I went over on my ankle on the Corridor Route. Fortunately no damage was done but it made me think. The rock made me put my foot down at an angle. The line of action of the force as shown by the red arrow on the photograph was outside the base area of my foot. This created a resultant moment with the edge of my boot as the pivot. The twisting motion wasn't good for my ligaments and tendons. I was hurrying to catch up at the time so the rate of change of momentum for each footfall was bigger with a bigger resultant force. Hence a bigger resultant moment and more damage. Moral of the story is for me to avoid hurrying and watch where I put my feet!