After all this time, it's funny to see that they never did fix how unresponsive the Werewolf Sprinting Power Attack is. I remember the first time i played Skyrim was on my friend's XBox 360 the first week of release, and half the damn time you'd try to do a Sprinting Power Attack while in Werewolf Form, it wouldn't go off. All the years that i played Skyrim on my PC, it did the same. I'm back to playing Skyrim with a new character, and the Werewolf Sprinting Power Attack still only goes off about half the time, if that. A real pain in the ass. Nothing quite like Sprinting at a Elder Giant Berserker (mod), getting ready to do the Sprinting Power Attack to knock his ass on the ground, only to have the game not respond at all to me hitting the left mouse button while Sprinting, and ending up with a giant axe planted in my face.

There any mods or anything that fix this persistent annoyance?

Are you giving yourself enough room to get into full sprint? I actually didn't have this problem in Legendary Edition and could do a sprinting power attack and one or two strides, but in SSE my character winds up doing a regular forward power attack instead of a sprinting power attack because getting into full sprint is slower in SSE for some reason. Plus I'm not even using any mods. I'm wondering if this has something to do with sprinting being a toggle instead of stopping as soon as you let go of the sprint button.

I have no idea of any fixes for it unfortunately.

It's weird. I can be sprinting for a good long distance, hit the left mouse button, and absolutely nothing happens, and i can't perform the sprinting power attack for the entire duration of that sprint. Or i can just begin sprinting and hit the left mouse button like a quarter second into the sprint animation, and sometimes it'll initiate the sprinting power attack, other times it doesn't (it's almost as if there's a specific frame of the animation that you have to hit the button to do a sprinting power attack, otherwise it fails). If it does initiate the sprinting power attack, then it'll consistently initiate the sprinting power attack every time i hit the left mouse button for the duration of that sprint.

It makes it a real pain in the ass. I can sprint at someone, do a sprinting power attack and knock them on the ground, and i'll stop sprinting for a moment to turn around and aim myself at them again (turning around while in Werewolf sprint is a pain, since they have such wide turns), start sprinting at them and try to do another sprinting power attack, and it'll completely fail to go off, so i just run right past them again as they're getting back up.