I am surprised by this lack of understanding of proper training. Muscle tissue should always be warmed up before any extreme exercise! Stretching should be done only with properly warm muscles, and is best done after exercising(skiing). Raising your heart rate prior to skiing will also jump start your oxygen delivery to muscles. If you never participated in organized sports with professional coaches, you should read up on proper training techniques. I always try to ride my bicycle for ten minutes, then follow with a series of exercises and stretching before I ski, practice or tournament. And yes, this has become more important to me as I have aged. But I am still skiing! With all the reports of injuries lately, I hope every skier will take the time to warm up then stretch before every set.