It doesn't make a lot of sense to spend hundreds, thousands or tens of thousands of dollars on a season of skiing and racing and then start it unprepared. Dryland training is a must, especially in those 4-6 weeks when your skis are waxed, sharpened and you're waiting by the door but snow just doesn't want to come!
Here's a good collection of and dryland training exercises.
Harald Harb has this excellent series on training with a slant board.
Something as simple as doing squats on a balance board will be very helpful. Especially if you do them on one leg only (careful - it may be dangerous for the knee, if you don't know what you're doing). Make sure you at least warm up first!
See Dryland balance training and Ski Fitness for more ideas!
Weight lifting is a great way to get back in shape for the season. If you start two months ahead of time and follow even a simple progression like the Stronglift's 5x5 you will be in great shape at the beginning of the season and throughout.
Strong expert skiing requires some athleticism and strength, to put up with the forces and be able to maintain counter etc.
More reading:
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