http://www.5min.com/Video/How-To-Play-Bass-Blues-Progressions-2459614 This video shows I IV V progression - but I'm confused. He's playing the notes, but he's playing in different positions. He says "Now we're playing on the root", "Now to the 4th" and he switches positions. So does I IV V mean position?? I think I'm just not getting something simple. I get the I IV V notes of the major scale based on the key - but I don't see how the I IV V progression relates to the position changes in this video. Can someone clarify?