For the last five years, I have worked in the medical tent at the end of the Marine Corps Marathon, treating runners whose bodies have paid a price for pounding feet against pavement for three hours or longer to complete the 26 miles.

If you have trained carefully, the odds are substantially against suffering serious injury. If past years are any guide, more than 60 percent of the 10,000 to 12,000 starting at the Iwo Jima Memorial Sunday morning will be first-time marathoners, and some 85 percent will finish the distance with body and spirit intact. Of the some 600 documented medical problems last year, about half were blisters, another 128 were heat/coldness injuries, 36 involved dehydration and 79 simple exhaustion.

If you do have an injury, medical facilities for the Ninth Annual Marine Corps Marathon will be formidable: two fully equipped field hospitals, medical aid stations at each water stop every three miles along the route, over 300 medical support personnel . . . and 2,500 pounds of ice.

Like all races, the Marine Corps Marathon -- the nation's second largest -- has its share of traps for the unwary. Hains Point (miles 17 through 21) can be abruptly cold and windy -- particularly after 18-plus miles of running -- and presents a risk of hypothermia. Washington weather can be erratic, with unexpected hot or cold spells or rain. Also, with 10,000 runners crowded together the first several miles, it is easy to trip, fall or twist an ankle.

On the other hand, the Marine Corps race course is almost totally flat, except for that minor hill just before the 26-mile marker. (Didn't anyone tell you about that?)

The goal for any marathoner, of course, is to avoid needing the medical facilities at all. Here are some last-minute tips that could help:

Taper Off: Proper marathon training must start several months before. It's too late now to start pouring on eleventh-hour training miles; you'll burn yourself out before the race even begins. The final days should be spent resting, or "tapering off" your regular regimen. Take a hot bath the night before and get a good night's sleep.

But even if you have trained properly, you may, at some point after about 18 miles, "hit the wall" when your body depletes its supply of energy-giving glycogen. Cheer up, even Alberto Salazar suffers during the last six miles. (We're not so sure about Joan Benoit.)

Conceptualize the Race: Every marathoner should have a strategy, a preconceived idea of how fast -- or slow -- to run the race, and how to deal with those painful late miles. The midway point in a marathon, both physically and emotionally, is the 20-mile marker. Plan to run the opening miles at a leisurely pace, saving strength for the end. A general rule of thumb: For the first 13 miles, avoid speeding up. For the last 13, avoid slowing down.

Consume Carbohydrates: Carbohydrate loading is a hedonist's fantasy come true. Carbohydrates -- found in such foods as pastries, pizza, ice cream, pasta, bread and rice -- are converted by the body into glycogen, the basic fuel for muscle exertion. Runners "hit the wall" when the glycogen in their muscles becomes depleted, and their bodies must start burning fat for fuel.

The day before the race, eat generously, capping off Saturday lunch or dinner with the meal of your dreams: mountains of spaghetti, German chocolate cake, seconds on dessert and plenty of liquids. (Beer can be dehydrating for some people; if in doubt, drink water.)

Conversely, try to run the race itself on an empty stomach. Keep Sunday breakfast light -- fruit juice and toast -- and finish eating at least two to three hours before the starting gun. If coffee upsets your stomach, skip it.

Drink Fluids: Dehydration, the severe loss of body fluids, is a serious danger to all runners, and especially marathoners. Don't skip water stops, even if you don't feel thirsty. The extra 10 seconds will not ruin your finishing time. Also, drink plenty of water before the marathon starts, and after it ends. I recommend drinking at least eight glasses of water daily starting mid-week before the marathon.

Late in the race, "body punch" will be served along with water. "Body punch," like Gatorade or other "sports drinks," contains certain chemicals -- "electrolytes" -- lost through perspiration during a long run. Some people find it improves their performance, others do not. But whether you drink water or "body punch," drink something at every stop.

If you feel dehydrated, stay away from beer right after the race; alcohol can aggravate dehydration instead of help it.

