By increasing the length of your long run during training, you can extend your endurance for any race distance. If you run slowly enough, taking liberal walk breaks, you can continue to push back your “wall” almost indefinitely with virtually no risk of injury or excess fatigue. The most exciting part of this, for most runners, is that longer runs tend to translate into faster times.

In numerous surveys, I've found that those runners whose longest run is 20 miles tend to improve by an average of 15 minutes when they build up to a 26-mile training run in the month before a marathon race. As noted in my books Galloway Training Programs and A Year Round Plan, an additional average improvement of 11 minutes is available when increasing 26 miles to 29 miles, four weeks before the marathon.

Better endurance can also help you improve times in shorter events. Five-kilometer times tend to continue to improve as the long-run training increases, up to 12 miles. 10K times improve when long runs increase up to 17 miles, and half-marathon times improve when the longest run reaches up to 19 miles.

Long runs must be run very slowly, and increased gradually. I recommend that your long-run pace be at least two minutes per mile slower than your current race pace in any given event – but it's even better to run three minutes per mile slower. The slower you go, the faster you recover. I've not found a long-run training pace yet that is too slow – you get the same endurance benefits whether you're going super slow or fast. By running slowly and walking often, you can carry on your life activities, even after a 26-mile run.

To maintain your current long-run endurance, you need to run it every other week (distances fewer than 17 miles), or every third week (distances 17 miles or longer). On the non-long-run weekends, you can run a distance that is between one third and half of your current long run. Two other runs are needed during the week, for a minimum of 30 minutes each. By gradually increasing the distance of longer sessions, with liberal rest breaks (see sections below), your muscles, feet, bones and energy systems will adapt – giving you more stamina for everything you want to do in life.

• Increase your long one every other week by one to two miles.

• Have two 30-minute maintenance sessions during the week. These can be done at any pace you wish, provided that you are recovering quickly. Veterans can run significantly longer than this if they don't experience problems by doing so. Going farther on the short days will not improve your endurance, according to my experience.

• Go very slowly for the entire distance. Speed does not help your endurance. Only by increasing the distance of the long one do you improve stamina. Runners should be running at least two minutes slower than their current race pace, but three minutes/mile slower is even better.

• Runners should take walk breaks from the beginning of all long runs. When you're increasing the distance of a long workout, insert a one-minute gentle walk, according to the pace chart below. For more information, visit www.RunInjuryFree.com.

Be regular! If you don't have time for a workout, just walk slowly for five minutes. This minimal amount will help to maintain most of the adaptations. Besides, if you get out there for five minutes, you'll often end up doing 10 or 20 minutes.

Walk break frequency for runners

9 min/mi: run four minutes, walk one minute
10 min/mi: run three, walk one
11 min/mi: run two and a half, walk one
12 min/mi: run two, walk one
13 min/mi: run one, walk one
14 min/mi: run 30 seconds, walk 30 seconds
15 min/mi: run 30 seconds, walk 45 seconds

Runners tend to improve more quickly if they are consistent with their long runs and their maintenance runs. Try to run about every other day.

Olympian Jeff Galloway has helped over a million runners and walkers improve their lives thorough his books, beach retreats, running schools and individual consultations. For more information, see his book Running Until You're 100 or visit www.RunInjuryFree.com.