Duration
From Pokemon Go Wiki
Duration is measured in ms or milliseconds (1/1000 second). Duration is the entire length of a Move's animation, different moves have different durations. Low duration means that the Moves are fast while high duration means that the Moves are slow. Power Per Second is calculated by dividing Power by Duration (in seconds).
Your Pokemon doesn't take damage during the entire move duration, it only takes damage from the Damage Window.
