My sister nearly died from a similar accident. It was a huge flight of really hard stairs and she rode the trike down it. She was probably about three at the time and proceeded to tumble down the steps and when she landed her head was bleeding through her eye. She had to be airlifted to a hospital while a couple firemen gave my brother, sister, and I a ride in the firetruck to console us. It was really quite serious, and we are lucky to still have her with us.
I can't really remember when I was in the most pain, but falling out of a tree and breaking my arm was pretty bad.