Nope, they were professional dancers who were in well-regarded troupes.
For all the people who are saying this should be bigger than it is, I just thought that I’d mention that it is in Eastern Asia. Japan, China, and Russia are all heavily interested in the sport and you see it about with decent frequency.
I suspect it hasn’t/won’t catch on in the US because it’s sort of an overly “girly” sport. But maybe during the 50’s it was a sport we were in?
Well, you’ll have to excuse me if I take my ten years of experience as a gymnast over your peripheral experience with someone you knew. If you break your back doing a backbend you either did something wrong, or possibly had some unusual condition with fragile bones. Since you are saying they were dancers, anorexia wouldn’t suprise me. You can’t break your back doing a backbend unless somethings wrong. Just look at the girl in the video. I guarantee, she’s fine.
I was a bit mystified by all the people who hadn’t seen this kind of thing before until I remembered, rhythmic gymnastics is extremely popular in Japan so it gets on TV here pretty frequently. And as much as it makes me look like a sexist pig for saying it, I prefer watching this over regular gymnastics because the athletes look like adult women instead of pre-pubescent children.
Incidentally, my wife did this sport as a teen. Caught me off guard one time when we were playing with our son and out of nowhere she picked up his inflatable ball and did that “fling it into the air, jump, do a somersault and catch it behind your back” trick.
Does it count if you jump through the hoop while holding the ball?
They’ve been showing Rhythmic Gymnastics since the 1984 Summer Olympics in Los Angeles. I believe that’s when I first saw it. It’s the main thing I watch during the Summer Olympics. True though, it’s usually on at weird times and doesn’t get the publicity that regular gymnastics does, but it is shown, and there are Americans who compete.
I once heard a commentator who had been a rhythmic gymnast say that though the Olympic-class competitors make it look really easy, it’s not, at all. Obviously, but one of the things she pointed out that I thought was fascinating was that they’re supposed to make the ball look like it’s magnetic, when of course, it isn’t. This girl is a perfect example of doing it very right.
Rhythmic gymnastics were aired for the 2008 China Olympics, on NBC and in prime time. It was in the final days of the games, so most folks probably missed 'em. Some really neat ribbon routines.
So, you want to see incredible things with balls? Well, things that are safe to view at work, that is?
This guy impresses the heck out of me. His name is Michael Moschen (humorously enough, pronounced like “motion”), and he does a number of unusual things like this. Link goes to a vid of him “juggling” rubber balls by bouncing them in a giant triangle.
It’s called “showing off” where I come from! 
Seriously though, I’ve always been in awe of the control a good gymnast has over their mind and body.
He also did the crystal ball work in Labyrinth. Here is a video of some of that. (please ignore the fact that he is nearly nekkid)
Ignore it, my ass! That guy has a very nice build on him–any other perv girls thinking it would be fun to sit on his hands and say “Juggle me, baybee?” 
Well that opening shot is certainly from an interesting perspective…
Ga DAM I hate YouTube*! They should call it YouTimeSucker. Think of all the things I could have been doing instead of sitting here watching Rhythmic Gymnasts and phenomenal jugglers with my mouth open and my eyes wide in wonder and awe and disbelief.
I could have been, geez, cleaning house or learning how to juggle or something.
I had never heard of Michael Moschen, but oh…my…god!
*not really, of course. YouTube is the greatest invention since the Internet itself.
I agree with most postings on this thread – this is very interesting.
And yet, whenever there’s some thread about what Olympic sports are “stupid”, or should be “eliminated”, rhythmic gymnastics is always among the first to be mentioned.
Just shows you can’t please everybody.
Ed
I want to sex her. Very bad.
People (guys) used to make fun of me for watching rhythmic gymnastics. That lasts until they see it for themselves. Amazingly hot.
And they’re all 18 in my mind…
The tags on that video are bizarre.
I read those tags too thinking that the vid may be a whoosh.
The thing that always strikes me with rhythmic as opposed to traditional gymnastics is how much grace is still in it. Its the difference between ice skating and ice dancing - the traditional sports have become so athletic that much of the grace has been removed from them - to be replaced by athletic flips or jumps.
Yea, I’m not a big fan of grace in gymnastics. I hate the dancing portion of womens floor excersize. I want bigger tricks with more flips and more twists and extra danger. That’s probably why I much prefer watching men’s gymnastics. The routine has to be smooth and connected, but that’s all. I’m really glad that they changed the scoring from the early nineties to include difficulty points.
Gorgeous Elena Lev from Cirque du Soliel’s show Alegria. (Some of the same moves as the gymnast in the OP but with hula hoops.)
And Victor Kee doing a ball routine from Cirque’s Dralion. If you liked the girl in the OP, you’ll be blown away by this guy. (Nothing against the OP’s gymnast, btw, this guy is obviously a very highly trained pro.)
The singers are fabulous too. Francesca Gagnon in the hoops video and Erik Karol (yep, he’s a man) in white above the arch behind the juggler.