In the DESCENT rather than lowering yourself with tension, use the breathing in order to relax yourself downwards progressively switching of the necessary tension required to keep you standing. It's like taking the remaining tension holding you up, and funnelling it down and out through your body. However if you are doing this the tension has to have somewhere to go otherwise it'll just linger in your body and disable your ability to go lower in the squat with relaxation. This is where the connection with the feet comes in. When the soles of the feet (except for the arches as they ideally should be off the ground unless you are a flat footed) come up off of the ground, that is usually indicative of excess tension that is being stored in the body. That excess tension leads to fatigue, depleting the oxygen supply, and also just simply restricting relaxed movement. So if you notice the soles of the feet coming up, you then check yourself and see where tension is building up preventing your descent whilst being able to keep the whole soles of your feet completely flat on the ground. This is diagnosis of tension, and then you will have to remedy it though breathing and relaxation. Once you have relaxed to the point where you can go down in the squat with the soles of your feet flat on the ground, there is some good news: There is now a path for any remaining EXCESS tension to go in order to exit your body rather than building up. The storage of excess tension in the body creates the a disconnect in the body so it is no longer one piece unified by relaxation in effect destroying the form. You can have what appears to be good posture on the outside but if this excess tension and disconnect remains, then that good posture does not mean that there is good form. You can of course have just right amount of tension to hold shape (form) and perform the activity however it is now evenly and appropriately distributed throughout your entire physical being. This is because of the other good news: When you can keep the soles of your feet flat on the ground is that it begins to properly use the skeletal structure as support without having to rely on excessive activation of the musculature (excess tension) in order to perform the activity.
In the ASCENT by keeping the soles of the feet flat on the ground and pushing up I have found that it enables me again to utilise my skeletal structure in order to rise and keep the necessary shape and posture, whilst I can then also allow my muscles to relax (aside form the ones required to perform the task) and use breath and very minimal movement in order shed the excess tension. Going up from the squat by nature of the movement and the fight against gravity tends to accumulate more excess tension especially when you go slower. Keeping the soles of the feet flat on the ground and pushing the ground away from you seems to have the affect of (and bear with me here):
Being able to funnel the excess tension down throughout the entire body around the skeleton and to the feet connecting the entire body for the soles of the feet to the top of the head and everything in between through relaxation. This I believe is good form. The change of shape and maintenance of structural integrity and the even and appropriate distribution of tension by way of relaxation evenly throughout the whole being.
So what's the practical application of this you ask?...Well I reckon this is pretty good:
Systema Sydney Russian Martial Art