Why 20 is enough for 26.2

You don’t need to train the full distance to reach the finish line.

For marathoners, one of the most psychologically daunting aspects of endurance training is the gap between their last long run (usually between 20 and 22 miles) and race distance, the full 26.2. If you’ve trained for a marathon before, there may have been times when you doubted your ability to cover those final miles. Yet, come race day, you probably did.

“Just because you haven’t done something doesn’t mean you can’t,” says David Siik, Los Angeles-based creator of Equinox’s Precision Run program. “Humans come from a heritage of having to cover great distances just to survive and live day to day. Deep within us all is the gift of enduring.”

Joe Layden, Ph.D., a professor of health and exercise physiology at Plymouth Marjon University in England, puts it bluntly: “The reason we don’t run the full marathon distance in training is that we do not need to.”

The fitness to accomplish 26.2 is achieved in two ways: First, logging frequent runs (lasting 20 to 40 minutes) increases your oxygen uptake and your body’s production of hemoglobin, a protein in red blood cells that carries oxygen from the lungs to the tissues. Together, those changes improve your body’s aerobic capacity.

Second, longer runs train your body’s fat-burning abilities so you don’t crash when carb stores run out, Layden says. Running 20 miles is more than enough to teach your body to tap into this extra energy source. The net effect of taking this approach to training is that you have the physiological system in place to run a full marathon, as long as you fuel and hydrate throughout.

Completing the distance is also largely mental, explains Layden’s colleague Alister McCormick, Ph.D., a professor of sport and exercise psychology who studies the psychological demands of endurance events. The biggest race-day hurdles have nothing to do with fitness: staying motivated, pushing past low moments, and coping with discomfort, to name a few.

That’s all much harder to accomplish on a solo long run than it is on the big day. The atmosphere, competition, and camaraderie that come with race day can breed perseverance. “The sheer excitement and inspiration absorbed at the starting line and from the roar of a crowd can fuel you far beyond what you ever thought you could do,” Siik says.

Rethinking the finish line is another way to make it there. Race distances simply describe how far you’re tasked with going, not how far you can go. “People often have that backwards,” Siik says. “Distance boundaries are just lines drawn in the sand by our minds. Our bodies are almost always capable of erasing them.”Photo: Erik Umphery/The LicensingProject.com