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dc.contributor.authorKian, Azadeh
dc.contributor.authorPizzolato, Claudio
dc.contributor.authorHalaki, Mark
dc.contributor.authorGinn, Karen
dc.contributor.authorLloyd, David
dc.contributor.authorReed, Darren
dc.contributor.authorAckland, David
dc.description.abstractStatic optimization is commonly employed in musculoskeletal modeling to estimate muscle and joint loading; however, the ability of this approach to predict antagonist muscle activity at the shoulder is poorly understood. Antagonist muscles, which contribute negatively to a net joint moment, are known to be important for maintaining glenohumeral joint stability. This study aimed to compare muscle and joint force predictions from a subject-specific neuromusculoskeletal model of the shoulder driven entirely by measured muscle electromyography (EMG) data with those from a musculoskeletal model employing static optimization. Four healthy adults performed six sub-maximal upper-limb contractions including shoulder abduction, adduction, flexion, extension, internal rotation and external rotation. EMG data were simultaneously measured from 16 shoulder muscles using surface and intramuscular electrodes, and joint motion evaluated using video motion analysis. Muscle and joint forces were calculated using both a calibrated EMG-driven neuromusculoskeletal modeling framework, and musculoskeletal model simulations that employed static optimization. The EMG-driven model predicted antagonistic muscle function for pectoralis major, latissimus dorsi and teres major during abduction and flexion; supraspinatus during adduction; middle deltoid during extension; and subscapularis, pectoralis major and latissimus dorsi during external rotation. In contrast, static optimization neural solutions showed little or no recruitment of these muscles, and preferentially activated agonistic prime movers with large moment arms. As a consequence, glenohumeral joint force calculations varied substantially between models. The findings suggest that static optimization may under-estimate the activity of muscle antagonists, and therefore, their contribution to glenohumeral joint stability.
dc.publisher.placeUnited Kingdom
dc.relation.ispartofpagefrom109348: 1
dc.relation.ispartofpageto109348: 31
dc.relation.ispartofjournalJournal of Biomechanics
dc.subject.fieldofresearchBiomedical Engineering
dc.subject.fieldofresearchHuman Movement and Sports Sciences
dc.subject.fieldofresearchMechanical Engineering
dc.subject.keywordsScience & Technology
dc.subject.keywordsLife Sciences & Biomedicine
dc.subject.keywordsEngineering, Biomedical
dc.titleStatic optimization underestimates antagonist muscle activity at the glenohumeral joint: a musculoskeletal modeling study
dc.typeJournal article
dc.type.descriptionC1 - Articles
dcterms.bibliographicCitationKian, A; Pizzolato, C; Halaki, M; Ginn, K; Lloyd, D; Reed, D; Ackland, D, Static optimization underestimates antagonist muscle activity at the glenohumeral joint: a musculoskeletal modeling study, Journal of Biomechanics, 2019, 97, pp. 109348: 1-109348: 31
gro.hasfulltextNo Full Text
gro.griffith.authorLloyd, David
gro.griffith.authorPizzolato, Claudio

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