My achilles decided yesterday that walking up stairs was a bad idea. Nothing in particular brought it on, I hadn't been doing anything strenuous on the day in question, I'd actually been sitting down all morning, and it just started aching. I'm walking a lot better now, and stairs aren't a problem, but this evening I wasn't able to jog on it at all, in rugby boots or in runners.

Any thoughts on what the problem could be? nyone have anything similar happen to them? Can/should I still ride? It feels like the impact of foot-planting when running is the problem there, rather than motion.