When running after a light skiff of snow fell. All good til about the last 1/2 mile when I hit a hidden patch of ice and did a flip worthy of a 10 from the Russian judge!! Amazingly it didn't hurt....til the next day. Big thing was that I somehow pulled a muscle in my calf. Haven't ran in 2 weeks, walking is ok, slowly on the mend. Moral of this story...getting old sucks, that and pay attention to your surroundings!