7.7.3 Distribution of reactions at the supports when seated in a chair

When the model is seated in a chair, Ergoniza Intelligent calculates the distribution of the reactions at the supports using the same general principle described in Section 7.1: the distribution of the vertical reaction components depends on the position of the center of pressure relative to the base of support. The difference is that, in this case, the base of support is constructed from the front and rear supports on each side defined by the knees and hips.

Thus, the distribution of the load between the left and right sides depends on the position of the center of pressure relative to the supports on both sides of the body, while the front/rear distribution within each side depends on the position of the center of pressure between the corresponding knee and hip. Ergoniza Intelligent therefore determines the percentage of the load supported by the left and right sides and, within each side, the percentage of the reaction supported by the front support (knee) and rear support (hip).

This information is represented in the Stabilogram in a manner analogous to that described in Section 7.8. In this case, the front of the support corresponds to the knee and the rear to the hip. The footprint displayed by the system therefore represents the area defined by the supports at both knees and both hips, rather than the plantar contact area used in bipedal stance.