AllanC and El Greko said what I was going to mention. The idea of line dancing being a form of exercise routine. I want to add that, here in Australia at least, it followed directly on from the aerobic routines popular in the 1980s. I remember performing at a rural show where we were on the program between an exercise group doing "aerobic dancing" and an identical group doing what they called "line dancing". The costumes and the music were the only difference. It was my first sighting of the latter. I said to my True-love, "Remember this moment! We've just witnessed an evolutionary change!"
Footnote - Please don't make me line-dance. I think I'll be one of those 60 year-old women roaming the streets. Joy