Never having been forced to wear skin-tight spandex, I've always wondered... specifically what was it about the S1 & S2 uniforms that caused back pain for the actors? Supposedly that was a common complaint that was alleviated with the S3 uniforms. I can't understand how clothing alone can cause back pain (unless it's really heavy or something like that).
I read somewhere (I think it was an unofficial Partick Stewart bio) that those S1&2 uniforms were too small to keep them always smooth on bodies. Now put on something tight, a size or two too small and wear for 10 hours staight, everyday for two years. I'm not sure it makes you get a back pain, but surely can become horribly uncomfortable and unbarable after some time.