Clearly, Lundgren needs to get his movements down so that what he’s doing looks more like swimming and less like floating in the movie.
While we don’t necessarily expect to see a great deal of underwater material from Aquaman in Justice League, in the Aquaman movie we would expect most of the film to take place underwater.
In the video, posted to Twitter, we see Dolph Lundgren, who will be playing King Nereus in Aquaman, hooked up to a massive rig so that can be hung in midair.
With the help of the rig and two other people he can be pushed through the air, in what will turn into water thanks to blue screen effects in the final film.