How are you defining efficiency here? Is walking really more efficient than cycling? I would put walking as the least efficient manual powered methods mentioned.
Aside: I used to unicycle to work, and I have to say that it was both fantastic and much faster than walking while on a 27.5" wheel.
Aside: I used to unicycle to work, and I have to say that it was both fantastic and much faster than walking while on a 27.5" wheel.