observation: you can only jog so slow. if both feet aren't off the ground, you're walking.

using this definition, jogging slowly is far, far harder than cycling slowly. it's higher impact, harder on muscles, and requires more cardio fitness. your HR is far higher.

I'm not talking about 6 minute miles or sustaining 250w for an hour on your bike. there are people who can ride a century but I bet they can't run a 9 minute mile. they can sit in the saddle and pedal 50 watts for hours upon hours.