Ok, I'll see if I can explain it well. This is mostly in the individual class, although there has been a bit of it the last 2 weeks in group class, and there used to be more in our practices.
On the day that it is individual class, once Delta realizes it is day for violin class, he will get upset and have a little mini-tantrum. (jump up and down a few times whining.) - when it is time to go, he will say stuff like "I don't want to go to Miss A's", but will get ready. When we get there, he may or may not try to avoid getting out of the car. We go into the class, and he is polite to the teacher, says hello and everything, and gets ready.
The class will vary a bit on various factors - stuff like how he is feeling, and a bit on what he is being asked to do. Usually (unless he is having a bad day over-all) - it starts out pretty good, and he is co-operative. Very occasionally, he will make it for most of the lesson (30 minutes) before he "acts up" - which I figure on those occasions it is just that he has reached his limits. But if something happens that he doesn't like, he will sort of shut down. He might start by saying his legs are tired, or his arm is tired. Or he might just pretty much lie down on the floor and ignore the teacher - or may start sort-of drawing on the carpet with his fingers ignoring the teacher. Basically it comes down to ignoring the teacher. Or if the teacher is trying to fix his technique, he may just continue to do it his way, maybe shaking her hand off of his shoulder or hand or whatever.
Things that he might not like that can cause this - if playing a game such as snakes & ladders with violin things to do on them --- getting a square that he doesn't like (either it has a snake, or has a violin activity he doesn't like.) - same type of thing with the fishing game - getting a card he doesn't like. The teacher trying to get him to do something differently from the way he is doing it. Being asked to do something he considers "too hard" (mostly playing with doing fingers instead of open E - although he is slowly betting better at that.)
The teacher generally would end up ending the lesson - which I guess worked with other students she has had after a few times. But my son just seems relieved. The last few weeks the teacher has been just using the games instead of trying to teach, just trying to make the lessons a happier experience, and then his last lesson, she tried to gently correct technique, but backed off when he showed signs of resistance - and after that lesson is when she said that she still thought a long break was the best option (but that she would talk to his group teacher to see if she had room to take him, as I've indicated I would prefer trying a different teacher instead of a break.)
For his group lesson, he had been participating happily, doing everything for a whole hour class (which was basically playing the violin for the vast majority of the time) until 2 weeks ago. 2 weeks ago a few things happened. We had gone to observe a class of another student with his indiv. teacher that day (only day with boys about his age, just a bit ahead of him, that wouldn't get distracted by him) - it happened to be his dad's birthday - and the group teacher started "teaching" all the students to play twinkles using the fingers instead of open E. (It is an early book 1 class with beginners to kids that are a few pieces into book 1 - but most of them are pretty close to my son's level at this point.) I think the combo of all of those was just too much for my son, and he spent a lot of that class spinning around on the floor, with me holding his violin and bow so he didn't knock it. Last class was a lot better, but anything they were asked to use fingers, my son sat on the floor.
What my son has been telling me is basically that "I might play it wrong", or "I might make a mistake". So it appears to me that I have a boy that has the type of perfectionism that paralyzes him. He doesn't want to do something until he knows he can do it - which makes it hard to teach him anything new. I have personally experienced that type of perfectionism, and I know how hard it can be. I am fairly sure that his stomach gets all tied into knots before class. His teacher is aware of this too. I talk to him, and I've asked him what he thinks will happen if he plays it wrong - but he can't verbalize what he is worried about.... and I've told him that I'm not worried about him doing it wrong, that I just want him to try - and that this is how you learn, etc. His teacher is very strong on technique, and seems to require a pretty strong technique before advancing - which I think may be making the perfectionistic tendancies of my son worse - and I think originally made him a bit bored because he wanted to play the violin. (He was on a box violin for about 3 and a half months - then couldn't play on the violin for a couple more months... etc.)
As for the power struggle - I think he is just struggling to get the lesson over, and to get out of having to have lessons with the teacher. I'm not sure that he would necessarily be able to verbalize that - but he is basically struggling to play the violin the way he wants to.
I realize that his teacher may have a different viewpoint on things. Because he is so resistant to any correction on technique, she feels that switching teachers won't help, as any teacher would have to do at least some corrections. All I know is that there is the student-teacher-parent triangle. I can't change the student, and I can't change the parent except for changing how I do things..... and he seems to do things better for me than for the teacher. So what else does that leave me?
My son was one of those kids that wanted to play the violin on his own idea. When he was 3 (almost 4), we went into a music store, walked by a lot of instruments - he saw a violin and said it was his violin. I told him it wasn't, and he suggested it was his "present violin". He loves music, and really loved the violin. Of course he wouldn't realize the process to learn to play - but he does still have moments when the love of it comes through still. I don't want that love totally doused. He loves to play to visitors to our house, or sometimes for his dad. He isn't always happy to practice, but they have been going a lot better.
Just one up note here - last night during practice, my son chose to play Twinkle var. A - WITH FINGERS - totally on his own choice.