Re: A simple mechanical model of body use.
Hi Chris, all
A few things to cogitate
Gravity acts on every mass component in the diagram and so the gravity vector under the body is potentially misleading, you might like to consider it as a resultant force vector on the ground that can have a direction other than vertical, or separate out the load onto each of the feet, in doing so there is a kind of fulcrum effect. Where the net vector falls outside the base of support a fall starts (thing this you have talked about earlier though)
The feeding back from the ground Hunter alludes to is the ground reaction force and its direction can be varied and infinite (to the limit of the structure that propagates it) which is very cool I think!
Static loads are a good place to start and interesting but where it gets really interesting is exploiting this analysis not only in nage but also in uke to ensure maximum effect.
I wonder/suspect if the coiling/winding/reeling/spirals are part of the methods of tightening up structure to be able to propagate and direct the forces
look forward to the next versions and where your heading
PS FWIW on the subject of the jo trick, I heard from one O'Sensei's deshi that he was asked to pull back on the other end of the jo. be interested to hear more on the replicating of it - have some limited success on a single outstretched arm