Building Your Mileage Base

Without question, one of the most important things to focus on during marathon and half marathon training is to safely build a mileage base. This is why you training plans gradually increase the weekly and long distances over the duration of the plan. The basic training for all distance running and racing is endurance training. This is because, as a runner, you must acquire the stamina to run for long periods of times or for long distances. Long runs, which most people run on a Saturday or Sunday, are therefore known as your Long Slow Distance (LSD)run.

Follow Me on PinterestBase building means starting from a lower base of infrequent mileage and progressing to more frequent runs including two, three or four shorter runs and one long run per week. For the beginning runner, base building is most commonly defined by building regularity in training at consistent, easy-to-moderate effort levels while high-intensity training and speed work is left to more experienced runners who have already established a base. While base building, mileage should increase by no more than 10 percent each week (for your total weekly mileage, including your LSD) and intensity should be kept at an easy to moderate level. By following the increases in the training plan, you are steadily building a base to help you to run strong and hopefully injury free. As you progress in your running career, the base building phase diversifies to include short and long easy runs, hills runs and interval speed workouts.

This is called the 10 Percent Rule.  For example, If you’re running 10 miles a week now, and you want to increase your training, run 11 miles next week. And 12 the week after that. And 13 the week after that. This may look like agonizingly slow progress, but in just 8 to 10 weeks, you could be running 20 miles a week. Your mileage will only increase from there. For many runners, this is seemingly slow progress and the biggest challenge is often their own enthusiasm – you feel great, you want to run more and more! And at first, while sticking to the 10 percent rule may seem painstakingly slow, it will lead to astronomical amounts of running compared to where you started.

Another important factor of base building for the beginning runner is cross-training because it serves as active rest for the running muscles. By alternating running days with cross-training days, your body can train at a higher frequency without the risk of injury from running back-to-back days. Cycling, swimming or any other types of aerobic activity are good cross-training activities for runners. Total body strength training one or two days a week to begin with can also contribute to your running success by building strong muscles, tendons and joints to withstand the impact of running. Complete rest days – with no strenuous activity at all – are also important in allowing your body time to recover from your workout and be ready for the next one.

The base building progression is different for everyone depending on your fitness level, exercise, sleep and eating habits. The important part is that you are increasing your mileage gradually and conditioning your body to run for longer distances and longer amounts of time. Following an easy progression of miles builds not only your cardiovascular endurance, but helps strengthen the muscular and connective tissues that enable your body to tolerate long training runs. As a beginning runner, building a sound mileage base is more important than getting faster. Take it from me as a 13 minute mile Coach, slow is perfectly fine! There will be plenty of time to develop speed and agility as you progress through your running career. For starters, you must create the building blocks to keep you running healthy, fit and strong so you can get to the starting line of your first distance race.

Until the next mile marker,


  1. RunningMandy says

    I think I’m reading this wrong – did you mean to suggest that the 10% rule applies to LSD runs? I know the rule applies to mileage total, but the LSD? (For a 5 mile run, that would only be an increase of 0.5 miles!)

    Safely building a mileage base is definitely huge! And way more important than speed! 😀

  2. Hi Mandy. The 10PR applies to your total weekly mileage, including your LSD. I reworded it to be clearer – thanks for the heads up!

  3. RunningMandy says

    I knew I was reading it wrong! Nice re-phrasing!

  4. I am a big believer in the conservative approach to distance and speed. Any time I deviate, well, not good results! You spelled it all out very well.

Speak Your Mind


This site uses Akismet to reduce spam. Learn how your comment data is processed.