The present paper introduces a set of ergonomic factors which are evaluated by a framework that performs automatic, simulated ergonomic analysis of virtual environments. The proposed framework uses virtual user models describing users with or without physical deficiencies and evaluates the ergonomy of virtual environments for the specific users. Two novel ergonomic factors regarding comfort are introduced and compared to known physical metrics, such as torque, impulse and energy. The factors used are described in detail, according to their theoretical basis as well as their practical meaning. Experimental results illustrate the use of the proposed framework in two realistic application scenarios: a common car interior and a typical workplace design.