Does Lower-extremity Symmetry Matter for Anterior Cruciate Ligament Injury Risk in Male Rugby Union Athletes?

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aut.embargoNoen_NZ
aut.thirdpc.containsNoen_NZ
aut.thirdpc.permissionNoen_NZ
aut.thirdpc.removedNoen_NZ
dc.contributor.advisorBrughelli, Matt
dc.contributor.advisorHume, Patria A
dc.contributor.advisorBesier, Thor F
dc.contributor.authorBrown, Scott Randall
dc.date.accessioned2016-11-10T00:48:11Z
dc.date.available2016-11-10T00:48:11Z
dc.date.copyright2016
dc.date.created2016
dc.date.issued2016
dc.date.updated2016-11-09T23:40:36Z
dc.description.abstractRugby injuries are frequent and often severe. Injury to the anterior cruciate ligament (ACL) is devastating and can cause serious hardship. Differences between an athlete’s two legs, also known as an asymmetry, can increase injury risk. The question of interest in this thesis is does lower-extremity symmetry matter for ACL injury risk in male rugby union athletes. A review of the literature describing the aetiology and mechanisms of ACL injuries was performed in conjunction with a pilot investigation analysing rugby match footage to support the rationale of the thesis of investigating the sidestep manoeuvre in rugby. An in-depth systematic review and meta-analysis of knee mechanics during sidestepping concluded that weight acceptance is the most important phase to examine abduction moments of the knee when assessing ACL injury risk. A theoretical ACL injury model was conceived from our examination of the sidestep manoeuvre in rugby and contained elements of strength, balance and sprint kinetics. Laboratory-based practical assessment tools within our theoretical model were used to evaluate thirty male academy-level rugby athletes. The preferred legs were stronger (ES = 0.21 – 0.37), had better balance (ES = 0.63 – 1.0), produced greater sprint kinetics (ES = 0.32 – 0.67) and experienced a smaller knee abduction moment, a more flexed knee, less trunk lateral flexion and less distance between the centre-of-mass and the ankle-joint-centre while sidestepping (ES = -0.26 – -0.97) compared to the non-preferred legs. Forwards were stronger (ES = 0.50 – 0.66), had worse balance with larger asymmetries (ES = -0.66 – -1.8) and produced greater sprint kinetics with larger asymmetries (ES = 0.74 – 0.81) compared to backs. A hierarchical multiple regression was used to examine the contribution of each leg in determining increased knee abduction moments during sidestepping. While single-leg balance did not contribute to increased ACL injury risk (Ŕ² = < 1 – 4%), lower-extremity strength and sprint kinetics did (Ŕ² = < 1 – 31%). The preferred (Ŕ² = 41%) and non-preferred (Ŕ² = 8%) legs independently contribute to increased ACL injury risk with unique distributions of strength and sprint kinetics, however these contributions all appear linked with posterior-chain strength. In summary, criterion and practical laboratory-based assessment tools to measure and assess ACL injury risk factors in rugby athletes were identified in this thesis. Assessment tools were used to quantify the differences in strength, balance, sprint kinetics and three-dimensional sidestepping mechanics between the preferred and non-preferred legs and between forwards and backs in amateur academy-level male rugby athletes. Normative values, symmetry angle scores and a discussion of assessment components and training recommendations were provided. A new model and framework for assessing ACL injury risk were outlined to guide the progression of ACL injury prevention strategies in rugby athletes.en_NZ
dc.identifier.urihttps://hdl.handle.net/10292/10144
dc.language.isoenen_NZ
dc.publisherAuckland University of Technology
dc.rights.accessrightsOpenAccess
dc.subjectBiomechanicsen_NZ
dc.subjectACLen_NZ
dc.subjectSidestepen_NZ
dc.subjectIsokineticen_NZ
dc.subjectBalanceen_NZ
dc.subjectSprinten_NZ
dc.subjectStrengthen_NZ
dc.subjectDynamicen_NZ
dc.subjectKineticen_NZ
dc.subjectKinematicen_NZ
dc.subjectLeg preferenceen_NZ
dc.subjectAsymmetryen_NZ
dc.subjectPositionen_NZ
dc.subjectProfileen_NZ
dc.subjectKneeen_NZ
dc.subjectPreventionen_NZ
dc.subjectIndividualiseen_NZ
dc.subjectManoeuvreen_NZ
dc.subjectAssessmenten_NZ
dc.subjectJointen_NZ
dc.subjectLoadsen_NZ
dc.subjectMulti-componenten_NZ
dc.subjectHipen_NZ
dc.subjectTrainingen_NZ
dc.subjectPerformanceen_NZ
dc.subjectReturn-to-sporten_NZ
dc.titleDoes Lower-extremity Symmetry Matter for Anterior Cruciate Ligament Injury Risk in Male Rugby Union Athletes?en_NZ
dc.typeThesis
thesis.degree.grantorAuckland University of Technology
thesis.degree.levelDoctoral Theses
thesis.degree.nameDoctor of Philosophyen_NZ
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