I had my only bike on my a new cyclops fluid trainer all winter. Used the trainer specific skewer for all rides except trying it out at the shop, and the first one at home as I couldn't find the right skewer that day. Used the trainer about 10 hours a week from late October - now.

I noticed problems shifting in the rear, and could see the rear wheel moving in such a way that made me think the rear wheel was out of true. Took the bike of the trainer and went to get the wheel trued to discover that the wheel was in fine but that the free-hub body had worked loose.

No bigee, the shop fixed it and I'm good to go. The only explanation they could give me was "trainer use". Nothing more specific than that.

But the weather has be el crappo the last little while and I need to ride - I'm worried about putting this bike back on the trainer.

Any ideas why this happened and / or how to stop it happening in the future?

Bike suffered no falls or drops during the winter or other types of obvious trauma this winter.