I've started venturing from the open position to the movable chord shapes, the E-shape barre chords. These things are hard on the muscles of the hand, especially where the thumb joins the hand. I practiced them for maybe 10 minutes,(F,F#,G) and i was done. Of course, i had already been practicing for an hour anyway, and was ready to go back to the open position. It was a painful cap to a practice session. I wasn't too concerned with how clean they rung out, it's the fingering mechanics and movement i was trying to get used to. Guitarists make those movements look deceptively easy. I'll just keep at it. I was told practicing them on an electric is alot easier, but i'm gonna stay acoustic to build the muscles. Pain is weakness leaving the body!