A head-mounted device includes a device housing, a support structure that is connected to the device housing to support the device housing with respect to a user, a display device that is connected to the device housing to display content, an optical system that is associated with the display device, and sensors that generate sensor output signals. The head-mounted device also includes a tension controller that determines a tensioning command based on the sensor output signals, and a tension adjuster that applies tension to the user according to the tension command in order to restrain motion of the device housing with respect to the user.