In engineering, iso-elastic refers to a system of elastic and tensile parts (springs and pulleys) which are arranged in a configuration which isolates physical motion at one end in order to minimize or prevent similar motion from occurring at the other end.
This type of device must be able to maintain angular direction and load-bearing over a large range of motion.
The most prominent use of an iso-elastic system is in the supporting armature of a Steadicam, used to isolate a film or video camera from the operator's movements.
The result is that the spring-pulley system can produce a fairly constant tension in the cable over a large range of movement.
As a result, the camera doesn't bounce up to the 'balanced' position after a move, for example when the operator steps up onto a curb from the road.