I call these the "high arch - spring dis-lodging - self frame impacting - auto-imploding" trailing arms.
I think they are supposed to be straight. That or they should have a very slight bend in them
What actually happened was I was trying to climb a foot and a half tall tree stump and some how these decided to give out and ram my tires into my wheel wells. It was the most pathetic trail breakage I have ever seen. I do not even see how an engineer let this design make it out onto the street.
I replaced them with some other arms I had off of an 89 which are make from tubing and not round bar and seem to be much more sturdy than these.