How to rotate object without changing length?

[StickFights44]

Hi, I was wondering how you animate, let's say an arrow, to rotate. Every time I do this, as it is rotating, it gets much shorter and changes size before returning to it's original size. Why does it do this, and is there anyway to prevent it?

[slowtiger]

Rotate the layer, not the points.

[StickFights44]

I feel so stupid now! Haha thank you!