Is it possible to fall off the trainer?

Not a roller trainer, a rim drive trainer?

Why yes, yes it is. Not to worry, Brent's project car (1964 Chevy Nova) managed to catch me although since the door is not currently installed on the car, I almost fell inside the car.

How did I fall off the trainer you ask? Well let me just tell you how. I was doing my usual Spinerval work out and was out of the saddle sprinting in my Tour de France time trial and my minute man was just ahead of me when all of the sudden the back wheel comes out of the trainer and I start falling to the left. Yes the left, the side where I have one good ankle. Evidently, the mechanism that holds the bike in place had come loose and all that sprinting I was doing was the final straw.

Can you imagine less than one week away from getting the air cast off and I break the other ankle?

I think I would lose my mind.