Blown strut or not?

How can I tell if I've blown a strut? My ride quality has greatly degraded and I fear I might have blown one or both of my rears. How can I tell if I have, or if it's my imagination. Also, is their a way to tell which it is without having to take them both off?

if you push down on the corner of your car, it should bounce back to its original spot in one or two bounces, up and down motions. if it returns to a diff. spot, its blown. also on the street, is it bouncy, if it is, might be blown, check for fluid leakage, you can just lookat it through the rim.

Also if you are riding down the road and your car is bouncing uncontrollablely then your shocks/struts are blown.