My knives are always falling.

[Paddington]

I've been practicing with the knives a lot of late.

The other day I really got into it and before I knew it, 90 mins had passed. Needless to say at this point my arms were very tired though extremely relaxed, to the point that they felt like they were floating on air.

It was in this tired state that I found my movements had to change, if were to continue with the practice. I found it easier to find the natural center of gravities and pivot points on the knife; I felt like I had to use gravity in my favour given the weight of the knife and my tired state. It felt like my knives were always falling and my movements became more crisp and defined.

Anyway, are there any existing diagrams or statements as to the different center of gravities and natural balance and pivot points on the knives, with respects to when they are in different positions? I am thinking here in terms of the type of diagrams and statements that we see in physics books (for 16-18 Yr olds and 1st year Uni students).

Just to add that, yes, I know balance and pivot points etc. will vary form knife to knife but there seems to be similarities across the spectrum of blades I have tried.

EDIT: I would like to also ask that if such diagrams don't exist, would people people find it useful if they were then provided?