Everybody has sensory receptors (mechanoreceptors) in their joints, which help us determine and feel where our bodies are located in space.
If I asked you to close your eyes and hold out your arm to the side, you would feel where it is in association to the rest of your body. With your eyes closed, you will be able to feel the postion of your body. This body awareness is developed through the expirences you have with sensory input into your joints.
Proprioception sensation differs from tactile, because the sensory input originates from our joints and muscles not our skin.
When your child does not have the opportunity to gain information from proprioception experiences, they will lack the necessary body awareness to navigate our world.
Proprioceptive sensation helps our children maintain muscle tone, increase core stability and balance, and learn appriopriote calibrations of the speed and force of their bodies.
Resources:
https://www.griffinot.com/what-is-proprioception/
Living Sensationally by Dr. Winnie Dunn