Well, I just pulled a muscle I think. Or two. Yeah, I think two.
Well, I guess experience is a good thing. Now I can tell people this: Don't sit around by a computer for ages, get up suddenly and take a quick walk for half an hour in -25C and then sit still again for six hours, only to suddenly get up once again and walk all the way back in -25C. Especially if you don't have at least three layers of clothing around your legs. Muscles hate being cold. Muscles hate having to suddenly become active without warmup. They also hate having to suddenly stop moving without a nice stretching session. Did I mention how much they hate being cold?
If it doesn't get warmer within a week or two, I'm seriously going to have to start doing warmup exercises before going to school... I've never pulled a muscle in my whole life until now, and suddenly I've done it three times this year because of the damn cold.