Instruct: Classify Amazon reviews into positive or negative sentiment
Query: The best back therapy I've found

I have back problems from minor aches to severe nerve pinches, depending on how I sleep and how often I take (or don't take) breaks from my desk job during the day. No matter how my back feels at the end of the day, doing this video ALWAYS makes it feel better. I've found that it's gentle enough to do no matter how much pain I'm in (although obviously you have to modify it when you're really tweaked). Like other users have said, it helps faster than any medication treatment, and it's easier, cheaper, and faster than a massage or other therapy!