CHICAGO - Before you know it, snow will be falling and the wind-chills will be hovering down below zero. Now is the time to begin thinking about preventing winter sports and cold-related injuries. Dr. Trish Palmer, a sports medicine specialist and family medicine physician at Rush University Medical Center, says most cold-related injuries can be prevented with a little planning, preparation and proper equipment.

One of the most common winter related injuries is due to shoveling snow. "It is vigorous exercise and a big strain on the back that people don't appreciate," says Palmer. "The weight and position are really bad for two parts of your back. A disc could be compressed resulting in a pinched nerve. Also, the muscles in the lower back are small and easily strained."

Palmer suggests preventing problems with good positioning and exercise. When you lift 10 pounds close to your body it exerts 10 pounds of pressure on the back. If you lift that same 10 pounds away from your body, as people often do when shoveling, it is seven times heavier exerting 70 pounds of pressure on the back.

The best advice is don't do it. "Our bodies are not built to shovel snow," says Palmer. "Get a snowblower or pay the neighbor kid to do it for you."

If you insist on shoveling yourself, Palmer suggests you start exercising now. "You need to get in shape and build up those back muscles before the snow falls."

That advice holds true for winter sports as well. Exercising in cold weather places extra demands on the body. If you haven't exercised regularly in months, you are more likely to suffer an injury on the ski slopes or at the ice rink. Palmer, who is also a physician committee member of the United States Ski and Snowboard Association, suggests paying special attention to muscles particular to your chosen sport.

For downhill skiing concentrate on strengthening the muscles of the upper leg, the quadriceps and hamstrings. You want both sets of muscles to be strong or you could expose yourself to injury. According to Palmer a great exercise is the wall sit. Sit against a wall like you are in a chair. Make sure your upper legs are horizontal and your heels are directly beneath your knees. Try three sets of 30 seconds each. Try to hold the position a few seconds longer each time you do the exercise.

If you're hoping to be the next Nancy Kerrigan, or at least stay on your feet while ice skating, Palmer suggests working on strength and balance. "Propreception drills are balance drills that can be done at home to help improve awareness of what your foot is doing while your eyes are closed," says Palmer.

In addition to strengthening the quads and hamstrings, condition the calves and the muscles in the front of the leg. Squats, lunges and calf raises are the most basic exercises for lower body strength. To strengthen ankles, use resistance bands wrapped around the leg of a table and your foot. Flex feet toward your body. Repeat the exercise moving your foot in a clockwise fashion, then move the foot counter-clockwise.

Snowboarding is gaining in popularity and as a result doctors are seeing more wrist and arm injuries, especially for beginners. On an up note, people with knee problems may want to transfer to snowboarding because it may be easier on the knees than skiing.

Once the skating pond freezes and the snow falls, the most important part of protecting yourself during winter activities is being prepared. Warm up before you go outdoors for activities to loosen muscles and expand your lungs to handle the cold air. Exercise and cold induced asthma can be worse in the winter so cover your mouth with a scarf to warm the air coming into your lungs.

Dress warmly in layered clothing, hats, warm socks, and mittens. "Always be aware of frostbite and hypothermia," says Palmer. "During a bad wind-chill, you can get frostbite much more quickly than you may think." Participate in outdoor activities with a partner and check each other for signs of hypothermia, which include shivering, drowsiness and lack of coordination.

Don't forget to drink plenty of water before, during and after your outdoor fun. Dehydration can also occur in the winter months with strenuous activities. Don't drink alcohol, which can restrict blood vessels and increase your risk for hypothermia. Protect your skin from the sun and wind using a sunscreen or sun block. The sun reflects off the snow and is stronger than you think.

Palmer can't stress enough the importance of protective equipment and proper fit. Ensure that your skis, skates, shoes and other equipment fit you correctly. Helmets are a must for skiing, sledding and snowboarding. "You wouldn't allow your child to bicycle without a helmet, why would you allow them to do other high velocity sports without protection?" says Palmer.

And finally, enjoy yourself, but remember to stop before you get fatigued. Most winter related injuries happen in the afternoon as participants tire out.