Originally posted by: kupalmaru
The weapon kinda look dangerous.
When your running really fast, you could accidentaly hurt your self with the blade.

When your running, you move your hand up and down; that's when you can accidentally whack your self.
food for thought:

Kisame vs Asuma

Asuma's weapon hinders him to perform hand seal or it was just coincedence , kakashi arrived during Kisame jutsu