Suchergebnisse

Objective: The authors sought to use biomechanical measures, including motion and pressure, to compare four office chairs. Background: The fit of a person to a chair is related to the geometric and kinematic compatibility between the two. This geometric compatibility influences the motions that are allowed or prohibited and the support pressures at the body-chair interface. Thus, during evaluation, it is necessary to treat the chair and user as a system. Method: Four dynamic test conditions were evaluated with 14 participants of varying anthropometries. Test conditions were selected to compare the ability to accommodate primary and secondary motions (recline and spinal articulation) of seated occupants. The ability of a chair to allow recline, yet maintain head and hand positions, was compared across chairs. Also, the ability of each chair to allow and support spinal articulation was evaluated. Motion data for the chair, head, thorax, pelvis, and extremities were collected along with chair back pressures. Upon completion of testing, subjective assessments were also conducted. Results: Statistically significant differences were found between chairs relative to head and hand motions. Also, significant differences were noted for the chairs' ability to move with the body during spinal articulation and the ability to provide support. Subjective assessments also yielded differences. Conclusions: Biomechanical analyses using motions and pressures can be conducted on office chairs with significant differences detected in their performance. Application: Biomechanical assessments can be used to compare and contrast office chairs in terms that are relatable to fatigue reduction as well as operator performance.

For dynamic simulation of human movement, segment axis systems are often defined by the inertial tensor unique to each simulated body segment. When empirical three-dimensional data are sought that describe either the mass distribution or the kinematic properties of the human body, anatomical frames of reference are needed for the sake of measurement methodology and data comparability. Anatomical axis systems are based on anatomical landmarks that must represent functional and stable features in the skeletal geometry. The role of anthropometric landmarks used in defining anatomical coordinate axis systems is discussed with examples from current research regarding the kinematics of the hip joint and mass distribution of the whole body. The use of anatomical frames of reference will improve the correspondence between computer simulations of the human body and the biological structure.