Some people jog, play racquetball, bicycle. Ski racers run up and down hills carrying ski poles. Then they get serious and start jumping side to side over boxes or a pile of pillows.
There are countless approaches to getting in shape for skiing. The one that's right for you is probably the one you're likely to follow, not the one you wish you would. After all, a brisk walk a few times a week is a lot better than daily intentions of full-scale workouts that rarely take place.
Here are a few simple exercises you can do at home without equipment. Start slowly; be consistent; and gradually increase the intensity of the workouts. Remember to start with stretching exercises, stretching the backs of the thighs and calves in particular.
Use a step to raise and lower yourself repeatedly on one foot. Switch to the other leg for an equal number of repetitions. Jumps of nearly all kinds are helpful for skiing - side to side, one-foot, ''spread eagles.'' The US Ski Team has one called a hexagonal jump, and it's done over six 20-inch lengths of polyvinyl chloride pipe, each of varying height (6 to 20 inches). Trainers say that a good recreational skier can complete the hexagon in 20 seconds. I presume they mean jumping.
The ''wall chair'' is a famous one for parties and masochists. With feet about 12 inches from a wall, sit with back straight against the wall and upper legs parallel with the floor. Hold for 30 seconds (or until you yell ''uncle'') and repeat.
Bent-leg sit-ups are good, although skiers often opt for the isometric version. Lying on your back with knees fully bent and feet flat on the floor, slowly raise head and shoulders until your back is rounded. Tighten the abdomen for a couple of seconds, release, lower, and repeat.
Serious cross-country skiers go in for roller-skiing before the snow flies. But climbing hills with those ski poles should help many citizen racers.