Here in Fontainebleau, there are bouldering circuits in the forest set for the level of our three year old. (Seriously. Painted with little pink hearts next to the arrows).
They get used, too. Even for me, climbing pretty hard these days, I'll often run off and do an easy Blue or even easier Orange circuit just for the joy of movement over 40-80 nice problems, few of which would even get a V0 if you translated the grade across.
The difficulty scale goes as far as you want in either direction.
Can we compare difficulty levels with children? They seem to be naturally better at climbing at that age. Faster recovery period and their tendons and ligaments seem to be able to handle their small weights well.
* children are smaller, so holds in general are proportionally larger
* children may have a different lower and upper body ratio (they've got shorter legs than adults), making them better suited for climbing.
* Better flexibility/mobility
* don't have to be (re)taught how to play
* perchance better strength/weight ratio
* relatively fearless
* usually can find a enthusiastic peer group that isn't so centered around competition/jealousy (similar to, "knows how to play")
* A lot of kids I see at the gym have parents that have been climbing half their own lives, so they've got incredible coaching from a trusted source, and an amazing cheerleading section. They'll be climbing most of their lives, if they decided to keep it up.
The only real detriment may be that problems in a gym setting aren't always made for their sized bodies, so some of the moves may be a bit reachy. A children's general creativity could allow them to solve such issues though.
It's as hard as you want it to be.
Here in Fontainebleau, there are bouldering circuits in the forest set for the level of our three year old. (Seriously. Painted with little pink hearts next to the arrows).
They get used, too. Even for me, climbing pretty hard these days, I'll often run off and do an easy Blue or even easier Orange circuit just for the joy of movement over 40-80 nice problems, few of which would even get a V0 if you translated the grade across.
The difficulty scale goes as far as you want in either direction.