I am 'rolling eyes ' becasue you, as many use a 'phrase' WSL used and turn it to however you interpret it ...NOT! He refered to the strict elbow training of VT , to not be 'thought about' while fighting. IOW dont concern yourself with training mind. Not do anything you like ...then it wouldnt be VT as many do anyway .
Look i have met people FIRST HAND who do the K1 idea ...ME not I heard someone do it or saw a clip...and I can show you the errors COMPARED to VT ...YOU can do ANYTHING !! lmao..you can jump up and down before a fight, crouch, do the crab, etc....
As i mentioned the 'balance' point isnt ON the heels, BUT when you deliver the Quadriceps force [largest muscle group of the leg] you use the heel to drive [milliseconds] into the ground for the force you generate into your arms via the structure. This in physics is referred to as equal and opposite force, I drive 200lbs of force into the ground with my leg and depending on the alignment of my hips /structure/elbow angles, I can deliver that same force, using timing distance and movement etc...CK helps us for this. Body weight momentum driven by this sudden force generation at close range coupled with simultaneous arm actions is our aim.
If you add the hinge joint of the ankle you engage the calf muscles you lose the quadriceps, why we 'shuffle' , to allow us to repeat the same heel into ground THEN toes. We DONT take large steps becasue we LOSE the quadriceps under contact with the opponent. This force is invisibleso you cant see it in clips ...its hard to deliver unless coached , because guys ( some guys on this forum I have met ) compensate for lack of this ability by using upper body /leaning. Big tall guys especially ;) Also due to the nature of their attempts to fight in 'contact' its easy to feel a wave and trough of energy, ~ you can dial into their timing instantly and counter them mercilessly ....:)
Try standing off the ground with your heels and on the balls of your feet/toes and you immediately engage the calf muscles. then try to deliver leg force....you have to use heels, but not weigh back on the heels as mentioned in previous posts.
The other point to keep in mind is our axis line, running down our center. If you shift this under pressure of engagement you will allow ME :D to unbalance you as you move.
.One of the key elements of VT movement is to align the hips in a smooth facing attack towards your intended victim. Not a lot of guys i have met can do this and maintain a flatline of energy at me at the same time...very hard to correct mistakes while I am doing this AT YOU..iow you make a footwork mistake like moving your front foot first while moving sideways/backwards under pressure and you wont regain your balance.
words, but showing and feeling takes less time.
Chi-sao allows us to isolate the axis lines while doing bong /jut-lop sao drills. So when you are suddenly pulled by an opponent you shift with axis line vertical EVEN under sudden pressure randomly applied...basic thing that MANY fail....pressure testing in chi-sao for fighting .
Seung ma toi ma drills also focus on the heels as the driving point for drilling, delivering the 'unseen' force of the leg via the tan sao / jum sao punches.....small steps allow this.
A way to analyze systems that dont do this, they 'sway' or step with lead leg THEN drag the rear...or the step lead foot then and lift the rear to make the stance equal again....don in stages you lose the body weight momentum, iow we try to harness our forces available to us using simple physics. bodyweight in motion under control, ballistic displacement of parries and strikes simultaneously, energy [not seen] from the quadriceps shuffling, being driven by the heel INTO the ground while maintaining our balance on the whole foot...air hockey puck.
Chi-sao prepares us to MEET these forces in the SUDDEN clash that we enter into while fighting ..iow we train chi-sao MOMENTS of distance etc....for reflex reactions to attempts to stop us ....and NOT be taken advantage of ourselves...like bad stance , bad foot positions, bad elbows etc.....
the actual fighting is simple compared to the drills.