# Calculation of the muscle-induced forces on the finite element mesh
In this section, muscle forces are converted to finite-element forces acting on the nodes of the surface mesh of each muscle group. The 3 loading models proposed by Grosse et al. (2007) have been implemented in python with a special care about efficiency.
In this section, muscle forces are converted to finite-element forces acting on the nodes of the surface mesh of each muscle group. The 3 loading models proposed by [Grosse et al. (2007)](https://doi.org/10.1002/ar.20568) have been implemented in python with a special care about efficiency.
In the simplest model – the Uniform-Traction model – the total traction force $`\bar{F}`$ applied by a muscle on the bone is uniformly distributed on the surface mesh of the muscle attachment. For each triangle of this mesh, the traction is assumed to be directed towards a focal node modelling the opposite muscle attachment (see Figure 1).
