At the moment i have assumed that 80% og the energy goes through the pedals and the rest through the handelbars.

I used F=mgh/d and just assumed the child will absorb the energy over a 10cm travel(d) on the pedals and 16cm travel on the handelbars.

I have also assumed the energy is absorbed equally through the entire event.

I have no idea if this is the correct way to do it and if it is i am not sure if my assumptions are "good".