Contact Role and Tackle Characteristics Shape Head Acceleration Exposure in Male Community Rugby: A Cohort Study Utilising Instrumented Mouthguards

Contact Role and Tackle Characteristics Shape Head Acceleration Exposure in Male Community Rugby: A Cohort Study Utilising Instrumented Mouthguards | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Contact Role and Tackle Characteristics Shape Head Acceleration Exposure in Male Community Rugby: A Cohort Study Utilising Instrumented Mouthguards Melanie Bussey, Danielle Salmon, Janelle Romanchuk, Darryl Tong, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7567286/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: Rugby Union has attracted increased scrutiny due to concerns over head acceleration events (HAEs), particularly regarding their frequency, severity, and potential long-term health implications. While substantial efforts by governing bodies have focused on reducing head impact risks through education, regulatory changes, and the introduction of instrumented mouthguards (iMGs), limited data exist for the community rugby context, especially across different age grades and playing positions. Objective: To quantify HAE across playing positions, age grades, and contact phases in community rugby, and to identify match scenarios associated with high-magnitude head loading. Methods: A prospective observational cohort study included 259 male players across U13, U15, U19, and Premier senior men’s grades. Players were fitted with iMGs, and match play was video recorded for verification. HAEs were identified from iMG-triggered acceleration events (SAEs) >5g and coded for match context, player position, and contact event characteristics. Statistical models evaluated differences in HAE frequency, incidence rates, and head kinematics (Peak Linear Acceleration [PLA], Peak Angular Acceleration [PAA], Rotational Velocity Change Index [RVCI]) across grades, positions, and contact scenarios. Results: A total of 7358 HAEs were verified from 8593 SAEs across 72 matches. Tackles and rucks accounted for ~60% of all HAEs. High tackles significantly increased head loading in ball carriers (PLA: +4.16 g, p = 0.02; PAA: +443 rad/s², p = 0.002; RVCI: +1.87 rad/s, p = 0.04), while low tackles elevated head loading in tacklers (PLA: +4.9 g, p = 0.004). Upright tacklers were more likely to produce high tackles (p < 0.001) and head-to-head contacts (p = 0.019). U13 ball carriers showed higher rotational loading than tacklers (RVCI: +5.01 rad/s, p = 0.008), likely reflecting frequent secondary mechanisms such as head-to-ground and body-to-ground. Defensive rucks carried greater HAE risk than attacking rucks (all p < 0.05), particularly for U19 jacklers (IRR = 2.27, p < 0.0001). Conclusions: Tackles and rucks are primary sources of HAEs, with risk shaped by posture, tackle height, and player role. Lower tackle heights reduce ball carrier load but increase tackler exposure, indicating a potential safety trade-off. Younger players, particularly U13s, were more susceptible to secondary impacts (e.g., head-to-ground), potentially due to limited task-specific experience and underdeveloped control during the tackled phase. Position- and age-specific strategies may be required to optimise safety and reduce HAE risk across all levels of community rugby. Sports Medicine and Kinesiology head impact rugby instrumented mouthguards concussion biomechanics Full Text Additional Declarations The authors declare potential competing interests as follows: This study builds upon the foundation of our ongoing research under the Otago Rugby Community Head Impact Detection (ORCHID) study series, which focuses on understanding the biomechanics and contextual risks of head acceleration events (HAEs) in men’s and women’s community rugby. Funding: World Rugby funded this project. Competing interests: MDB has received research funding from World Rugby. JR is currently employed part time by New Zealand Rugby as a Concussion Scientist and is enrolled as a PhD candidate at the University of Otago. RT serves as a consultant for World Rugby. DS was employed by New Zealand Rugby at the time of the study, received research funding from World Rugby, and is currently employed by the International Rugby Players Association. EF is the Chief Medical Officer for World Rugby. BN is currently employed by Prevent Biometrics as the Director of Applied Science and Integration, and was a research assistant at the University of Otago during the time of the study. While several authors hold roles within professional rugby organisations, these are disclosed in the interest of transparency. No author received direct compensation for the conduct or reporting of this study. The authors affirm that these affiliations did not influence the study design, data interpretation, or manuscript preparation. All other authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7567286","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":512118325,"identity":"004084de-8187-439a-9b96-2694b207ce3a","order_by":0,"name":"Melanie 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JR is currently employed part time by New Zealand Rugby as a Concussion Scientist and is enrolled as a PhD candidate at the University of Otago. RT serves as a consultant for World Rugby. DS was employed by New Zealand Rugby at the time of the study, received research funding from World Rugby, and is currently employed by the International Rugby Players Association. EF is the Chief Medical Officer for World Rugby. BN is currently employed by Prevent Biometrics as the Director of Applied Science and Integration, and was a research assistant at the University of Otago during the time of the study.