The Moral of the Story

 You can look fit and strong on the outside but still be physically weak on the inside....

Having a teacher that has little or no knowledge of anatomy and injuries that can be debilitating, will more than likely be detrimental to your overall health and your training. It's why some of the more reputable larger Karate organizations have educational training programs in place for their instructors. The KUGB for example and the AKF to name but two have such programs in place. How do I know? well, I've successfully completed the training of both.

Weight I was struggling to move around, walk with, lift and hold a couple of years ago, is now somewhat easier. My body has repaired from the tears it was suffering from. Had I have kept going along the road I was then my abilities today might be quite different. 

We have to recognize in our training as to what is good for us, but moreover, we need to recognize that which is bad. This includes the people around us, those we train with and even possibly the Sensei who expects that which we can not possibly give, or chooses to ignore limitations we have. 

Karate, among other things should be enjoyable, tough but enjoyable, once it isn't, then there's a problem. 

Being mindful of the job you do too must be considered when training. Doing manual work is quite different from pushing a pen around a piece of paper, working from a laptop or sitting listening to someone's issues. Training may have a greater impact on the manual work you do, yet the later not so much.

The moral......

It doesn't matter how good the Karate/Training is, if, over time you think it is a bad fit, look else where or simply leave.