to compare bilateral countermovement jump (CMJ) phase-specific impulse asymmetries between athletes with BPTB and HT autografts 9 months post-ACLR, and to identify the relationship between impulse and isokinetic strength asymmetries. Male field sport athletes with a BPTB (n = 22) or HT (n = 22) autograft were tested approximately 9 months post-ACLR. An uninjured control group (n = 22) was also tested on a single occasion. Phase-specific bilateral absolute impulse asymmetries were calculated during the CMJ and compared between groups using Kruskal-Wallis and post-hoc testing. A linear regression model was used to assess the relationship between impulse asymmetries and isokinetic concentric knee extensor strength asymmetries. BPTB athletes demonstrated greater impulse asymmetries than HT athletes during the eccentric (P = 0.01) and concentric (P = 0.008) phases of the jump. Isokinetic strength asymmetry was a significant predictor of CMJ concentric impulse asymmetry in both BPTB (r2  = 0.39) and HT athletes (r2  = 0.18) but not eccentric impulse asymmetry in any group. The greater loading asymmetries demonstrated by BPTB than HT athletes 9 months after ACLR may contribute to the differing incidence rates of contralateral ACL injury. The findings suggest that graft-specific loading asymmetries should be targeted during rehabilitation prior to RTP.

International consensus definitions of video signs of concussion in professional sports.

BACKGROUND: The use of video to assist professional sporting bodies with the diagnosis of sport-related concussion (SRC) has been well established; however, there has been little consistency across sporting codes with regards to which video signs should be used, and the definitions of each of these signs. AIM: The aims of this study were to develop a consensus for the video signs considered to be most useful in the identification of a possible SRC and to develop a consensus definition for each of these video signs across the sporting codes. METHODS: A brief questionnaire was used to assess which video signs were considered to be most useful in the identification of a possible concussion. Consensus was defined as >90% agreement by respondents. Existing definitions of these video signs from individual sports were collated, and individual components of the definitions were assessed and ranked. A modified Delphi approach was then used to create a consensus definition for each of the video signs. RESULTS: Respondents representing seven sporting bodies (Australian Football League, Cricket Australia, Major League Baseball, NFL, NHL, National Rugby League, World Rugby) reached consensus on eight video signs of concussion. Thirteen representatives from the seven professional sports ranked the definition components. Consolidation and refinement of the video signs and their definitions resulted in consensus definitions for six video signs of possible concussion: lying motionless, motor incoordination, impact seizure, tonic posturing, no protective action-floppy and blank/vacant look. CONCLUSIONS: These video signs and definitions have reached international consensus, are indicated for use by professional sporting bodies and will form the basis for further collaborative research.

International study of video review of concussion in professional sports.

BACKGROUND: Video review has become an important tool in professional sporting codes to help sideline identification and management of players with a potential concussion. AIM: To assess current practices related to video review of concussion in professional sports internationally, and compare protocols and diagnostic criteria used to identify and manage potential concussions. METHODS: Current concussion management guidelines from professional national and international sporting codes were reviewed. Specific criteria and definitions of video signs associated with concussion were compared between codes. Rules and regulations adopted across the codes for processes around video review were also assessed. RESULTS: Six sports with specific diagnostic criteria and definitions for signs of concussion identified on video review participated in this study (Australian football, American football, world rugby, cricket, rugby league and ice hockey). Video signs common to all sports include lying motionless/loss of responsiveness and motor incoordination. The video signs considered by the majority of sports as most predictive of a diagnosis of concussion include motor incoordination, impact seizure, tonic posturing and lying motionless. Regulatory requirements, sideline availability of video, medical expertise of video reviewers and use of spotters differ across sports and geographical boundaries. By and large, these differences reflect a pragmatic approach from each sport, with limited underlying research and development of the video review process in some instances. CONCLUSIONS: The use of video analysis in assisting medical staff with the diagnosis or identification of potential concussion is well established across different sports internationally. The diagnostic criteria used and the expertise of the video review personnel are not clearly established, and research efforts would benefit from a collaborative harmonisation across sporting codes.

Clinical and biomechanical outcomes of rehabilitation targeting intersegmental control in athletic groin pain: prospective cohort of 205 patients.

BACKGROUND: Clinical assessments and rehabilitation in athletic groin pain (AGP) have focused on specific anatomical structures and uniplanar impairments rather than whole body movement. OBJECTIVE: To examine the effectiveness of rehabilitation that targeted intersegmental control in patients with AGP and to investigate post rehabilitation changes in cutting biomechanics. METHODS: Two hundred and five patients with AGP were rehabilitated focusing on clinical assessment of intersegmental control, linear running and change of direction mechanics in this prospective case series. Hip and Groin Outcome Score (HAGOS) was the primary outcome measure. Secondary measures included pain-free return to play rates and times, pain provocation on squeeze tests and three-dimensional (3D) biomechanical analysis during a 110° cutting manoeuvre. RESULTS: Following rehabilitation, patients demonstrated clinically relevant improvements in HAGOS scores (effect size (ES): 0.6-1.7). 73% of patients returned to play pain-free at a mean of 9.9 weeks (±3.5). Squeeze test values also improved (ES: 0.49-0.68). Repeat 3D analysis of the cutting movement demonstrated reductions in ipsilateral trunk side flexion (ES: 0.79) and increased pelvic rotation in the direction of travel (ES: 0.76). Changes to variables associated with improved cutting performance: greater centre of mass translation in the direction of travel relative to centre of pressure (ES: 0.4), reduced knee flexion angle (ES: 0.3) and increased ankle plantar flexor moment (ES: 0.48) were also noted. CONCLUSIONS: Rehabilitation focused on intersegmental control was associated with improved HAGOS scores, high rates of pain-free return to sporting participation and biomechanical changes associated with improved cutting performance across a range of anatomical diagnoses seen in AGP.

