Last night I got some one legged pedaling in on the rollers.
These are a really good way to work on the roundness of your pedaling. Because you've only got one foot clipped in to the pedals, that leg is forced to exert effort the entire way around the pedal stroke. There's no longer any opportunity for the opposite leg to help smooth out your stroke.
I've known for a long time that if I really wanted to be able to race well again I needed to be able to do these smoothly with my left leg. I wouldn't say it's all there just yet, but I was able to get 45 revolutions in on my left leg at a time. There's still definitely some smoothing out to do, but it's at least encouraging to be able to see the light at the end of the tunnel. I'll continue doing these at least once a week in the hopes that my shin muscles continue to strengthen.
Here's a great video of a guy pedaling with one leg, he just takes it a bit further and also does it with no hands on the bars:
no hands on the rollers