So I am 28 years old, my little daughter who is 9 months old can destroy my stamina in a heartbeat.
Kids have amazing power output, are tireless, and driven like a comet. When they decide something nothing can stop them, yeah sure you can lift them 99 times and put them somewhere safe to play, but of course they want to explore every passage and hole they can find.
They aren't any different from regular full sized human, I wouldn't want somebody to tell me when to sleep, where to go and play.
I the end of the day when I see here smile, and her affection for me, it gives me every strength possible.
In some way she is training me to be healthier and live longer.
KIDS! :D