Knee forces during the activity of getting out of a chair with and without the aid of arms.

This is a preliminary study of the knee forces during the activity of getting out of a chair with and without the aid of arms. The equipment limited the study to the phase of the activity where no contact occurred between the subject and the chair seat. The model of the knee considered was two-dimensional, and quasi-static. Analysis showed that the forces acting in both compartments of the knee were comparable with those occurring during other non-strenuous activities such as level walking. It was also shown that the use of arms to aid rising from a chair causes considerable reduction in both joint and muscle forces.