Finite element modeling in the musculoskeletal system 21
2002), a number of FE models have been developed to describe the active
behaviors of skeletal muscles. Tsui et al . (2004) constructed a 3D active FE
muscle model by de ning a user-de ned muscle behavior. The proposed
model with active components analyzed the mechanical behavior of a mus-
cle–tendon complex during isometric shortening and lengthening contrac-
tions. The simulation results of the isometric force–length relationship and
force shortening contraction demonstrated the potential of the model for
studying muscle damage and fatigue. Tang et al . (2007) developed a 3D FE
model of skeletal muscles by integrating a modi ed Hill’s muscle model
with a muscle fatigue formula, ...