Asuka is a Zumba legend- she can be seen featured in all the dvd sets and is known for her beautiful smile, dynamic personality and powerful dancing. She left Zumba to start her own hyperintense fitness class called Kazaxe which veers away from a Latin music emphasis, and is only offered in the DC area (too bad!). You can enjoy her videos on youTube however. Just look up Kazaxe or azukabom.
Asuka recently posted this very informative video for her students about one way to add intensity to their workout.
I really have nothing to add except that I’ve observed sometimes we are so fearful for our joints that we baby all our muscles and don’t challenge them. In many cases, by strengthening the muscles surrounding the joints, we can better protect them. In other words, squats and lunges (with proper form of course) actually help your knees by creating a better support system around them. Don’t be afraid to work those muscles! Let them do what they were meant to do!