Take the guesswork out of determing your best target pace for races and workouts.

There’s a very simple way of telling how fast you should run on long runs, and what you are currently capable of running in races.  It’s a one-mile time trial that is inserted into one of your shorter runs, about every two weeks.   This can help you set realistic goals for races so that you won’t start too fast.  This “magic mile” will also tell you very accurately what you should be running on long runs.

For more than a decade, I’ve analyzed how much runners slow down when they go from a fast one mile to an average mile in a hard 5K, 10K, half marathon, and marathon.  After looking at thousands of computations, the numbers speak for themselves.  The full explanation is in my books Year-Round Plan, Half Marathon and Galloway Training, but here are the key points:

Galloway’s Prediction Formula:

Take your one-mile time trial time and adjust to find a potential fast pace for you, in each race:
5K—add 33 seconds
10K—multiply by 1.15
half marathon—multiply by 1.2
marathon—multiply by 1.3

Example:  You ran a fast (for you) one-mile time trial and the time was 10:00. In this case, 10:33/mile  is your current potential for a very hard pace in a 5K; 11:30/mile is your current potential for a very hard pace in a 10K;
12:00/mile is your current potential for a very hard pace in a half marathon;
13:00/mile is your current potential for a very hard pace in a marathon.

To determine your long run pace, add two minutes to the predicted marathon pace. In this case it would be 15:00/mile.

In order to run the time in the race indicated by Galloway’s Prediction Formula it is necessary that:

  • You have done the training necessary for the goal
  • You are not injured
  • You run with an even-paced effort
  • The weather on goal race day is below 60F or 14C, with no strong headwinds, no heavy rain or snow, etc.
  • There are no crowds to run through, or significant hills

Here’s how to do the the “magic mile” time trial (MM):

  1. On your MM time trial, don’t run all-out from the start—just a little faster than you have been running.
  2. Go to a track, or other accurately measured course.  One mile is 4 laps around a track.
  3. Warm up by walking for 5 minutes, then running a minute and walking a minute for 6-10 minutes, then jogging an easy 800 meters (half mile or two laps around a track).
  4. Do four acceleration-gliders.  These are listed in the “Drills” chapter of my books.  Don’t sprint.
  5. Walk for 3-4 minutes.
  6. Start the MM.  Run fast—for you—for 4 laps.
  7. Start the stopwatch at the beginning of the mile and stop it at the end of the 4th lap.
  8. Cool down by reversing the warm-up.
  9. A school track is the best venue. Don’t use a treadmill because they tend to be notoriously un-calibrated, and often tell you that you ran farther or faster than you really did.
  10. On each successive MM, try to adjust pace in order to run a faster time than you’ve run before
  11. Use the “Galloway Prediction Formula” above to see what time is predicted in the goal races

How hard should I run the test?

During the first month of the program, you could run the magic mile once a week, in the middle of a Tuesday or Thursday run.  The first one should be only slightly faster than you normally run.  With each successive MM, pick up the pace and beat your previous best time.  By the 4th one, you should be running fairly close to your current potential.

Long run Pace

It never hurts to run slower on long runs.  By adding 2 minutes to the predicted marathon pace, as noted above, you will have a pace that is unlikely to cause injuries, and very likely to allow for a fast recovery.

Adjust for heat

During long runs and long races I’ve found that most runners slow down about 30 seconds a mile for every 5 degrees of temperature increase above 60F.  On long runs, half marathons and marathons, it is best to make this adjustment from the beginning of the run.  On 5K and 10K races the slowdown is more like 10-20 seconds/mile slowdown for every 5 degrees above 60F.

How to get faster on each “Magic Mile”

  • Try to run every one of the MMs on the schedule.
  • Adjust your pace on each lap so that you run a little faster during the last 2 laps.
  • Hint: hold yourself back on the first lap!
  • Most runners will improve the MM on most attempts if training is done properly, and rest days are taken.
  • If you are not making progress then look for reasons and take action.
  • The fastest time run during the last few MMs will predict a very hard race pace.
  • You can then adjust your pace due to temperature and effort level desired.