ABSTRACT
Human stance and locomotion are basically related to the ability of balance and the control of posture. From a behavioral point of view the goal of postural control may therefore be defi ned as to orient body parts to one another and the external environment without loss of equilibrium. In order to accomplish this task and to achieve an appropriate muscular activation, the postural system has to take into account gravitational forces. Theoretically, ‘static equilibrium’ is achieved when all moments acting on the body are balanced and a specifi c body position is maintained. However, even static seeming postures like upright stance in humans involve a great deal of neural and muscular activity and the term ‘static equilibrium’ has – despite its widespread occurrence – to be used with caution (see ‘The Organization of Un-Disturbed Stance – Reactive or Feedforward Control?’, below, pp. 260-2).
