This is in reference to the original walking animation that was used when the game was released. It was a casual sort of saunter, but it was very slow. Then, there was the fast-walk, which Geralt would use when moving at a "brisk pace". Then, the jog that was the default movement speed in outdoor locations. And the sprint, which would be used to dash.
Now, the slow, cinematic walk has been removed, and moving forward (even with an analog gamepad stick) will make Geralt fast-walk.