Yes, the tens!
All the chiropractors use them as well as PT technicians. Usually they are used to loosen up your muscles along with a hot or cold pack prior to lumbar adjustments or after PT where they don’t want a specific area to tighten up.
I was real close to shelling out and buying one last fall. I realized the effect in could have in keeping nerve chanells open. a real good one with lots of different setting can set you back a few bucks. you can Pulse them and set them for continuous stimulation. Turn it up high enough and body parts start floppin and jerkin.