No body jarring. It vibrates only my lungs. It’s a hand held device about the size of a hair dryer, even looks kind of like one. (You’re not old enough to picture the old hoods ladies sat under in the salons, are you?😉) you plug it into a rechargeable box the size of two large decks of cards. You choose a tone pattern, put the mouthpiece in, hit go. It sends tones into your lungs that vibrate like a deep bass feels when it’s loud. I’m sitting at a table now, typing this with one hand, holding the Vibralungin my mouth with my other hand. Takes 10 minutes. Then I’ll do my nebulizing with 7% saline. I finally figured out how to attach my Aerobike to the nebulizer so now I get more lung vibration with that. NIH studies show results of Vibralung equal to vest. I’m sorry your back is hurting. Maybe this would help.