Ed,
If that guy is correct, then under certain conditions, the bar is under tension, although the movement of the towers would be very slight.
Other people on this board, though, who are much smarter than me in this area, have said that probably the bar experiences "less compression" at some times than at others. The article in question, which I used to place a lot of stock in, relates only third-party info about "someone" who actually hooked up a strain guage and got a tension reading.
I lean, now, toward believing the guys on this board, who do this stuff for a living. Only way to really know, though, is to get a strain guage.
