Replacing a vanilla power attack with another vanilla power attack

[zj14]

So there's this forward power attack for one handed melee I've seen only legionnaires do. Is it possible to swap this with the forward power attack for one handed melee? Can anyone atleast teach me how?

The animation is at 0:58

https://www.youtube.com/watch?v=yOecC2mi8SU&t=2s

 

or the first attack animation at 0:39

https://www.youtube.com/watch?v=WQGZsZxK6fw