There’s been recent discussion (Fitness and Nutrition, June 20, 2011) on the “10% rule” – the widely held belief that to avoid injury you should increase your mileage by no more than 10% from week to week. The fact is, the article states, that the origin of the rule is not documented and recent studies comparing those who followed the rule with those who didn’t do not support it.

What, then, can be said about mileage?

- Know that “more is better” is not a solution. For many, the goal of training is to run faster, not longer.

- The 10% rule is a useful guideline that’s worked for many – it’s a pretty good rule of thumb if you’re wondering about increasing mileage.

- Depending on your age, sex, fitness and weight, everyone has a different mileage limit which leads to injury. For some, mileage of 20 miles may be maximum while it may be 60 or more for others.

- If you do want to increase mileage, once you get up to your maximum number of training days per week, stay at that level for a few weeks. Increase the distance first of your long run, then your medium run.

Avoid sudden changes – in mileage, shoes, surface on which you run (packed, even dirt is more forgiving than asphalt which is more forgiving than concrete). Also, if you increase mileage from week 1 to 2 to 3, cut back by 10% to 25% on week 4 depending on where you are in your training cycle. On week 5 you can resume training at the mileage held during weeks 2 or 3 to keep progression gradual.

- Lower mileage if

o you increase your pace significantly for training runs
o if you add more speed work as you sharpen for a race
o you are tapering for a race, you race often
o you’re recovering from injury
o you’ve completed your racing season or
o you sense signs of an illness or injury.

If you’re just looking for fitness, remember Dr. Ken Cooper’s advice: 15 miles a week is all you need.