Proprioception utilizes the physiological components of the nervous and
musculoskeletal systems to allow an individual to sense the position of their limbs
subconsciously. By providing a rigid connection to an object this proprioceptive ability
can be extended to the object and allow the user to sense the spatial location and
orientation of these objects with respect to his or her body. This concept explains how a
person can use a tennis racquet to hit a tennis ball without having to observe the position
of the racquet during their swing or the way a blind person uses a long cane to ‘feel’ the
location of objects in their surroundings.
Body-powered prostheses take advantage of this proprioceptive ability by relating
the motion and position of the prosthesis to the motion and position of an intact joint of
the amputee via the control cable. However, most externally powered prostheses do not
have any mechanism with which to provide feedback regarding the state of the prosthesis
to the proprioceptive system of the amputee. In these cases the amputee must rely on
vision and other incidental sources of feedback such as motor whine and socket pressure
to control their prostheses and this may place a significant cognitive load on the user