In the martial arts, Tai Chi is the obvious answer.
Consider Aikido. It’s generally more like choreographed exercises. A lot of dojos are very understanding of physical constraints. Check with your doctor, it might be good way to gently test your limits. Plus, it’s important to know how to fall safely.
Evil Genie: “Granted.” It starts to rain. It never stops.
There are countless other ‘niche’ communities that have no posts for months, however.
Hey, have you seen !fedigrow@lemmy.zip? It’s got a lot of discussions on how to handle this.
I think that to grow a niche community, you need at least 2-3 regular posters, and you need to make posts that encourage discussion (i.e. ask questions or provoke a thoughtful reaction that readers would like to share.)
Also keep an eye on: https://piefed.fediverse.observer/stats A couple thousand people (and several communities) moved there after lemm.ee died, but we interact with lemmy.
As for why it subjectively seems to be declining… maybe you know what you’re gonna see in New, and so you engage less with posts? Maybe it’s time to be more of a poster!
Boston is so awesome. You didn’t mention the museums, historical places, concerts, festivals, theaters, hundreds of little cafes and restaurants, bookstores, art galleries, several dozen universities each with events open to the public. Taking the T (public transportation) over to the Boston Common to see what’s going on, then walking through downtown, maybe stop at Fanueil Hall for a snack, then go all the way to the North End to a restaurant. Oh gods I’m homesick and I only lived there like 8 years.
Aw yeah, if you already know your rolls and breakfalls, Aikido is a great thing to check out. At lower levels, the “attacks” are basically two-person katas, usually involving escaping from grabs. At upper levels they do have something called randori but even then it’s all very structured. Aikido gets made fun of sometimes for not having a “live” adversary who’s actively trying to beat you. I’ve read there are some dojos that do competitive Aikido, but I think that’s rare.