My technique for running downhill. Not sure why nobody else uses it.
I gallop like a deer and I can go incredibly fast by basically keeping one foot constantly in front and never switching it and hopping down hills. I don't have to take a full step and I always have two feet or no feet on the ground so it's impossible to slip.
https://www.youtube.com/watch?v=UBxvn9yEdlY
https://www.youtube.com/watch?v=A7agNyuN39E