Specific and careful preparation pays off. Click here to visit their site. You will be coming to grips with gravity and a slippery surface, and will use muscles you didn't know you had. There is always the risk of pulling muscles or twisting joints if you are not prepared. You should leave plenty of time to improve your fitness before you travel - you are probably not as fit as you think.
Injury prevention is the major reason for getting fit to ski.
Flexible muscles will help prevent pulls and tears. Strong muscles support the joints, especially the knees and shoulders which are vulnerable when skiing. An all-round exercise programme which includes the above fitness factors should be started at least 6 weeks before going skiing. Build up to working out every other day. If you have left it too late, never mind.