Tired muscles after short amount of practicing
I practice 3 hours a day at most with 5-10 minute pauses but even then my muscles get really tired after 2 days of practicing and it usually gets to the point where I can't feel my violin, I cant feel the intonation, my vibrato feels really weak and my bow arm gets completely messed up, It's like I'm barely holding the bow. Also my back is really stiff. It gets very hard to keep playing and to practice everyday, sometimes I just want to quit forever.The first day of practicing goes great, I feel great, I play on a solid level, but two days later everything is like I haven't practiced even 1 hour. It's very hard to keep being motivated and to make progress like this. Has anyone had this problem before? Should I just strengthen my muscles or is it much more complicated than that?
Sounds like you have serious tension issues. I'm no expert on this but if you have not had a complete medical checkup in a while, it couldn't hurt. You also might see about getting a few lessons from a violin teacher who specializes in this kind of thing ... Alexander Technique or such.
I thought exactly the same thing as Paul when I read your post and second his recommendation for Alexander Technique.
Could you ask your current violin teacher for advice if you have one? I agree with Paul 100% and I also recommend getting checked out by a physical therapist with your violin in hand. They might be able to suggest exercises that can help with your problems.
How old are you?
You are almost certainly doing some major aspect of technique incorrectly. It should never hurt with the amount of time you are putting in and the breaks you are taking.
I new a girl who had a condition, where her muscles would shut off after 15-20 minutes of physical activity.
3 hours a day sounds too much, unless it is really productive, and that stage is usually at an advanced level where there shouldn't be the issues described.
Mario said in another thread that he's been playing for 13 years, so he is presumably not a beginner.
In addition to tired muscles, Mario has expressed issue of apparent lack of progress. I guess they are related in some way -- if one's hard work doesn't pay off, the work feels even harder and harder and one gets tired easier. I suggest video recording yourself and see if you are truly not making progress. Recording can also help you to see how you practice and whether you should adjust certain things that you've been doing to make it easier for you physically.
Well, it is not the same if Mario is 70+ or 17+, is it?
It's hard to make progress when one feels general malaise. They're definitely not orthogonal.
There's a multitude of issues in question, so we can't give much relevant advice without hearing more from the OP. I think almost all good violin teachers teach you to play free of unnecessary tension, even if they have little background in a physical medicine field like Alexander Technique, yoga or physiotherapy. If your life situation is really bad (e.g financial difficulties, lack of appropriate professionals near your home, etc), you could do some careful observation work (e.g videotaping and practicing with a mirror) in attempts to correct some tension issues as a last resort, along with some study of literature on the proper and authentic way of playing the violin free of tension (e.g Simon Fischer, online instruction videos by qualified professionals, etc), as well as injury prevention literature.
Sounds to me like you're just over doing it. Cut back your practice hours considerably. Bad practice is no practice, possibly even worse. Start small and work your way up to the time you want- let your body dictate how quick you increase the time. To make sure your practice is fruitful, list a few things you want to work on during any particular practice and stick to it. Oh, if you're standing, keep your knees bent slightly, it will help get the pressure off your back and encourage blood flow.