One of my goals during the pandemic is start doing this more often. I have experimented a bit in the past and let it go, now I am returning to it as a central project for three reasons.
The first and most important reason is just that I feel like it's a good time to develop personal attributes so that they are improved upon returning to in-person training. This, bagwork, makiwara, perhaps some padwork with my wife if she's willing to hold pads (she's a student of mine, though has been on hiatus for a while).
Secondarily is simply that I need to lose weight and work on my general fitness a bit, and this would be one part of that.
Third is simply that it's the closest I can get to moving in the same way I would in any kind of partner training (hopefuilly) in our current solo-training enforced environment.
The first workout I came up with is basically some warmups (e.g.knee-to-elbow, jumping jacks, light dynamic stretching), followed by repetitions of 2-3 sections of kata application 10 times or so, with emphasis on movement speed and "recovery" in between repetitions. The last bit is freeform movement in a cricle, then freeform shadow sparring while holding light weights. I like to use the corners of my room as "centerlines" to move around.
It of course can look different than kata, just as it would when applying it on a person. So far it's working well in terms of heavy cardiovascular exercise, and giving me a new way to work applications without a partner.
It was years ago that I searched for this online, but as I became interested in it this time around I ran into the same problem as I did years ago: Most of the resources online are boxing/kickboxing based, and I feel like they could be adapted specifically to a self-defense model, at least in places. Of oruse I know a part of this is just about conditioning, so I know that kickboxing/boxing tutorials are perfectly adequate for Karateka, just wanting to hear some ideas and brainstorming.
I'm wondering how other people do this, and what changes they would make to a typical shadowboxing workout, if any.