I let it pass before, but I hate to see this one expand on the basis of an incorrect observation. The body is *not* a fluid. It may be largely water, but water is a fluid and the fluid within a body is compartmentalized mainly into a great number of cells containing fluid/water. The body may, to a limited extent, resemble a non-Newtonian fluid but it is not a fluid. The cornstarch-in-suspension is a consistent fluid; the body is not. I.e., the statements describing the body as a non-Newtonian fluid and the attendant shears seem to flounder a bit.
That being said, the body can admittedly do some funky tricks with fluid pressure. I don't recommend the one shown in this video, but there are some clues in it. This type of training is considered to be "hard qigong" training/conditioning. But remember that someone related an anecdote on this forum about 4-5 years ago about something similar that Tohei did with his arm: