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Running more miles is the key to many running goals, from losing weight to completing a marathon to improving your 5K time. Elite runners, already born gifted and fast, often put in 70 to 100 miles or more per week to be their best — even milers. Most of us will likely never approach that much — and don’t need to — but running more, however much that is, will transform your body. Miles build strength, enhance your ability to turn oxygen into energy more effectively, and make you a leaner, more efficient running machine.
Most runners know, however, that they can’t just double or triple their workload or they will get hurt. To keep from doing too much, too soon, they build their volume gradually as they work their way higher up the mileage mountain. But how should you structure that climb?
Straight Up vs. Switchbacks
Many follow the “ten-percent rule” — adding approximately 10 percent of their weekly mileage to their total volume the next week. An aggressive increase from 20 to 30 miles per week, for example, might go from 20 miles per week to 22, 25, 27, then 30. While runners may survive this schedule unhurt, this approach can promote fatigue, says Jonathan Dugas, Ph.D., a triathlete, coach and exercise physiologist, and co-founder of The Science of Sport. If you keep increasing week after week, Dugas says, “You’re just coping, coping, coping, and you’re not maximizing your adaptations.” Building fitness and strength requires hard training but also requires periods of rest or lighter work to permit the body to adapt more optimally.
As runners, we tend to tackle challenges head on. If we have to scale a mountain of more miles in our training, the most direct way to conquer it is to head straight up, right? Few mountain roads, however, follow such a straight, impossibly steep route — cars would burn out their transmissions or stall and slide back down. Instead, roads follow switchbacks, cutting more gradual gradients across the face of the mountain and doubling back, alternating short steep climbs with a level section or even a slight decrease in elevation. A smart ascent up the mileage mountain follows a similar route.
Rather than a relentless gradual climb, a safer and more effective approach is to increase miles for two to three weeks, then maintain that level for a week or two until your body has adapted to it and it feels comfortable before increasing again. Some runners drop back down slightly after each climb, or even alternate harder and easier weeks.
Building toward 140-mile weeks before her Olympic medal in Athens, for example, Deena Kastor reportedly alternated each new mileage high with a recovery week, logging totals of 80, 70, 100, 80, 120, 100, 140, 100, 140, 100… Another top runner, John Mirth, a 58-year old whose running cred’s include qualifying for the Olympic Trails three times and placing 4th as a master in the 2004 Boston Marathon, told me he adopts a similar pattern these days, alternating 80-mile weeks with 50-mile weeks. Those of us with more mortal miles can apply their percentages, taking regular “down” weeks of 20 to 30 percent fewer miles before increasing again.
Arrive at the Top Strong, Not Stressed
Incorporating switchbacks into your plan lets the training effect happen: Your body has the chance to grow stronger in response to the stress you’re putting on it. “Part of being able to make adaptations and benefit from training stimuli is giving the body time to recover and form those adaptations,” Dugas says.
Planned recovery weeks also allow you to train harder. “The whole point is to crank up that training stimulus,” Dugas says. “You want to send the strongest stimulus you can to the body to make those adaptations. It requires laying it on kind of thick.” Recognizing that everyone’s limits differ, Dugas says you want to add load until you get to the edge where it starts to feel like too much, then reduce it i order to recover. For most of us mortals that happens after 3–4 weeks of progressively higher mileage.
“You build up that training stress, then come back down,” he says. The recovery period isn’t an off week. “You still keep on training, but you’re balancing the training load so now your body can focus its energy on solidifying those adaptations instead of just coping with the stress. It’s about doing as little as possible to remind your body to maintain its gains while maximizing the ability to make new adaptations.”
One reason people resist down weeks is that they fear losing their fitness gains and having to start the progression again. Dugas assures, however, that this is not the case with the cardiovascular and metabolic changes you get from endurance training. “You don’t have to build it up again,” he says. “Those adaptations that help you run longer, they don’t go away very quickly.”
A possible pattern using switchbacks for a runner doing 20 miles per week might be increasing to 23, then 27, back down to 20, then go to 30. You get to the same place in the same amount of time as the steady climb, but you arrive there feeling rested, strong, fast, ready for the new level, and eager to start the next climb.