Proprioception could be defined as body awareness, the ability to feel our body and how the parts of our body relate.
In this case "feeling" should be differentiated from feelings.
The goal here isn't to say that feelings, or having them, is bad. But some of the sensations that your body generates can be used to sense what the body is doing, and what is being done to it, by things in the environment or the environment itself.
The main generators of "feel" in our body are our muscles.
Muscles create sensation directly, within the belly of the muscle. This could be thought of as muscle tension or muscle activity. Not necessarily a bad thing in this case, simply a tool we can use to feel our body and understand it.
Through their actions, muscles create changes in tension in the connective tissue network of the body. This tension can be varied within the ligaments or tendons or it may be varied in connective tissue within the belly of a muscle itself.
In any case, the changes in tension in connective tissue are also qualities that we can learn to feel and get information from.
Learning to consciously proprioceive is simply a matter of putting the awareness in the right place within the body so that you can feel what is happening.
That can mean learning to feel muscles themselves activating or relaxing. It can also mean learning to feel changes in connective tissue tension as muscles activate or relax, or undergo changes in activation levels.
To create movements our body activates muscles in particular ways. For the most part we are unconscious of those changes.
To become conscious, we can repeat isolated movements while focusing on either muscles or connective tissue that are involved in the movement in a big way.
The bigger the range of movement, and/or the greater the differences in sensation between endpoints of the movement, the easier it can be to learn to feel the changes in muscle activity or connective tissue tension that drive the movement.
The important thing is to create some change that you can feel, and to repeat that change.
Where information on relationships and changes in relationship within our body is signalled by changes in tension and muscle activity, information on how our body relates to the earth can be signalled by changes in pressure.
And so a good way to get better at feeling how we relate to the earth is to create changes in pressure.
Read Yoga Balance Poses for more on this.
Conscious proprioception isn't just learning to feel the body.
It's learning to feel the body and from those feelings or sensations figure out what the body is doing.
How many times have you been video'd and while being video'd think you look fantastic, and then when you watch the video realize that you don't look quite as good as you imagined?
Conscious proprioception is about learning to feel your body in such a way that what you imagine you look like, based on what you are feeling in your body now, is what you actually look like.
It's about getting your mental image of what your body is doing to more closely match what your body is actually doing.
And ironically, it's also about not thinking about how you look, but instead focusing on what you are doing.
Speaking of video, one way that you could possible improve body awareness is to use video.
The trick would to video yourself in short stages. Then watch the video and see how much what you actually look like in the video matches how you thought your looked.
Repeat the process using the same movement until your imagined movement matches the video'd movement before moving on to your next pattern.
One goal of developing conscious proprioception, whether you use video or not, is to improve our ability to feel and control our body so that our mental image of what we look like, based on what we can feel, is as close a match as possible to what we actually look like.
It should also be noted that this is a recursive process. We can continually refine our conscious proprioception.
Another goal of proprioception is that we can, if we choose, use less effort to do the same task, or we can do it in different ways.
Yet another goal of proprioception is that we can enjoy the experience of our body while we are using it. In this case proprioception is about tuning in to what is happening now. And the way that we do this is by tuning in to our body so that we can feel what it is doing and what is happening to it now.
When coordinating actions across time, it helps if everyone uses the same clock and to that end, a group of soldiers each with individual tasks synchronize watches so that they carry out their tasks at the right time.
In a similar way, it helps to have calibrated instruments when trying to do really accurate work, say in the engineering or scientific world.
Using a Torque wrench as an example, torque wrenches have some sort of dial or indicator to show how much torque is being exerted on whatever is being turned and tightened.
If a torque wrench hasn't been calibrated, then there is no guarantee that the torque that is shown on the indicator actually matches the torque that the wrench is outputting.
During calibration, a torque wrench is tested using a known quantity and if the torque shown doesn't match the torque produced the indicator is adjusted until it is.
And rather than just testing at one value of torque, for a wrench to be properly calibrated it will be test throughout a range of torque values.
In the same vein, I remember in one of my first chemistry classes our teacher taught us how to always gaze at the measurements of a beaker from the same angle when measuring fluid volume to eliminate parallax error. We learned the same thing in bartending class.
The point here is that if measuring instruments need to be calibrated so that what they indicate matches the actually quantity being measured, then this same process should be used so that our perception of what our body is doing actually matches what our body is doing. This can be easier to do if we focus on clearly defined parts of the body in relative isolation.
Why improve muscle control?
Muscle control not only helps you to control your body, it also helps you to feel it.
Muscle activation creates the tension that not only moves your body, but helps you to "sense" it.
With better muscle control you can use your body with less effort and make it easier to balance, improve flexibility and deal with pain and poor posture.