My hula hoop is broken

Several years ago, I strode confidentally into the local Sports Authority, armed with resolve to purchase a stylin' elliptical machine. After gulping at the prices (and the knowledge that pavement is free), I left the store, the proud new owner of a yellow-striped hula hoop. The timeless circle, I reasoned, would surely provide a workout as well. AND, it was only $2.99. Bargain! Well, it's sat in my garage for lo these many years until I dragged it out today.

I was more than a little disconcerted to find that I couldn't keep it from slipping down to my knees or from spinning beyond a puny three revolutions. I'm telling you, there must be some malfunction! I swear I used to be rather talented in that arena in my junior high gym class. Or was it grade school? I'll have to test out another hoop for more concrete data.