To a degree, although it looks “bend their spine quite deep and forward”.. the ‘fwd’ at the top should also have a ‘fwd’-up at the bottom.. thus it is called a “C-curve” (ie shaped like a C when looked at from the side…. and recall 70%… many have seen them (the instructor-demoing) do the move, and then try and make it look that way, but:
It might be that they are showing so it can be seen, more obvious- it can be more gentle a curve in practice- also they have been working the neigung loosening for a while.. to try and “make” your spine bend, cuz it was shown that way (as many have) is forcing and adding tension…
see how you spine releases.. over time– dont’ bend the head fwd and down in such a way that it bend up the chest, nor tugs down back.. but that opens up “spongey-qual”
Just one viewpt- best of luck