Take the fat and carbs that you would have eaten to power that exercise, and burn them directly in a heat engine, skipping all the biology.
You could try to somehow attach the generator directly to the pedals/crank, that way you won't lose energy to the chain and the bearings on the rear wheel.
It's probably not a meaningful improvement if the bike is well-kept and the rear wheel is lifted from the ground.
Yes, this is exactly what I was thinking. thanks.
Now that all races and events are collapsing under Covid, we could hook in pro cyclist and pay them to cycle. Win win situation