7.7.2 Contacts considered when seated in a chair

When the model is seated in a chair, Ergoniza Intelligent establishes four equivalent support points for biomechanical calculation: one at each knee and one at each hip. The points located at the knees do not necessarily represent physical contact between the knees and a surface; rather, they are calculation points used to model load transmission toward the front of each side of the body.

The model therefore assumes two support areas on each side: a front support located at the knee and a rear support located at the hip, in the area of the ischial tuberosity. This simplification allows the same general framework used for other support situations to be applied, representing the contacts as points and linearly distributing the vertical reaction components between them.

The feet may remain in contact with the floor, and this condition continues to be detected by the system. However, when modeling seated posture in a chair, foot contact with the floor does not change the definition of the main supports on each side, which are the corresponding knee and hip. Foot contact is subsequently taken into account when calculating joint loads at the ankles, knees, and hips.