I was watching a documentary on Graeme Obree last night, and thought it was interesting that he trained for the hour record with a huge gear to get his legs used to holding that gear for an entire hour. So I figured my commute is flat, why not? So I set my bike to 50x11 and left it there as if it was a single speed. I'm completely cooked, but I feel like it was one of the best workouts I've had in a long time.