Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: Worked for me!

I strained my back helping an aged relative get to her feet from a chair (never again). This time I thought I had really done it to myself. Went to the sports medicine doc affiliated with my GP's group. He ruled out anything like surgery and sent me to PT. The therapist suggested the McKenzie book and started me with the exercises suggested therein. I continued them on my own and after three visits discontinued the PT. Now whenever I screw myself up I do an exercise or two a few times each and I'm back to being myself again. Worked for me!