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Mastering the Long Run

The long run is the status symbol of marathon training, but much of the existing advice on running long is misguided. Luke Humphrey breaks down just how far you should go.

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The long run garners more attention than any other component of marathon training. It has become a status symbol among runners in training, a measure by which one compares oneself against one’s running counterparts. It is surprising, then, to discover that much of the existing advice on running long is misguided. After relatively low-mileage weeks, some training plans suggest backbreaking long runs that are more akin to running misadventures than productive training. A 20-mile long run at the end of a three-day-a-week running program can be both demoralizing and physically injurious. The long run has become a big question mark, something you aren’t sure you’ll survive, but you subject yourself to the suffering nonetheless. Despite plenty of anecdotal and academic evidence against such training tactics, advice to reach (or go beyond) the 20-mile long run has persisted. It has become the magic number for marathoners, without consideration for individual differences in abilities and goals.

While countless marathoners have made it to the finish line using these programs, I believe in a different approach. Not only will it make training more enjoyable, it will also help you cover 26.2 more efficiently. While my long-run approach may sound radical, it is deeply rooted in results from inside the lab and outside on the roads. As I read through the exercise science literature, coached the elite squad with Kevin and Keith Hanson, and tested theories in my own training, I realized that revisions to long-held beliefs about marathon training, and in particular long runs, were necessary. As a result, a 16-mile long run is the longest training day for my standard program. But there’s a hitch: One of Kevin and Keith’s favorite sayings about the long run is, “It’s not like running the first 16 miles of the marathon, but the last 16 miles!”

Graphic outlining the benefits of long running

What they mean is that a training plan should simulate the cumulative fatigue that is experienced during a marathon, without completely zapping your legs. Rather than spending the entire week recovering from the previous long run, you should be building a base for the forthcoming long effort. For example, if you have a 16-mile Sunday long run on your schedule, leading up to it, you should do a tempo run on Thursday and easier short runs on Friday and Saturday. Don’t take a day completely off before a long run because recovery occurs on the easy running days. Since no single workout has totally diminished your energy stores and left your legs feeling wrecked, you’ll feel the effects of fatigue accumulating over time. This allows for partial recovery, but it is designed to keep you from feeling completely fresh going into a long run. Following the Sunday long run, try an easy day of running on Monday and a strength workout Tuesday. This may initially appear to be too much, but if your long run’s pace and mileage are tailored to your ability and experience, less recovery is necessary.

The Physiology of Long Runs

Long runs bring with them a laundry list of psychological and physiological benefits, many of which correlate with the profits of easy running. Mentally, long runs during marathon training help you gradually build confidence as you increase your mileage from one week to the next. They help you develop the coping skills necessary to complete any endurance event. They also teach you how to persist even when you are not feeling 100 percent. Since you never know what is going to happen on marathon day, this can be a real asset. Most notable, however, are the physiological adaptations that occur as a result of long runs. Improved VO2max, increased capillary growth, and a stronger heart are among the benefits. Long runs also help to train your body to utilize fat as fuel on a cellular level. By training your body to run long, you let it adapt and learn to store more glycogen, thereby allowing it to go farther before becoming exhausted.

In addition to improving the energy stores in your muscles, long runs also increase muscle strength. Although your body first exploits the slow-twitch muscle fibers during a long run, it eventually begins to recruit the fast-twitch fibers as the slow-twitch fibers fatigue. The only way to train those fast-twitch fibers is to run long enough to tire the slow-twitch fibers first. By strengthening all of the fibers, you’ll avoid bonking on race day. By now the majority of these adaptations are probably starting to sound familiar. You can expect many of the same benefits reaped from easier work from long runs too.

Long-Run Guidelines

Advice from renowned running researcher and coach Dr. Jack Daniels provides a basis for our long-run marathon training philosophy. He instructs runners never to exceed 25–30 percent of their weekly mileage in a long run, whether they are training for a 5K or a marathon. He adds that a 2:30–3:00-hour time limit should be enforced, suggesting that exceeding those guidelines offers no physiological benefit and may lead to overtraining, injuries, and burnout.

