I go to a Cardio Drumming class 3 times a week an hour long . I love it . I have sore knees and a hip that hurts all the time . but when I am done I feel so much better . we do 30 min of drumming on the exercise balls and then we do floor exercise and then back on the balls for some fun bouncing with the music . Everything is done with music and it is so much fun you don't even feel like your working out . I love it..