Bumping to see if anyone knows what causes this ... in Whistler at the end of Feb, those muscles actually cramped up on me, fully, while I was skiing. It made it hard to turn, to say the least. It happened not after lunch, but after skiing a bit and then riding the Peak 2 Peak gondola (ie, a break in action out of my skis).
At lunch I took off my boots and extended my ankles; seems like dorsiflexion is the culprit.
The funny thing is that since then, it hasn't really happened at all. I think that around the same time this alleviated, I started buckling my instep buckle, as the boots were too tight there to buckle for the past season and a half (without cutting off circulation), but obviously have been packing out.
I'm thinking this is all related, but I don't quite know how? I would like to prevent the cramping in the future ... understatement!