By Mackenzie Lobby • Active.com

Touted as one of the most important aspects of endurance training programs, the long run is non-negotiable when it comes to preparing for a marathon. Oftentimes it is the main element that sets you apart from someone training for a 10K. What’s more, it is the long run that can convince even a novice that a marathon is within reach.

Therein lies one of the long run’s greatest benefits. It teaches a runner that the marathon distance is possible.

While six miles may be your longest run today, gradual increases will help you build up to run 20 miles in a short few months. In addition to the mental benefits, the long run also offers a host of physiological advantages that help you get to the finish line on the big day.

Mental Benefits

The marathon distance is not for the faint of heart. There’s a reason it is on many people’s bucket lists; it’s a monumental accomplishment. In addition to the physical difficulty involved in running 26.2 consecutive miles, many soon-to-be marathoners are most intimidated by the mental aspect. They find themselves asking: Am I really capable of running that far?

The slow build-up of your long run every week allows you to slowly build your confidence in the same way you build muscle strength. While one mile may be a struggle six months from race day, steady increases from one week to the next will help make that final goal seem more realistic.

The long run also plays a major role in helping you increase your coping skills and mental toughness. You never know what’s going to occur on race day: blisters, stomach aches, leg cramps, rain and wardrobe malfunctions happen. It’s better to learn to deal with them in training, willing yourself to finish a long run even when the circumstances aren’t ideal. You’ll soon feel confident that you can handle just about anything when you toe the line on race morning.

Physical Benefits

In addition to the psychological benefits of the long run, it also helps to train your body for the marathon distance. From increased VO2 max (or aerobic capacity) to a stronger heart and increased capillary growth in the muscle fibers, the payoffs are many.

One of the biggest physiological benefits is increased muscle strength. As you run longer, your body will first rely on slow-twitch muscles. As those fatigue, you become dependent on the fast-twitch muscles. If you haven’t run long enough in training to strengthen those fast-twitch fibers, you’re likely to be hurting on race day. The only way to build those muscles is to go long.

Long runs also assist the body in storing a greater amount of glycogen, which is where your body gets energy during a long, hard effort. As the body depletes its glycogen stores, it then goes to the fat stores for energy. Once this transition occurs, many marathoners feel as if they have “hit the wall.” The long runs train your body to store more of that glycogen, thus increasing your ability to run longer without getting fatigued.

How to Run Long

Once you find a marathon training plan that is right for you, you can begin mapping out your long runs. While some do a long run once a week, others like to operate on a 10-day cycle. Novices and more injury-prone runners can even get away with doing a long run every two weeks.

During an 18-week training program, a newbie will likely get in around eight to 10 long runs that are 12 miles or more, peaking at 20 miles. A more advanced runner will do at least 10 to 12 long runs that are 12 miles or more, peaking at 22 to 24 miles. Avoid going more than 10 to 15 percent farther than your last long run. This way you allow your body to adapt to each long effort by slowly increasing the mileage. Be sure to take two to three full weeks away from long runs before your big race.

Remember that the focus of the long run is distance, not speed. You should be running these runs 45 seconds to a minute slower than your goal marathon pace. If you are looking for a challenge, pick up the pace the last 3 to 4 miles to teach your body to finish strong. Most importantly, settle in and learn to love the long runs. Your body and mind will thank you on marathon day.