you're fine. HOWEVER, riding a fixed gear on a trainer can be another story. My Track Pro has a bit of chain suck (really only through the paint) on the chain stay because the chainring cuts so close to the stay... this is from just having it up on the trainer once when I sent my bike home a week early for a race and I had to get in some training miles leading up to it. It's going to flex more since it's holding the rear in one place, but for the most part, no big deal, or else you'd be seeing a lot more people warning against the dangers of the trainer!