How to Build Mileage for a Marathon without Getting Hurt


Building mileage while training for a marathon is a very serious business. Building too quickly, or not quickly enough, can leave you injured and ineffective on race day. Running 26.2 miles is a sobering effort; one that requires months of training on top of base mileage. There is no shortage of training plans available to help you build mileage, and with a little experimentation you should be able to quickly choose a program that suits your needs as a marathoner in training.

Before you begin building mileage to follow Pheidippides’ footsteps, it is imperative to have a base mileage established. The rule of thumb I often use to advise newbie runners is to make sure that you can run comfortably (at any pace) for 30 minutes or 3 miles before attempting to build distance. Build your base mileage slowly, by running at a comfortable pace with periods of anaerobic threshold to push you into higher speeds and mileage before beginning your training program. Once you feel comfortable with your baseline, you can slowly begin to implement your training program.

A training program for a marathon should last between 3 – 5 months. Shorter than this might cause injury from building too quickly, while prolonged training might cause injury from over training. Personally, I have fallen into the latter category more than once. My first race cost me tibial stress fractures due to overtraining.

I got so addicted to the runner’s high, and so nervous about making mileage that I over trained. In my zeal, I pushed through my shin splints (with a ridiculous “no pain no gain” mentality) and ran until I literally could not take another step. A trip to the doctor confirmed my worst fears; tibial stress fractures. I spent the next six months in bilateral casts instead of running shoes.

Building mileage at 3 miles per week is a safely structured plan to increase distance without risking injury. This does not mean that in 12 weeks you will run 36 miles. In a marathon training program, you should only run up to 24 miles prior to race day. Some training programs will advocate running post marathon mileage; however, this should only be undertaken by advanced or even elite runners seeking to hit a personal record.

Once you have hit 12 miles, take a week to go down to 10 miles for your long run. Your training week should consist of 4 – 5 days per week running, hitting 2-5 miles two days (with speed work), 8 miles one day, and a long run which is gradually built over time. Alternate days should be reserved for cross training or strength training. You should also take one day per week off of working out altogether, to rest. This is as essential to your training regimen as your long runs.

Once you have built your mileage over the 12 mile mark, you should continue to build every 2 weeks with a taper to 3 miles under your peak in between. Once you have hit between 22 – 24 miles, you will begin to taper your long runs down between 15 – 18 miles until race day. Do not worry about not hitting the full marathon distance in training; the race energy will carry you much further than your training. Once you have hit your peak mileage, you have completed full readiness for the marathon.