Implementation of the 2017 Berlin Concussion in Sport Group Consensus Statement in contact and collision sports: a joint position statement from 11 national and international sports organisations.

The 2017 Berlin Concussion in Sport Group Consensus Statement provides a global summary of best practice in concussion prevention, diagnosis and management, underpinned by systematic reviews and expert consensus. Due to their different settings and rules, individual sports need to adapt concussion guidelines according to their specific regulatory environment. At the same time, consistent application of the Berlin Consensus Statement's themes across sporting codes is likely to facilitate superior and uniform diagnosis and management, improve concussion education and highlight collaborative research opportunities. This document summarises the approaches discussed by medical representatives from the governing bodies of 10 different contact and collision sports in Dublin, Ireland in July 2017. Those sports are: American football, Australian football, basketball, cricket, equestrian sports, football/soccer, ice hockey, rugby league, rugby union and skiing. This document had been endorsed by 11 sport governing bodies/national federations at the time of being published.

The Number of Trials Required to Obtain a Representative Movement Pattern During a Hurdle Hop Exercise.

When reporting a subject's mean movement pattern, it is important to ensure that reported values are representative of the subject's typical movement. While previous studies have used the mean of 3 trials, scientific justification of this number is lacking. One approach is to determine statistically how many trials are required to achieve a representative mean. This study compared 4 methods of calculating the number of trials required in a hopping movement to achieve a representative mean. Fifteen males completed 15 trials of a lateral hurdle hop. Range of motion at the trunk, pelvis, hip, knee, and ankle, in addition to peak moments for the latter 3 joints were examined. The number of trials required was computed using a peak intraclass correlation coefficient method, sequential analysis with a bandwidth of acceptable variance in the mean, and a novel method based on the standard error of measurement (SEMind). The number of trials required across all variables ranged from 2 to 12 depending on method, joint, and anatomical plane. The authors advocate the SEMind method as it demonstrated fewer limitations than the other methods. Using the SEMind, the required number of trials for a representative mean during the lateral hurdle hop is 6.

Can a Single-Leg Squat Provide Insight Into Movement Control and Loading During Dynamic Sporting Actions in Patients With Athletic Groin Pain?

CONTEXT: Chronic athletic groin pain (AGP) is common in field sports and has been associated with abnormal movement control and loading of the hip and pelvis during play. A single-leg squat (SLS) is commonly used by clinicians to assess movement control, but whether it can provide insight into control during more dynamic sporting movements in AGP patients is unclear. OBJECTIVE: To determine the relationships between biomechanical measures in an SLS and the same measures in a single-leg drop landing, single-leg hurdle hop, and a cutting maneuver in AGP patients. DESIGN: Cross-sectional study. SETTING: Biomechanics laboratory. PATIENTS: 40 recreational field-sports players diagnosed with AGP. INTERVENTION: A biomechanical analysis of each individual's SLS, drop landing, hurdle hop, and cut was undertaken. MAIN OUTCOME MEASURES: Hip, knee, and pelvis angular displacement and hip and knee peak moments. Pearson product-moment correlations were used to examine relationships between SLS measures and equivalent measures in the other movements. RESULTS: There were no significant correlations between any hip or pelvis measure in the SLS with the same measures in the drop landing, hurdle hop, or cut (r = .03-.43, P > .05). Knee frontal- and transverse-plane angular displacement were related in the SLS and drop landing only, while knee moments were related in the SLS, drop-landing, and hurdle hop (r = .50-.67, P < .05). CONCLUSION: For AGP patients, an SLS did not provide meaningful insight into hip and pelvis control or loading during sporting movements that are associated with injury development. The usefulness of an SLS test in the assessment of movement control and loading in AGP patients is thus limited. The SLS provided moderate insight into knee control while landing and therefore may be of use in the examination of knee-injury risk.

Isokinetic muscle strength and readiness to return to sport following anterior cruciate ligament reconstruction: is there an association? A systematic review and a protocol recommendation.

INTRODUCTION: Following anterior cruciate ligament reconstruction (ACLR), strength is a key variable in regaining full function of the knee. Isokinetic strength is commonly used as part of the return to sport (RTS) criteria. AIM: We systematically reviewed the isokinetic strength evaluation protocols that are currently being used following ACLR. A secondary aim was to suggest an isokinetic protocol that could meet RTS criteria. METHOD: Articles were searched using ScienceDirect, PubMed and Sage Journals Online, combined with cross-checked reference lists of the publications. Protocol data and outcome measurements and RTS criteria were extracted from each article included in the review. RESULTS: 39 studies met the inclusion criteria and reported their isokinetic strength evaluation protocol following ACLR. The variables that were most commonly used were concentric/concentric mode of contraction (31 studies), angular velocity of 60°/s (29 studies), 3-5 repetitions (24 studies), range of motion of 0-90° (6 studies), and using gravity correction (9 studies). 8 studies reported strength limb symmetry index scores as part of their RTS criteria. CONCLUSIONS: There was no standardised isokinetic protocol following ACLR; isokinetic strength measures have not been validated as useful predictors of successful RTS. We propose a standard protocol to allow consistency of testing and accurate comparison of future research.