Stormtroopers were the infantry of the Empire. They evolved from the Clonetroopers that fought in the Clone Wars, and became the face of the new dictatorship. There were several specialized versions of the Stormtroopers, including Sandtroopers, Snowtroopers, and Biker Scouts.
Clumsy?Yes, Stormtroopers were clumsy. They'd fall down just trying to stand up. They bumped into walls and low hanging doors. They slipped in the mud, and they fell off ledges. It almost seems like the Stormtroopers were actually cloned from Jarjar Binks.