I have seen a music video.
It shows the movements of the people in it not in a fluid manner, yet, it does not seem to be a sped up video.
Would it be on topic to ask here how such an effect might have been obtained?
Asking how to achieve a particular visual look in a video would be on topic, however you would need to provide both a written description and preferably a video clip as well that we could look at (or at least something we can look up) for reference to see what you are talking about. As currently described, it isn't really clear what you are talking about. It's also possible it is just a form of dance too. There are some people who can execute very odd looking dance moves.