Hhm, I can be mistaken, but ripped muscles do not work, do they?
Anyway, while it is true that muscles can rip and then regrow it is not necessary to destroy/damage them to make them work better, which is the aim of exercise or items that apply electricity to your muscles.
You normally do not damage the muscles in order to train them, that would be nonesense, no muscles rip just because I lift my arm, yet if I do it often enough, the muscles I use while lifting my arms are trained. That means that the body redirects more blood and oxygen to the muscles, which, combined with the nutritiants stored in the muscles, is used to create ATP, which ultimately powers the muscles. After a while, most of the reserves are burnt away, and (damn, I do not know the correct term on English... I really do not know the translation, suffice to say that it is acid), the result is a felt pain. It means that your muscles are overused, and at that point it would be wise to stop. If you ignore that pain, the muscles can be damaged, and will be useless for a lot longer.
If you relax your muscles then, the body tries to prepare for the next time the muscles will be used to this extend, so more protein (and some other nutritiants) will be stored in the muscles, giving them more energy but also making them bigger. This will not only strenghten the muscles in your arm (or whatever you trained), but also your heart or your... damn, another word I do not know, whatever makes you able to breathe, since those muscles will also be prepared.
Anyway, all you need to do in order to motivate your body is contracting your muscles, and this can be archieved by electricity just as well as with normal workout.
But the way to get stronger is not breaking apart your muscle tissue...
In adults, increased strength and muscle mass comes about through an increase in the thickness of the individual fibers and increase in the amount of connective tissue. In the mouse, at least, fibers increase in size by attracting more myoblasts to fuse with them. The fibers attract more myoblasts by releasing the cytokine interleukin 4 (IL-4). Anything that lowers the level of myostatin also leads to an increase in fiber size.
Interesting sites on muscles and the way they work:
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Muscles.html
http://health.howstuffworks.com/muscle.htm