Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Great for problem knees

I have artificial knees and jumping around is not recommended. It can be hard to find a video that will get my cardio up. This one does it well. I enjoyed the presenter. I do this while seated on a fitball. Bouncing while I do it increases the cardio even more, without hurting my knees. Working with a trainer I have determined that I need a larger fitball than the size usually recommended in the tables. If you have bad knees a key thing is to have your knee angle while seated a little more than 90 degrees.I purchased this as an instant video. I can then access it on my smart TV, or my Kindle fire if I'm travelling.