Abstract: A protective helmet is described comprising: an outer layer (1); an inner layer (5) for contact with a head of a wearer; and an intermediate layer (3, 4) comprising an anisotropic cellular material comprising cells having cell walls, the anisotropic cellular material having a relatively low resistance against deformation resulting from tangential forces on the helmet. The anisotropic material can be a foam or honeycomb material. The foam is preferably a closed cell foam. The helmet allows tangential impacts to the helmet which cause less rotational acceleration or deceleration of the head of the wearer compared to helmets using isotropic foams while still absorbing a significant amount of rotational energy.

Abstract: A protective helmet is described comprising: an outer layer (1); an inner layer (5) for contact with a head of a wearer; and an intermediate layer (3, 4) comprising an anisotropic cellular material comprising cells having cell walls, the anisotropic cellular material having a relatively low resistance against deformation resulting from tangential forces on the helmet. The anisotropic material can be a foam or honeycomb material. The foam is preferably a closed cell foam. The helmet allows tangential impacts to the helmet which cause less rotational acceleration or deceleration of the head of the wearer compared to helmets using isotropic foams while still absorbing a significant amount of rotational energy.

Abstract: Active contour models and active shape models were developed for the detection of the kinematics landmarks on sequential back surface measurements. The anatomical landmarks correspond with the spinous process, the dimples of the posterior superior iliac spines (PSIS), the margo mediales and the elbow. Back surface curvatures are used as a basis to guide the ACM and ASM's towards interesting landmark features on the back surface. Geometrical bending and torsion costs, and the main modes of variation of the landmark points are added to the models in order to avoid unrealistic curve shapes from a biomechanical point of view. Reconstruction of the underlying skeletal structures is performed using the surface normals as approximations for skeletal rotations (e.g. axial vertebrae rotations, pelvic torsion, etc.) and anatomical formulas to estimate skeletal dimensions.