title: Viscoelastic properties of the human sternocleidomastoideus muscle of aged women in relaxation.
abstract: Improving the numerical models of the head and neck complex requires understanding the mechanical properties of the muscles; however, most of the data in existing literature have been obtained from studies on animal muscles. Muscle is hyper-elastic, but also viscoelastic. The hyper-elastic behaviour of the human sternocleidomastoideus muscle has been previously studied. The aim of this study is to propose a characterization of the viscoelastic properties of the same human muscle in relaxation. Ten muscles were tested in vitro. The viscoelastic behaviour was modelled with a generalized Maxwell's model studied at the first and second order, using an inverse approach with a subject-specific, finite-element model of each muscle. Based on these models, relaxation times τ (first order: 103s; second order: 18s and 395s) and ratio moduli γ (first order: 0.33; second order: 0.20 and 0.19) were identified. The first-order model provided a good estimate of the relaxation curve (R(2): 0.82), but the second-order model was more representative of the experimental response (R(2): 0.97). Our results provide evidence that the viscoelastic behaviour of the human sternocleidomastoideus muscle can be described using a second-order Maxwell's model and that - combined with the previously identified hyper-elastic properties - the response of the muscle in tension and relaxation is fully characterized.
authors.affiliation: Arts et Metiers ParisTech, LBM, 151 bd de l'hopital, 75013 Paris, France. Electronic address: laurelise.gras@gmail.com.
authors.forename: Laure-Lise
authors.initials: LL
authors.lastname: Gras
authors.forename: David
authors.initials: D
authors.lastname: Mitton
authors.forename: Philippe
authors.initials: P
authors.lastname: Viot
authors.forename: Sébastien
authors.initials: S
authors.lastname: Laporte
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D004548:Elasticity; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008875:Middle Aged; D009126:Muscle Relaxation; D009334:Neck Muscles / Q000502:physiology*; D014783:Viscosity
keywords: Biomechanics; Generalized Maxwell's model; Human muscle; Relaxation test; Viscoelasticity