I'm not quite sure I understand. The only thing that would tear a muscle, tendon, is involuntary and severe cramping. Stretching is a voluntary action almost always. It is possible to stretch too far and strain and in rare cases tear a muscle or tendon/ligament. You refer to stretching in your sleeping that's what I'm trying to understand.

I'm in very good shape for a 70 y/o, and I will get very bad hamstring cramps when I'm in bed. But those are involuntary.

All the best.

@rgg i’ve gotten those, and there are various ways to resolve the problem that I have found. Initially it started when I was pregnant that at night my legs would wanna stretch and they go into the most painful cramp in the world following the stretch, and that was called a Charlie horse, and it was resolved by either vitamin K or magnesium or both. Also strengthening my muscles during the day. Then later it showed up again as a byproduct of my degenerative disc disease where at night, my body, my legs would wanna stretch, and then they would cramp again. Part of this was damaged from not having back surgery in time to prevent permanent nerve damage. So I consider some of my nerves very dysfunctional. I increased the supplements and I increase the exercise during the day and it seems to go away. Another thing you can do is asked to go to a nerve specialist. They attach a little diagnostic trigger, and they figure out which nerves trigger the dysfunctional reactions. I’ve been to a nerve doctor. I forget what the abbreviation is a couple times and I don’t really like it so much because it can be kind of painful when they trigger the muscle muscles into spasm. But you’ll definitely be able to find out where your problem lay! Definitely a supplement that contains magnesium should be a good help!