Dancers were automatically disqualified if either partner's knees touched the floor.
Dancers were usually given 15 minutes every hour for rest/bathroom use/etc. I cannot imagine how many people must have felt like they were going crazy after such an odd sleeping pattern.
I'm on a history kick lately, and this is the library book (below) I found myself absorbed with this week. This youtube video makes me sad to watch, but it shows actual footage of some of the marathons that were held in the U.S. I couldn't believe the parts where dancing couples would just suddenly FALL DOWN, sometimes toppling over their partners. How horrible! There's also a movie based on the marathons called "They Shoot Horses, Don't They?" starring Jane Fonda. Find the trailer here.