Marathoners often fear that by running shorter distances after a marathon they will lose their endurance through less mileage. This is not necessarily the case, provided that the reduction in running volume is met with an increase in running pace.

A sound method of estimating the speed that you should be running at when running shorter distances is by using the ten second rule working down from your own marathon finishing time time. The formula requires that  you increase the speed of running by ten seconds a mile as the race distance declines.

Consider the following example based on a seven minutes/mile marathoner who finished in 3:03:24. If they were to run the events below, their pace would need to be as follows:

Remember, these are just a guide. These estimations can be toughened up or extended to suit personal needs. The next stop is to work out the approximate 400 metre times for track work.

The above example will be:

Again, using the table above, we can estimate our target times for the lesser distances:

If you’re not too keen on track running, you can use a heart rate monitor with just as good effect.

• Half marathon pace will be 75% of maximum heart rate (MHR)
• 10k pace at 90% MHR
• 5k pace at 95% MHR
• 3k pace at 100% MHR

For the half marathon pace, the duration of effort will be for 10 minutes; for the 10k pace it will be for eight minutes; 5k will be six minutes, and 3k will be four minutes.

After each effort, jog until the heart beat rate returns to 120 beats a minute. Build up from two efforts to at least four.

If you have never run a ten mile race you can estimate your potential at the distance with the following formula:

1. Divide your marathon time by three
2. Add five minutes to the calculation in 1

For example if your best marathon time is four hours, your ten mile potential will be 85 minutes; if three hours, it will be 65 minutes, and for two and a half hours it will be 55 minutes.

Note that the fastest-ever British marathoner, Steve Jones, with a time of 2:07:13, had a best of 46:49 for ten miles. Using the formula stated, this works out at 42 minutes plus five minutes; a total of 47 minutes!

Relative speed work for the marathoner not accustomed to it should be tackled cautiously, with one session a week at the target race speed for a month; if the goal is 60 minutes for ten miles, start with either five miles in 30 minutes or six times one mile on a track or measured course with a 45 second rest, at race speed. Other sessions the same week can be 20 miles, 15 miles, and 13 miles.

In the second month, two speed sessions a week can be done, one as stated and one faster at 10k pace. The maximum number of speed sessions in a week should not exceed three.

At first, the recovery times after repetitions, where applicable, should be jogging half the distance of the repetition at the rate of 45 seconds per 100m. This should progress to jogging a quarter distance and even an eighth distance of the repetition if times are achieved. This particularly applies to 5k and 10k pace workouts where there is no opportunity for taking a breather. It’s one relentless mile after another, so you have to train for this. Good luck.