Does anyone else have this problem?

[rainmaker]

I'm finding that my InterraWear shirts are doing the GI creep during the game. I have to keep pulling them down. They don't do it if I pull them tight down into the bike shorts, but then arm movement is restricted. In the past I've always pulled my shirt up just a little to blouse above the waistband. It wasn't any problem last year. Is this an issue because the shirts are getting old?!? Any hints, folks?