Respect Your Feet: Avoiding blisters is usually simple: Wear running shoes that are comfortable, well-fitting and broken in. If the shoes are old, make sure the heel is still balanced and padding is adequate. Best are running shoes with 200 to 300 miles on the odometer.

Before the race, apply a generous lining of Vaseline to your feet and around the toes, especially on calluses or "hot spots." The Vaseline will lessen the friction and help prevent blisters. If you have trained with other shoe inserts, don't stop now. The marathon is no time to experiment.

If you're troubled by nagging health problems, ask a sports doctor whether you should attempt the race at all, or visit the Marine Corps Marathon exposition and symposia at the Sheraton National Hotel. Panels of doctors will discuss injury-related issues at 7 p.m. tomorrow and 2 p.m. Saturday.

Listen to Weather Forecasts: Hypothermia (loss of body heat) and hyperthermia (overloading of body heat) can prevent you from finishing the race, or worse. The most notorious form of hyperthermia is heat stroke, where the body's cooling system actually shuts down and sweating stops, which can be fatal.

If the air is chilly, wear extra thin layers of loose, disposable clothing: a wool hat, extra T-shirt or garden gloves that can be thrown away along the route. Consider saving some protection for Hains Point.

If the day is hot or humid, keep your body moist by pouring water on your forehead at the water stops. A white painters hat (especially for bald men) and loose-fitting mesh tank top also can help keep you cool. Be aware of the symptoms of heat stress: dizziness, weariness, cramps.

Listen to Your Body: There is a difference between pain (which you are supposed to feel in a marathon), and injury. Often a tight muscle, cramp or soreness will work itself out as the miles progress. Deciding whether an injury or pain is serious enough to quit the race can be difficult. Nobody wants to drop out after months of training and bragging to friends about the big day. But miles of running cause tremendous wear and tear on the body. A small heel bruise at 15 miles can grow into an ugly stress fracture by the end.

If you experience pain or minor injury during the race, particularly in the knee, hip, ankle or foot, stop at the next aid station and massage the injury with ice. Ask a medical staffer to take a look. If the pain subsides, try running again at a conservative pace. If the pain returns, stop and ice it again. If it persists -- sorry, it's off to the showers.

The same is true with muscle cramps, "stitches" and minor backaches. Stop along the route and stretch, then try running again.

While runners may generally decide for themselves whether or not to stop running, the medical staff is authorized to pull people from the race in serious cases. If a doctor tells you to call it quits, don't argue. Wounded pride heals a lot faster than an injured body. The Marines will provide three "straggler vans" to fetch you back to the start/finish area with time to manufacture excuses for friends and family.

Stretch and Warm Up: Take time before the race to stretch your muscles thoroughly. But don't waste energy before the race by jogging around the starting line or doing jumping jacks. Save it for the marathon.

Examine Your Motives: There are two goals in any marathon. One is to finish. The other is to survive, to walk away from the finish line injury-free. In marathoning, perhaps more than any other sport, the line can be blurred. To endure the late miles beyond "the wall," a runner must draw upon deep inner powers of stamina, determination and sheer stubbornness.

But just as there is beauty and nobility in this human drama, it also has the opposite potential. Remember Gabriela Andersen-Schiess, the Swiss marathoner who entered the Olympic Stadium in Los Angeles, the left side of her body paralyzed? Yes, she finished the race in a courageous effort, but she also risked serious permanent injury and possibly brain damage.

Remind yourself of the reasons most people run: for fun, health and pleasure, not for martyrdom.

Beyond all of these caveats, running the marathon is an uplifting, exhilarating experience. Crossing that finish line is a rare stunning moment in life, a pure and uncomplicated feeling of victory and satisfaction. Gliding through the scenic streets of Washington on a brisk autumn day with 10,000 of your nearest and dearest friends, the marching bands, people cheering from the sidewalks, the Marines handing you water, the sight of the finish line . . . with all of the excitement, preparation and anxiety, don't forget to enjoy it.

And with any luck, if I see you at the finish line, it will be to say, "Congratulations," not "Where does it hurt most?"