Tonic finite element model of the lower limb.

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.

[1]  M. Bobbert,et al.  Mechanical output from individual muscles during explosive leg extensions: the role of biarticular muscles. , 1996, Journal of biomechanics.

[2]  Shrawan Kumar,et al.  Kinematic and electromyographic response to whiplash loading in low-velocity whiplash impacts--a review. , 2005, Clinical biomechanics.

[3]  L Thollon,et al.  A Human Model for Road Safety: From Geometrical Acquisition to Model Validation with Radioss , 2003, Computer methods in biomechanics and biomedical engineering.

[4]  Edwin Hendler,et al.  Effect of Head and Body Position and Muscular Tensing on Response to Impact , 1974 .

[5]  B. Nigg,et al.  Biomechanics of the musculo-skeletal system , 1995 .

[6]  P Zioupos,et al.  Ageing Human Bone: Factors Affecting its Biomechanical Properties and the Role of Collagen , 2001, Journal of biomaterials applications.

[7]  Yuichi Kitagawa,et al.  A Severe Ankle and Foot Injury in Frontal Crashes and Its Mechanism , 1998 .

[8]  D. Viano,et al.  Biodynamic Response of the Musculoskeletal System to Impact Acceleration , 1980 .

[9]  S. Robin,et al.  HUMOS: HUMAN MODEL FOR SAFETY - A JOINT EFFORT TOWARDS THE DEVELOPMENT OF REFINED HUMAN-LIKE CAR OCCUPANT MODELS , 2001 .

[10]  F. Zajac,et al.  Muscle coordination of maximum-speed pedaling. , 1997, Journal of biomechanics.

[11]  V. Edgerton,et al.  Muscle architecture and force-velocity characteristics of cat soleus and medial gastrocnemius: implications for motor control. , 1980, Journal of neurophysiology.

[12]  F.E. Zajac,et al.  An interactive graphics-based model of the lower extremity to study orthopaedic surgical procedures , 1990, IEEE Transactions on Biomedical Engineering.

[13]  F. Zajac Muscle and tendon: properties, models, scaling, and application to biomechanics and motor control. , 1989, Critical reviews in biomedical engineering.

[14]  O'Connell Al Effect of sensory deprivation on postural reflexes. , 1971 .

[15]  R L Lieber,et al.  Sarcomere length operating range of vertebrate muscles during movement. , 2001, The Journal of experimental biology.

[16]  S. Bidal,et al.  The seated man: geometry acquisition and three-dimensional reconstruction , 2002, Surgical and Radiologic Anatomy.

[17]  Andrew Petersen,et al.  Stability and skill in driving. , 2002, Human movement science.

[18]  Jeffrey Richard Crandall,et al.  SIMULATION OF MUSCLE TENSING IN PRE-IMPACT BRACING , 1995 .

[19]  R. Lowne,et al.  POSITIONING AND BRACING OF THE LOWER LEG DURING EMERGENCY BRAKING - A VOLUNTEER STUDY , 1998 .

[20]  Adam Wittek,et al.  Hill-type Muscle Model for Analysis of Mechanical Effect of Muscle Tension on the Human Body Response in a Car Collision Using an Explicit Finite Element Code , 2000 .

[21]  T Alkan,et al.  Neuroprotective Effects of MK 801 and Hypothermia Used Alone and in Combination in Hypoxic-Ischemic Brain Injury in Neonatal Rats , 2001, Archives of physiology and biochemistry.

[22]  F. Zajac,et al.  A musculoskeletal model of the human lower extremity: the effect of muscle, tendon, and moment arm on the moment-angle relationship of musculotendon actuators at the hip, knee, and ankle. , 1990, Journal of biomechanics.