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dc.contributor.authorBesier, TF
dc.contributor.authorLloyd, DG
dc.contributor.authorAckland, TR
dc.date.accessioned2012-11-01
dc.date.accessioned2017-03-02T00:06:04Z
dc.date.available2014-10-10T00:59:54Z
dc.date.available2017-03-02T00:06:04Z
dc.date.issued2003
dc.identifier.issn0195-9131
dc.identifier.urihttp://hdl.handle.net/10072/63251
dc.description.abstractPurpose: The purpose of this article was to investigate the activation patterns of muscles surrounding the knee during preplanned (PP) and unanticipated (UN) running and cutting tasks, with respect to the external moments applied to the joint. It was hypothesized that activation strategies during PP tasks would correspond to the magnitude and direction of the external loads applied to the knee joint, and the muscle activation patterns would differ between PP and UN tasks. Methods: Eleven healthy male subjects performed a series of running and cutting tasks under PP and UN conditions. Activation from 10 knee muscles were determined using full-wave rectified, filtered, and normalized EMG calculated during a precontact phase and two epochs across the stance phase. Knee joint flexor and extensor muscle group ratios indicated the level of co-contraction. Individual muscles were also grouped into medial/lateral and internal/external rotation muscle groups, based upon their ability to counter externally applied varus/valgus and internal/external rotation joint loads, respectively. Results: Selective activation of medial/lateral and internal/external rotation muscles and co-contraction of flexors and extensors were used to stabilize the joint under PP conditions, whereas generalized co-contraction strategies were employed during the UN condition. Net muscle activation during the UN sidestepping tasks increased by 10–20%, compared with an approximately 100% increase in applied varus/valgus and internal/external rotation joint moments. Conclusion: In PP conditions, activation patterns appear to be selected to support the external loads experienced at the knee, e.g., medial muscles activated to resist applied valgus moments. Under UN conditions, there was no selective activation of muscles to counter the external knee load, with generalized co-contraction being the activation pattern adopted. These findings have implications for the etiology of noncontact knee ligament injuries.
dc.description.peerreviewedYes
dc.description.publicationstatusYes
dc.languageEnglish
dc.language.isoeng
dc.publisherWolters Kluwer LWW
dc.publisher.placeHagerstown MD
dc.publisher.urihttp://journals.lww.com/acsm-msse/Abstract/2003/01000/Muscle_Activation_Strategies_at_the_Knee_during.19.aspx
dc.relation.ispartofpagefrom119
dc.relation.ispartofpageto127
dc.relation.ispartofissue1
dc.relation.ispartofjournalMedicine and Science in Sports and Exercise
dc.relation.ispartofvolume35
dc.subject.fieldofresearchSports science and exercise
dc.subject.fieldofresearchBiomechanics
dc.subject.fieldofresearchSports medicine
dc.subject.fieldofresearchMedical physiology
dc.subject.fieldofresearchcode4207
dc.subject.fieldofresearchcode420701
dc.subject.fieldofresearchcode320225
dc.subject.fieldofresearchcode3208
dc.titleMuscle activation strategies at the knee during running and cutting manoeuvres
dc.typeJournal article
dc.type.descriptionC1 - Articles
dc.type.codec1x
gro.facultyGriffith Health Faculty
gro.date.issued2014-10-10T00:59:54Z
gro.hasfulltextNo Full Text
gro.griffith.authorLloyd, David


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