Exporting animations is causing them to behave

[Loverssee4659]

English is generated by machine translation. Please forgive any rude expressions.
Let me ask you a question.

ttps://www.youtube.com/watch?v=-mRqaD20cv8
I exported the WW animation to blender 2.76 based on this video, but the behavior of the upper body in the first half of the animation is strange. It is woozy and rough.
Also, the speed of the animation is very slow. I added the animation without fixing the above problem and it actually slowed down, so it is probably not a blender settings issue.
I also tried loading in blender 3.61, but the result was the same.

What should I do?