I just stumbled upon this page:
MoFrames, making movement complexity visible. (Martin Hilpoltsteiner)
If I understood correctly, he is taking the individual images of the person and put them one after the other in a 3D space, then render the view from various angles.
It gives pretty interesting results to grasp volumes used during the action !
Here is a person jumping on a trampoline.
(There are plenty more on the site)