title: Tonic finite element model of the lower limb.
abstract: It is widely admitted that muscle bracing influences the result of an impact, facilitating fractures by enhancing load transmission and reducing energy dissipation. However, human numerical models used to identify injury mechanisms involved in car crashes hardly take into account this particular mechanical behavior of muscles. In this context, in this work we aim to develop a numerical model, including muscle architecture and bracing capability, focusing on lower limbs. The three-dimensional (3-D) geometry of the musculoskeletal system was extracted from MRI images, where muscular heads were separated into individual entities. Muscle mechanical behavior is based on a phenomenological approach, and depends on a reduced number of input parameters, i.e., the muscle optimal length and its corresponding maximal force. In terms of geometry, muscles are modeled with 3-D viscoelastic solids, guided in the direction of fibers with a set of contractile springs. Validation was first achieved on an isolated bundle and then by comparing emergency braking forces resulting from both numerical simulations and experimental tests on volunteers. Frontal impact simulation showed that the inclusion of muscle bracing in modeling dynamic impact situations can alter bone stresses to potentially injury-inducing levels.
authors.affiliation: Laboratoire de Biomécanique Appliquée, UMRT24 INRETS/Université de la Méditerranée, Faculté de Medecine secteur nord, Bld Pierre Dramard, 13916 Marseille, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Behr
authors.forename: Pierre-Jean
authors.initials: PJ
authors.lastname: Arnoux
authors.forename: Thierry
authors.initials: T
authors.lastname: Serre
authors.forename: Lionel
authors.initials: L
authors.lastname: Thollon
authors.forename: Christian
authors.initials: C
authors.lastname: Brunet
mesh_terms: D000063:Accidents, Traffic; D003198:Computer Simulation; D020342:Finite Element Analysis; D006801:Humans; D007866:Leg / Q000503:physiopathology*; D007869:Leg Injuries / Q000209:etiology / Q000503:physiopathology*; D008954:Models, Biological; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000503:physiopathology*; D004856:Postural Balance