# Avoid motion blur in rendering?

I am re-rendering the Blender open-source Sintel movie. In particular, I am rendering (as a series of .png images) a scene where Sintel (the main character) is running.

I am getting motion blur in my .png output, but there isn't any blur in the "Render Result" window of Blender GUI. Why do I have this motion blur, and how can I remove it?

I tried increasing the frame rate, but it doesn't help.