Computation of segment inertial properties. The geometrical models produced by FhG from the MRI images include bone and skin meshes. The identification of the various body segments has been obtained through planes of section following previous literature on the topic (Zatsiorsky and Xxxxxxxxx, 1983; xx Xxxx, 1996). A first section plane, inclined by ~45° with respect to the transversal plane and passing through the hip joint centre, divides the pelvis and thigh. A second plane separates the thigh and the shank with a cut parallel to the transverse plane at the lateral femoral epicondyle. Finally, a transversal section plane at the height of the lateral malleolus identifies shank and foot. Using Netfabb (xxxx://xxx.xxxxxxx.xxx), the described cutting planes (summarised in Figure 13 A) were used to section the mesh of the external skin and produce the individual body segments, whose inertial properties (position of centre of mass, mass, tensor of inertia) were finally calculated in NMSBuilder. Different densities were assigned to bone (1.42 g/cm3) and soft tissue (1.03 g/cm3 for males and 1.02 g/cm3 for females), using the values reported in Xxxxx et al. (2005). A negative soft tissue density was assigned to any bone volume intersecting the soft tissue volume (Figure 13 B), so that the bone volume (including that of pelvis) was not considered both as bone and soft tissue. Figure 13: (A) frontal view of the section planes used to define the body segments in the musculoskeletal models (B) description of the different densities assigned to the element of each bones (bone, soft tissue and negative soft tissue).
