Once again, y'all are awesome. Great posts. As I wrote earlier, years ago the dr. found a Baker's cyst (going down stairs killed!)and told me time was the cure, which it was (took a very, very looooooong time, but got better). I had the behind-knee stuff then, too (might've been connected to they cyst?) but that went away in a few days . What's up now could be a mild reccurrence of the cyst or it's a stress injury - as described, it only happens after consecutive days of skiing, and in more challenging conditions, and is better with rest in a week or two. Since it happens only occasionally (the 1st time in a couple of years now - thot I was over it), and self-improves, I am resisting the dr. but would love to know how to prevent it - and keep skiing! I wonder if I am doing something wrong technique-wise that pulls, hyperextends, twists that leg more. My take partly is I'm over-skiing for my strength (can't resist going out there) so need to work on those hamstrings, quads, and calves. And, I ordered the CW-X pro tights and will try the hyaluronic acid tabs. Will report back. All your posts are so appreciated. :D MSL, yep, the knee is an amazing, important structure!