A DEFINATE MUST IN MARATHON TRAINING

Whether you call it "overdistance", your "distance day", or "LSD" (Long Slow Distance), the long run is the essential building block of any marathon training program.

Coaches often say that it's OK to miss an occasional workout... as long as its not your long run! For the elite runner, as well as the beginner, there is no substitute for activity-specific training, and in marathon running there's clearly only one activity you should focus on.

Regular long, slower training runs - from 14 miles (25km) up to the full marathon distance or more - benefit the marathoner physiologically, psychologically, and in practical preparation for race day.

The physiological benefits are the most apparent and the most vital. During shorter aerobic exercise your body relies on glycogen, or "quick fuel" for the muscles to burn. Only after approximately 45 minutes of aerobic exercise do you efficiently start to burn stored fat cells, or "slow fuel".

After approximately two hours, the body becomes nearly glycogen depleted and relies extensively on the less efficient process of using this slow fuel for energy. Only through actually experiencing the transition to slow fuel during a long run can the runner's body become more efficient at supplying this energy to the muscles.

At the same time, the cardiovascular system must become efficient at supplying the muscles with oxygen-rich blood. Again, only prolonged exertion of the heart and lungs can increase their efficiency in delivering and utilizing oxygen.

A regular long run in your training regimen isn't only critical for race day itself. Added endurance helps you to decrease your recovery time from your speedword, hills, and cross-training workouts in the months leading up to your race so you can maximuze each of those training sessions. Being mentally strong as you approach the starting line is just as important as being physically strong. Knowing you've done training runs nearly as long as the race distance, without the benefit of decreasing your mileage before them, will leave you feeling eager to see how well you can perform after having tapered off and rested before the marathon. That's the perfect mindset for race day.

The race does not always go to the swift, however. In a race lasting hours, something as seemingly trivial as the wrong choice of socks and undo months of careful preparation. The only way to fully test your race day apparel and experience is through long training runs.

Only a long run will really let you know where you're likely to develop blisters, if a shirt creates abrasion points on your skin, if your new sunglasses will slide down your nose when you sweat, or how well you'll still like your favourite flavour of energy bar after you've eaten four in a row.

No matter where your next race is, go into it with the strength and confidence you can only get from long training runs. Because even if it's your first marathon, they'll help you feel like you've done one before.