Great Inventions - the Bicycle

Apparently, at least according to my mate, the bicycle is the most efficient machine man has ever created. Amazing! Apparently, it even beats the rocket. I asked my friend to define his terms a bit - "like, efficient in terms of turning potential into kinetic energy, or some other measure of efficient?". He kind of went with that. Most probably he realised it was too far into the evening to explain what was in his mind in a way that would make sense to me. I'm not an engineer. There were many people eating curry and drinking lager and of course it's possible he was making it up. I really hope not.