I don't know man, yesterday I rode with a tiny 70-year old all the way just before the climb at Les Matelles to Jacou, a distance of about 30 km at 30.0 km/h, and with up to 50 km/h crosswinds (they were stronger earlier in the day), and we spent most of the time chatting. I can tell you that it was easier for him than for me. By tiny I mean that from the back he looked like a skinny boy!

As you may imagine, due to his small size, he was strong on the climbs, but for instance he dropped me during a rolling hill after St-Croix-de-Quintillargues, we were casually doing about 29 km/h on a false flat in the crosswinds, sth like 0.8 to 1.0%, and as the road started pitching down he decided to attack yet another cyclist in front of us, I was too slow with the down-tube shifters, crosswinds got between the wheels, game over, I caught up with him a couple of kms later and he was still fresh as a daisy.

He had a running background, but it goes to show that even tiny engines can be trained to produce quite a bit of power.