I don't know if the thousands of people who find our little forum searching for these terms are even at all therians.
If you are not and you found us, welcome to our weird little corner of the internet! I recommend our main site to help you figure out what we are all about:
If you think you are a therian, and you are into quadrobics... I hate to be the one to break it to you but: While it is a much hyped-on trend on TikTok, being into quadrobics doesn't really make you a therian.
There is already another thread explaining our sentiments on quadrobics:
Opinions on Quadrobics
That being said, I should mention that I've personally been into quadrobics before it was cool, inciting much concern from our fellow community members at the time:
My basic idea was that by training up to be capable to go down on all fours I would have an easier time communicating with other canines and therefore ease my species dysphoria. I imagine something similar applies to other therians who are into quadrobics these days.
If you're wondering how that worked out for me and in order to answer the question in the title of this post: I continued it until I hurt my back doing it. I ended up going to a doctor and asking them about it... they gave me a pamphlet on exercises to do to avoid back issues. In the pamphlet, were the same quadrobics exercises I was doing when I hurt my back in the first place.
Therefore: Is quadrobics bad for you? Yes, you could hurt your back doing it. Is quadrobics good for you? Yes, it can help prevent back issues.
In other words, you can do it, it doesn't matter.
Just as with any other exercise, warm up first, don't overdo it and do it regularly instead.
As for how widespread it is -- it's mostly only done by younger therians. When you get older, get some health issues and such, these things become more complicated to keep doing.