We used to have a 20 ft chain in the front yard for our dog to go out.  He would go as far as he could, then run in a half circle to the other end... straight into one of those large electrical boxes.  He did this daily.

Then we fenced in the back yard so he'd have room to run.  He also refuses to be back there unless we stay with him.  He's sweet as can be though and great with my kids.