7.7.7 Scope and limitations of the seated-posture model

The modeling of seated posture in a chair implemented in Ergoniza Intelligent should be understood as a simplified biomechanical approximation. Its purpose is to provide an operational representation consistent with the rest of the system while retaining the ability to analyze stability, the distribution of reactions at the supports, and joint loads.

However, this model does not reproduce all the actual mechanical phenomena associated with interaction between the body and a chair. In particular:

• the pressure distribution over the seat or backrest is not represented continuously;

• deformation of the seat and soft tissues is not modeled explicitly;

• geometric or mechanical differences among chair types are not considered;

• partial unloading of the thigh on the seat is represented using a fixed, simplified assumption;

• the reaction force exerted by the backrest and its point of application are not calculated; its effect is represented exclusively by unloading the flexion component of the lumbar moments.

Therefore, the results should be interpreted as a reasonable biomechanical estimate of seated posture in a chair, useful for comparative ergonomic assessment and trend analysis, but not as an exact representation of the actual mechanical interaction between the body and the furniture.