Thanks for all of the suggestions! This will be a long post...
There is a low horse stance, but in my month of training so far, we mostly use horse stance when doing side kicks. I'm training in Shotokan, btw. In my old style from 15+ years ago, we frequently did horse stance with punches and blocks, probably every class. It's funny that you should mention it, because I was thinking to myself last night that I should practice that at home in front of a mirror. I think I know what you mean by half-moon walking - I do this by itself periodically and try to do it on a regular basis during training. Good to know it can help with posture!
Thanks for the suggestions. I'm sure it will feel weird sitting or walking with proper posture at first. Anytime I've purposefully tried putting my shoulders back and my chest out, I always felt like Mulan in the scene where she walks into camp looking like an idiot trying while trying to "walk like a man." If you're not into Disney, here's the clip:
Oh, that looks like a fun exercise!
Good to know that the shoulder hunch is common and I'm not a weirdo. Well... maybe I am weird, but not because of that.

My sensei suggested that many of my issues will likely resolve if I can get my posture right. Good suggestion for punching the air, too! No one has commented on my shoulders when I punch the bag or other target, but it keeps getting brought up during kata and drills. So I'm assuming that I either don't hunch when hitting a real target (or not as much), or no one has noticed somehow. So perhaps the issues is indeed in targeting.
Thanks for this! I definitely look like one of those poor posture dudes in that article. I've read about foam rollers for dealing with sore muscles - I didn't know you could use them like this for posture improvement! I'll order one and try it out. Maybe it will also help with some lower back pain I've been experiencing as well. I'm not sure about that physio ball, though. Not that it isn't necessarily a good exercise, but I'm wondering if I can do it. I suppose I could plop onto a pillow or something and see if I can at least move like that. Maybe I'm thinking it requires more core strength than it really involves.
Good luck with your recovery!
Hmmm, interesting. My car doesn't have this, but I also don't spend much time in the car normally. I wonder if it's worth getting a pillow? Then again, it might also be useful for the office chair.
I have actually never done this kick! This sounds like an amazing cardio exercise. I'll have to give this a try once I learn how to properly execute it... which may be hard because I was never good at jumping even when I was a teenager.
Sorry,
@dvcochran, most of the folks who have replied so far have seen my other posts. I am about a month into training in Shotokan after about a 15 year hiatus from training in a different style of karate. Formerly, I was a purple belt (yonkyu/4th kyu), but now I am a somewhat coordinated white belt that is good at some techniques and miserable at others. I am in the dojo 3 days per week for about an hour and 15 minutes each. I also do a 50 minute class at my university twice per week (although I've had to miss a few of these lately). I'm also very overweight, although I don't think that impacts my posture too much.
I was a slouchy kid. I used to get yelled at in band all of the time for slouching in middle school. I imagine my posture got better in high school because it wasn't an issue when I studied karate. College was a never ending slouch fest, and I'm a slouchy grad student now. I rarely sit in a proper office chair! So the slouch is probably caused by all of the things you suggest, except for glasses (since I don't wear them).
My instructors have both pointed out my posture, although they are less concerned about posture and more concerned about things I do that are connected to posture, like poking my head forward when I punch or step. However, they said that I could best solve the problems by fixing the posture problem. The advice I got was to be mindful of my posture and work on keeping my shoulders back and my arms close to my body (I sometimes flare out my elbows and do other weird things with my arms). Easier said than done since as soon as I stop thinking about it, my posture goes to heck again! I'll be trying out some of the exercises posted above, but I'll also look into additional posture exercises on YouTube.