Instruct: Classify Amazon reviews into positive or negative sentiment
Query: What a workout juggling these balls!

Perfect size to juggle with. Bought 3 to work with. It is quite a workout keeping these ball going. Have dropped them many times now...no damage to the balls themselves. Its a total body workout just to juggle the 3 balls for 2 minutes. Someday I hope to get up to the 10 pounders!