Patience. It is a necessary characteristic of an animator. Hence we leave all topics to mature for three hours before replying so that the trait is nurtured.
I'm kidding, there was no one on.
Basically, easing. You need more easing. You also need to look at how people actually move. It would be good if you posted in the beginners section too.
I have now merged these threads. The animations do not need to be given one thread each. Make one thread and update it if you're not going to post in the beginners section.
The ground crack actually made the kick worse, since there's not even close the amount of power involved to make cracking the ground remotely understandable. Just saying, you need a better grasp of physics, forces and all.
He needs to be constantly falling forwards after he lifts his leg up since he's off balance. You need to be trying to move every joint in every frame, otherwise it looks stiff.
You really shouldn't spend your time with stuff like that. Animate walking cycles, running, punches, whatever, just to get a feel for fluid motions, easing and physics. Shit like the shoop da whoop bollocks won't help with any of that.
Also, there's an "Edit post" button that you can use to add stuff to your posts. That's a better choice than double posting.