Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Works great

I had been using these in size large for a long time and worked great.This time I decided to buy medium (even though it is a little small forme it gives better support). I have problems with both of my knees and as long asI wear these when I do any kind of exercise my knees do not bother me at all.I highly recommend them if you have knee problems.Amazon's price is much much lower than Sports Authority.