The legendary marathon runner Bill Rodgers (four-time New York, four-time Boston Marathon champ) once remarked that in order to be a successful distance runner, you need to be part athlete, part scientist. What Rodgers meant was that performing well in endurance sports often leads to a deeper understanding of exercise physiology.

Let’s take the half-marathon distance for example—an event we’ve talked a lot about lately, especially, with the Hill Country Halloween Half Marathon in Cedar Park coming up on Saturday, October 28 at 7:30 a.m.

One of the promos for the race suggests that you could use it as part of a training build up for the Houston Marathon in January. Here’s where the physiology comes in. While it’s true that runners can learn a great deal from running a half, comparisons of the 13.-mile half-marathon to the full 26.2-mile marathon are often misunderstood.

Researchers have learned that higher mileage alone does not prevent marathoners from suffering fatigue and leg soreness.

It would be easy to think that it’s simply that the marathon is twice as far, so it’s going to be twice as hard. It’s actually a lot more complicated than that. And anyone who has ever run a marathon, knows that it’s a lot more than twice as challenging than a half. But why is that?

A recent study in the Journal of Sports Medicine and Physical Fitness took a closer look at comparing the two distances, and the results yielded some interesting facts. The Spain-based researchers used the annual Madrid marathon and half-marathon to track runners as both races take place at the same time and on the same course (for the first 13.1 miles).

Pre-race, a small group of runners (both half and full marathon) had blood drawn to check baseline indications of dehydration and biochemical markers of muscle damage. Additionally, the scientists looked at things like standing vertical leaps and weight.

Upon completion of the race, they conducted similar tests, and then set about comparing the data. Much of the findings were predictable—the half marathoners showed much lower levels of blood markers related to muscle damage than the full marathoners, and their vertical leaps showed that their legs were still pretty fresh.

Again, as expected, the way the races played out was quite different: the half-marathon runners were able to maintain a steady pace throughout, and even speed up for the last 5K, while the 26.2-mile runners slowed down progressively after the first half. Neither group showed signs of dehydration, so that was not the culprit—the big “why” in what made the marathoners slow so much.

What the researchers did learn, was that despite training higher mileage than their half-marathon runner counterparts, the marathoners still suffered fatigue and leg soreness as the race wore on.

The researchers concluded that running long distances alone may not be enough to prepare for the damage incurred to leg muscles by running a marathon. They suggest using gym training with exercise machines and free weights to target specific leg muscles to develop the strength and power to handle “over-the-top” distances like the marathon.

While most runners don’t think much about the gym as a way to help their speed, when it comes to the marathon, maybe we should listen to the scientists. Bill Rodgers would be proud.

Upcoming races: Hill Country Halloween Half Marathon in Cedar Park coming up on Saturday, October 28 at 7:30 a.m. Also Saturday, October 28 at 800 a.m., the Run for the Hills 5K/10K at the Hays Hills Baptist Church (1401 N FM 1626 in Buda.