Tasers

The whole idea behind a tazer is to lock up those muscles and make the person your stunning unable to move. The pain is just a beneficial side effect of the system. When electricity runs through a muscle, it causes that muscle to contract for every movement you make you are using at least two muscles.When you have something like a tazer sending electricity it's activating all the muscles causing them to work against each other and preventing movement.I would see no reason why the same thing would not happen with a zombie. Studies on the brains of cadavers hours even days after death revealed that small electrical impulses can cause muscle to react and cause movement in the limbs. however, it must be noted that after a time, muscles use up their supply of energy and become locked. This is known as Rigor mortis. that leads into the argument on how it's impossible to have "traditional" zombies, but i'll leave that for another thread.