Just play with this yourself. Put your camera on a tripod, and set it to shutter priority mode. Set it for a shutter speed of 1 or 2 seconds, and focus it on something static (like a piano keyboard if you have one!). Let the camera chose the correct aperture for a correct exposure.
Now, stick your hand in the frame and take the shot. While the shutter is open, move your hand around.
What you will see on the photo is the static area of the image is sharp (because it didn't move), but your arm will be ghosted and blurred due to the movement during the long period of time the shutter was open.
In other words, the shutter speed was not fast enough to "freeze the motion" of your hand. This is a very common issue. Often when people complain that their images are not sharp enough you can look and see that they are trying to photograph a running puppy with a shutter speed of 1/15th of a second, when it should be 1/500th kind of thing. In your case, rather than get a shutter speed fast enough to freeze the motion, you want to go the other way and use a shutter speed long enough to create the blur from the motion.
Hope that helps!