Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Great workout!

Cardio Balance BallThis is a simple but very effective workout program. It builds strength in the lower body plus you get a gentle cardio workout (great sweat without sucking wind). You also get a good workout for the arms and abs. I do wish there was a separate segment for abs. I use eight pounds weights for the arm section but you don't really need them if you don't have any.