I don't think about "progressive overload" and "strength training." My business is a trade, and a long day on a roof is a workout in itself. The most valuable lesson I've learned about avoiding burnout is simple: you have to listen to your body and your mind, and you can't push yourself every single day.
I learned this the hard way. Early on, I was trying to do too much. I would push my crew and myself to work long hours, and we were all getting exhausted. The work was getting sloppy, and we were making a lot of mistakes. The burnout was real, and it was a direct result of my poor judgment. I was pushing myself too hard.
The "balance" I found was to start making my crew and myself take breaks. We now have a mandatory break every two hours. We'll get a drink of water, we'll talk about the job, and we'll just get our minds off of the work for a few minutes. This simple "recovery" has a huge impact on our business. We're a lot more focused and a lot more productive.
My advice to any business owner is to stop looking for a corporate "solution" to your problems. The best way to "avoid burnout" is to be a person who is committed to a simple, hands-on solution. The best way to "find a balance" is to just listen to your body. A tired crew is a bad crew. The best way to build a great business is to be a person who is a good craftsman.