I love my twice-a-week Zumba class, but had noticed that about half the time my right knee hurt during or afterward. There are a lot of pivoting motions in both Zumba and other aerobic dance classes and they can cause or worsen knee issues, which my instructor pointed out.  I pulled these on over my zumba shoes and my knee issues were solved.  My instructor now suggests them to new students.  You get three pairs, which should be all you ever need.