I had a very severe back injury at age 17 (5 years ago) and only recovered to about 85% range of motion.

Now that that's out of the way, I absolutely love the Prius seats. For my body size and shape they're the perfect fit. Now I'm not really big or really tiny, just average, middle of the road 20something girl. I have never had back pain driving in this car even on longer trips. And this is coming from someone who spent $2000 on a Tempur Pedic mattress just so I could get some sleep because nothing else worked.