Well if the impact is strong enough, landing on your fists will still cause significant damage to your wrists. What I always tell people is to make a X with your arms over your chest. And if you need to fall face first, just land on your chest.
But fists are definitely better than using hands/palms. I have a torn UCL in my left thumb because I landed on it.
yeah, i was thinking about falling up hill on my toe edge. if I catch a toe edge and am flung down the fall line i just try and penguin slide it out. you have to much torque in your body being flung down hill to safely prevent a broken limb. if you can just get into the stance of sliding head first into home base, then it should absorb more of the impact.
cross your arms against your chest if falling forwards, crash on your back if falling backwards. Always keep your head away from landing first. Never have any loose limbs flailing before you hit. Man up and suck it up.