I have been experimenting with downhill ever since reading about fell runners - allow me a hero worship moment........
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Ok I am back, and am now solidly in the camp of 'going for it' downhill. I find the easiest thing to do is to just relax into it, lean forward and go as fast as gravity wants me to go. It seems to put much less strain on the quads and calfs.
The difficult bit is to not overstride short fast steps until you get to the bottom otherwise you get a really accentuated heel strike which spoils the rhythm and can be a bit sore.
It's easy on roads but cross country can be fun and sometimes I completely run out of 'bottle' . However it isn't half exhilarating charging through the country side like that.