Shaping Up in Advance for Skiing : Exercise: Skiers can condition themselves for their sport through a program that combines aerobics, anaerobic workouts and calisthenics.

Being in good physical condition helps reduce the chance of injury or accident and makes it easier to improve your skiing skills.

Whatever exercise program you follow, begin with plenty of easy stretching. And if you’re over 35, consult a doctor before beginning any exercise program.

Skiers who want to be in optimum condition should follow a program that combines aerobic and anaerobic workouts with calisthenics. Aerobic exercise builds up the cardiovascular system for better endurance; anaerobic exercise helps oxygen-starved muscles perform well.

For the best results, build your exercise program on a firm aerobic foundation. Swimming, bicycling, hiking or running are all good routes to an improved cardiovascular system.

Runners can help develop ski-specific skills by making frequent turns, by crossing over an imaginary line between their legs with every stride, or by running sideways or backward.

Cycling and swimming are especially worthwhile; both build strength and aerobic conditioning without putting undue stress on joints and ligaments. Mountain biking in particular is a good workout for skiers; it helps build strong leg muscles. To increase your aerobic capacity, aim for workouts of long duration but of only moderate intensity. For noticeable results, plan at least three 20-minute exercise sessions each week.

Anaerobic conditioning is important for skiers, too, otherwise you won’t be able to carve those turns when a long run takes your wind away. Stick to the same exercises recommended for aerobic training, but increase intensity and decrease duration.

Once you’re through with these basics, more esoteric exercises can give leg muscles the same kind of torture a ski slope would.