I once had small electric currents passed through acupuncture needles that were put in my back to relieve pain. The therapist explained that the currents were pulsing my muscles many times over the twenty minutes that the needles were in. That pulsing of the muscle made them tired and so they would relax.
Here is an article about many medical uses of small electric currents from healing wounds to pain relief to cosmetic uses in making skin firmer.
Just bending down to pick something off the floor can be dicey if your back is giving you trouble. You look at that spoon that fell down and think “Is it worth trying to pick it up? Will I be able to straighten out once I bend down?”
When your back is on that edge of going into spasm at any moment, you can help it out by stretching it right where you are. Tilting the pelvis will lengthen the lower back and allow you to keep moving.
Tilting the pelvis as you stand, sit, or lie down will instantly stretch out your lower back and bring relief.
This is especially important for people with slipped discs.
This three minute clip shows you how to tilt your pelvis while standing. Do it sitting or lying down too.