Structure development, Chi-sao, to me is a method to refine the 'bow' to my arms the 'eternal arrows' . If the bow isnt drawn in full 'load' to release the arrow then I dont have maximum available force, so Iwork on the bow )- , or vt structure in chi-sao. To develop a power source to release shots from, in a unified package, ie parry, punch, body all coming at once.
Iow I need powerful punches in close quarters to come from an energy source that isnt the 'arrows' or arms alone. I need momentum from a structured moving power source , driving into and from the ground up through the structured chain to my knuckles.
Newtons third law
Like the back cast of a fishing rod to harness the load potential into the forward cast, or drawing back on a rubber band...load is a word for stored potential energy.
For VT purposes the 'bow' or structure, is a crossbow capable of tremendous close quarter penetration with minimal drawing back , telegraphing, to 'reload' the arrow .
SLT , our feet positions support the hip , our knees, hips, spine, shoulders, elbows, wrists, are all aligned to harness the potential force of the bow )- structure.
With our body mass in motion, shifting, facing a target with unpredictable motion, and shooting back too , hopefully with less attention to alignment, balance, timing, etc...
The bow )- structure, also has to stay constantly loaded, forwards, moving back, at angles to counter attacks. Seung ma toi ma drills, with angling, shifting to attack, etc...We can drill specific areas of the stance, structure by isolating certain drills.
We can push pull, etc... but as tests, not to replicate as sumo in sparring Some confusion arises from students who think the drill test is the fight application.
Chum Kil teaches the bow ) structure, to now move in its intended vertical axis line. Also using sudden twisting torquing action to further add to the structures potential to unleash controlled , aligned force.
So a large part of the VT regimen is chi-sao drilling , not as a arrow feeling arrow exchange, but a partnership of bow meet bow, lets load the bows first with potential energy to send into the arms /arrows, with alignment. Lets help each other get good force exchange so when we go to fight we have this attribute that we developed together.
Chi-sao , done imo , correctly , becomes an intense exchange of force with two )-(
partners using each other to develop this lat sao chit chung of potential explosive forward arrow strikes with our arms.
We arent trying to use the tips of the arrows to play 'blocking feeling games' because we are not fighting in chi-sao, we are developing each others potential to have strong 'loaded' structures.
We, me, allow shots regularly to prove their force and trajectory, distance, allowing arrows to strike us regularly by taking our arms away so each partner can take a shot and develops mindless release of arrows from loaded structures. lat sao chit chung.
We use the chi-sao as a systematic progression of this simple idea.
Hitting a heavy bag also proves this same idea, impact. Kicking with the same ) driving hips behind the kick....