Proprioception (/ˌproʊpri.ɵˈsɛpʃən/ PRO-pree-o-SEP-shən), from Latin proprius, meaning "one's own", "individual" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement.
The proprioceptive sense is believed to be composed of information from sensory neurons located in the inner ear (motion and orientation) and in the stretch receptors located in the muscles and the joint-supporting ligaments (stance).
When doing a motion or exercise if you don't have good proprioceptive sense or proprioception then you will not feel the muscles needing to engage in that exercise and really all you're doing is moving wait for going through the motions this can be bad because if you don't have tension within targeted muscle you will eventually do something incorrect and lead to an injury or pain. It is crucial to have proprioception of your body to know where and what is going on because you need to master ceiling the correct a muscle so that you get your results quicker and safer.
If somebody is having trouble with proprioception typically we modify the exercise to a level 1 exercise and try to really target that muscle in an isolated movement with slow and controlled contractions and relaxation with a full range of motion. Sometimes it helps to close your eyes and really think of the muscle you are trying to feel sometimes it helps to touch the muscle the targeted muscle you are trying to feel and sometimes it helps just going slower and more controlled and really focusing on the short mid and long range of the motion and finding where you feel that contraction the most.