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dc.contributor.authorRice, DA
dc.contributor.authorMcNair, PJ
dc.contributor.authorLewis, GN
dc.date.accessioned2013-11-14T20:51:01Z
dc.date.available2013-11-14T20:51:01Z
dc.date.copyright2011
dc.date.issued2013-11-15
dc.identifier.citationArthritis Research & Therapy 2011, 13:R151
dc.identifier.issn1478-6362
dc.identifier.urihttp://hdl.handle.net/10292/5872
dc.description.abstractIntroduction: A consequence of knee joint osteoarthritis (OA) is an inability to fully activate the quadriceps muscles, a problem termed arthrogenic muscle inhibition (AMI). AMI leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. The purpose of the present study was to determine whether g-loop dysfunction contributes to AMI in people with knee joint OA. Methods: Fifteen subjects with knee joint OA and 15 controls with no history of knee joint pathology participated in this study. Quadriceps and hamstrings peak isometric torque (Nm) and electromyography (EMG) amplitude were collected before and after 20 minutes of 50 Hz vibration applied to the infrapatellar tendon. Between-group differences in pre-vibration torque were analysed using a one-way analysis of covariance, with age, gender and body mass (kg) as the covariates. If the g-loop is intact, vibration should decrease torque and EMG levels in the target muscle; if dysfunctional, then torque and EMG levels should not change following vibration. One-sample t tests were thus undertaken to analyse whether percentage changes in torque and EMG differed from zero after vibration in each group. In addition, analyses of covariance were utilised to analyse between-group differences in the percentage changes in torque and EMG following vibration. Results: Pre-vibration quadriceps torque was significantly lower in the OA group compared with the control group (P = 0.005). Following tendon vibration, quadriceps torque (P < 0.001) and EMG amplitude (P ≤0.001) decreased significantly in the control group but did not change in the OA group (all P > 0.299). Hamstrings torque and EMG amplitude were unchanged in both groups (all P > 0.204). The vibration-induced changes in quadriceps torque and EMG were significantly different between the OA and control groups (all P < 0.011). No between-group differences were observed for the change in hamstrings torque or EMG (all P > 0.554). Conclusions: g-loop dysfunction may contribute to AMI in individuals with knee joint OA, partially explaining the marked quadriceps weakness and atrophy that is often observed in this population.
dc.languageeng
dc.publisherBioMed Central (BMC)
dc.relation.urihttp://dx.doi.org/10.1186/ar3467
dc.rights© 2011 Rice et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
dc.subjectAged
dc.subjectBiomechanics
dc.subjectElectromyography
dc.subjectFemale
dc.subjectHumans
dc.subjectKnee joint
dc.subjectMale
dc.subjectMiddle aged
dc.subjectMuscle weakness
dc.subjectOsteoarthritis, knee
dc.subjectQuadriceps muscle
dc.subjectTorque
dc.subjectVibration
dc.titleMechanisms of Quadriceps Muscle Weakness in Knee Joint Osteoarthritis: The Effects of Prolonged Vibration on Torque and Muscle Activation in Osteoarthritic and Healthy Control Subjects
dc.typeJournal Article
dc.rights.accessrightsOpenAccess
dc.identifier.doi10.1186/ar3467
aut.relation.issue5
aut.relation.startpageR151
aut.relation.volume13
pubs.elements-id67399


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