Dr. Dave Martin, running researcher at Georgia State University and a consultant to Team USA, goes one step further, recommending that long runs be between 90 minutes and 2 hours long. While he proposes 18–25-mile long runs for high-level marathoners, one must take into consideration that a runner of this caliber can finish a 25-mile run in under 3 hours. This highlights the importance of accounting for a runner’s long-run pace. Dr. Joe Vigil, a Team USA coach and scientist, further supports this notion, advising that long runs be increased gradually until the athlete hits 2:00–3:00 hours. Certainly a 25-mile run completed in less than 3 hours by an elite runner will provide different physiological adaptations than a 25-mile run that takes a less experienced runner 3:30 hours or more.

According to legendary South African researcher and author Dr. Tim Noakes, a continual, easy-to-moderate run at 70–85 percent VO2max that is sustained for 2 hours or more will lead to the greatest glycogen depletion. Exercise physiologist Dr. David Costill has also noted that a 2-hour bout of running reduces muscle glycogen by as much as 50 percent. While this rate of glycogen depletion is acceptable on race day, it is counterproductive in the middle of a training cycle, as it takes as many as 72 hours to bounce back. When you diminish those energy stores, you can end up benched by fatigue, missing out on important training, or training on tired legs and potentially hurting yourself. Instead of risking diminishing returns and doing an arbitrary 20-mile run, look at your percentage of mileage and total time spent running. (I often suggest a maximum of 16 miles, but we are more concerned with determining your long run based on your weekly total mileage and your pace for that long run.)

It may sound unconventional, but you’ll find that it isn’t random; these suggestions are all firmly based in science with proven results. As stipulated by Dr. Noakes, it is widely accepted among coaches that long runs shouldn’t exceed 25–30 percent of weekly mileage. Even so, that guideline manages to get lost in many marathon-training programs in the effort to cram in mileage. For instance, a beginning program that peaks at 40–50 miles per week and recommends a 20-mile long run is violating the cardinal rule. Although the epic journey is usually sandwiched between an easy day and a rest day, there is no getting around the fact that it accounts for around 50 percent of the runner’s weekly mileage. Looking at the table below, you can see how far your long run should be based on your total mileage for the week.

Table detailing ideal long run distance based on training volume

The numbers illustrate that marathon training is a significant undertaking and should not be approached with randomness or bravado. They also make apparent the fact that many training programs miss the mark on the long run. If you are a beginning or low-mileage runner, your long runs must be adjusted accordingly. What is right for an 80-mile-a-week runner is not right for one who puts in 40 miles a week.

In addition to running the optimal number of miles on each long run, you must also adhere to a certain pace to get the most benefit. Since we don’t all cover the same distance in the same amount of time, it makes sense to adjust a long run depending on how fast you’ll be traveling. The research tells us that 2:00–3:00 hours is the optimal window for development in terms of long runs. Beyond that, muscle breakdown begins to occur. Look at the table below to see how long it takes to complete the 16- and 20-mile distances based on pace. The table demonstrates that a runner covering 16 miles at a 7-minute pace will finish in just under 2 hours, while a runner traveling at an 11-minute pace will take nearly 3 hours to finish that same distance. It then becomes clear that anyone planning on running slower than a 9-minute pace should avoid the 20-mile trek.

 

Table showing duration of 16- or 20-mile long runs based on pace

Ask the Coach

At what pace should I do my long run?

We generally coach runners to hold an easy-to-moderate pace throughout a long run. Instead of viewing your long run as a high volume easy day, think of it as a long workout. If you are new to marathoning, err on the easy side of pacing as you become accustomed to the longer distances. More advanced runners should maintain a moderate pace as their muscles have adapted to the stress of such feats of endurance. In the long run (literally and figuratively), when you avoid overdoing these lengthy workouts, you reap more benefits and avoid the potential downfalls of overtraining.


Adapted from Hansons Marathon Method, 2nd edition, by Luke Humphrey with Keith & Kevin Hanson with permission of VeloPress.