\nWhile several authors hold roles within professional rugby organisations, these are disclosed in the interest of transparency. No author received direct compensation for the conduct or reporting of this study. The authors affirm that these affiliations did not influence the study design, data interpretation, or manuscript preparation.\nAll other authors declare no competing interests.\n","formattedTitle":"\u003cp\u003e\u003cem\u003eContact Role and Tackle Characteristics Shape Head Acceleration Exposure in Male Community Rugby: A Cohort Study Utilising Instrumented Mouthguards\u003c/em\u003e\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"University of Otago","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"head impact, rugby, instrumented mouthguards, concussion, biomechanics","lastPublishedDoi":"10.21203/rs.3.rs-7567286/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7567286/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRugby Union has attracted increased scrutiny due to concerns over head acceleration events (HAEs), particularly regarding their frequency, severity, and potential long-term health implications. While substantial efforts by governing bodies have focused on reducing head impact risks through education, regulatory changes, and the introduction of instrumented mouthguards (iMGs), limited data exist for the community rugby context, especially across different age grades and playing positions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObjective:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo quantify HAE across playing positions, age grades, and contact phases in community rugby, and to identify match scenarios associated with high-magnitude head loading.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA prospective observational cohort study included 259 male players across U13, U15, U19, and Premier senior men’s grades. Players were fitted with iMGs, and match play was video recorded for verification. HAEs were identified from iMG-triggered acceleration events (SAEs) \u0026gt;5g and coded for match context, player position, and contact event characteristics. Statistical models evaluated differences in HAE frequency, incidence rates, and head kinematics (Peak Linear Acceleration [PLA], Peak Angular Acceleration [PAA], Rotational Velocity Change Index [RVCI]) across grades, positions, and contact scenarios.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 7358 HAEs were verified from 8593 SAEs across 72 matches. Tackles and rucks accounted for ~60% of all HAEs. High tackles significantly increased head loading in ball carriers (PLA: +4.16 g, p = 0.02; PAA: +443 rad/s², p = 0.002; RVCI: +1.87 rad/s, p = 0.04), while low tackles elevated head loading in tacklers (PLA: +4.9 g, p = 0.004). Upright tacklers were more likely to produce high tackles (p \u0026lt; 0.001) and head-to-head contacts (p = 0.019). U13 ball carriers showed higher rotational loading than tacklers (RVCI: +5.01 rad/s, p = 0.008), likely reflecting frequent secondary mechanisms such as head-to-ground and body-to-ground. Defensive rucks carried greater HAE risk than attacking rucks (all p \u0026lt; 0.05), particularly for U19 jacklers (IRR = 2.27, p \u0026lt; 0.0001).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003eTackles and rucks are primary sources of HAEs, with risk shaped by posture, tackle height, and player role. Lower tackle heights reduce ball carrier load but increase tackler exposure, indicating a potential safety trade-off. Younger players, particularly U13s, were more susceptible to secondary impacts (e.g., head-to-ground), potentially due to limited task-specific experience and underdeveloped control during the tackled phase. Position- and age-specific strategies may be required to optimise safety and reduce HAE risk across all levels of community rugby.\u003c/p\u003e","manuscriptTitle":"Contact Role and Tackle Characteristics Shape Head Acceleration Exposure in Male Community Rugby: A Cohort Study Utilising Instrumented Mouthguards","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-10 05:00:07","doi":"10.21203/rs.3.rs-7567286/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f042ffb6-b5f4-4f9d-a9bf-568927ee6db1","owner":[],"postedDate":"September 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":54394624,"name":"Sports Medicine and Kinesiology"}],"tags":[],"updatedAt":"2025-09-10T05:00:07+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-10 05:00:07","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7567286","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7567286","identity":"rs-7567286","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}