Running Long to Run Fast?

A group of people running in a line

​How marathon training can help improve your short race speed

The Boston Marathon has always carried a certain gravitas among runners for its prestige, history and quality of competition. This year’s edition took that to a new level, with Nor’Easter-like conditions adding a brutal headwind and sideways rain into the equation. In these conditions, a staggering sixty percent of the elite field dropped out.

Far behind the leaders in corral 2, Erin Clark pushed her way through the crowds. The third-year medical student had spent the last year becoming a full-time runner, and her ambition wasn’t about to be deterred by hurricane-force winds. Running at a steady effort, Clark finished in the top 100 overall, her time of 3:01:29, a 20-minute personal best.

If that were it, Clark’s story would still have plenty of inspiration and merit, as the 24-year-old often woke at 4:30 a.m. to get in her training miles and managed to balance her medical studies and her role in the newly formed Raleigh Distance Project. Instead, Clark kept running. Three weeks after her Boston PR, Clark lined up and ran a PR of 5:20 at the Rocket City Mile in North Carolina.

“I wish I’d run one second faster,” Clark says with a laugh. “I’m still disappointed with that.”

Clark’s story isn’t unique. The notion that marathon training “saps the body of speed”– a platitude that was tossed around with near certainty for most of the 20th century – has gradually lost favor as elite athletes like Shalane Flanagan, Molly Huddle, Mo Farah, Magdalena Boulet and Amy Cragg set PRs in shorter distances after turning their attention towards the marathon. It does beg the question, though: how can you make marathon fitness work for you at the shorter distances?

What Marathon Training Does Well

Aerobic Capacity

Ever since coaching legend Arthur Lydiard identified the importance of building an aerobic base in the 1960s, accumulating mileage has been considered sacrosanct in the distance running community. All races longer than 400 meters require predominantly aerobic energy, with races such as the 5K, 10K, half marathon and marathon relying on this energy system for 90 percent or more of all expended energy.

Nothing develops the aerobic system quite like marathon training. The high volume of miles, many of them at an easy to medium intensity, are ideally suited for developing a distance runner’s aerobic capacity. This shows up in the form of a large, efficient heart that pumps more blood with each beat (stroke volume), a lower resting heart rate and an increased VO2max (maximal oxygen uptake).

Long runs maximize these adaptations, and good marathon training is loaded with them. Getting out and running for two to four hours at a time causes a number of intracellular adaptations, like increased capillary density, increased number and size of mitochondria, better glycogen storage and muscle fiber changes. All of these adaptations benefit someone competing in a 5K just as much as a marathon. It’s one reason that world-class 5K runners, despite never racing more than 3.1 miles at a time, often train upwards of 120 miles per week.

Higher Lactate Threshold

Most marathon build-ups also include a heavy dose of lactate threshold work. Also known as tempo runs, these workouts – usually performed between your 10-mile and half-marathon race paces – seek to increase the pace at which your body produces lactate, an energy source that serves as a marker that you’re using anaerobic (read: less sustainable) energy.

Marathoners encounter threshold work in various forms. Traditional tempo runs, long marathon pace efforts, alternating pace workouts, cruise intervals, fartleks and hilly runs (to name a few) all increase your lactate threshold pace. The faster you can go without high levels of lactate flooding your body, the faster you can race. That’s especially true in races between 5K and the half marathon, where the increased pace results in more lactate production. Marathon training essentially buffers against this onslaught, resulting in better performance.

Musculoskeletal Adaptations

The higher mileage of marathon running doesn’t just increase your cardiovascular fitness levels. It also develops muscles, ligaments, and tendons that are more resistant to the pounding those miles produce. When the body breaks down under stress and then rebuilds stronger than before, a process known as supercompensation is occurring. This is the bedrock of all fitness gains.

Converting Marathon Fitness to Speed

All good training plans are built on the idea of specificity. Think of it like a tiered cake. The bottom layer is your aerobic capacity. This work can pay dividends over the long course (as aerobic fitness is paramount in almost all distance races), but to stand the most benefit you need to add some smaller, more specific (and delicious!) layers to the top of the cake. These include learning how to run faster and incorporating race-pace intervals. All the aerobic fitness in the world can’t be put to good use unless you have the leg speed to apply it in the first place.

That’s one reason that many coaches now recommend marathoners bounce back from a goal race with a season of shorter, faster races. Redoing the base period all over again would essentially be redundant. Better to take the offseason and work on training elements that can be fixed and enhanced to make you a better racer.

That was certainly the case with Clark after Boston. Two weeks of speed workouts, easy runs and little else followed a week of short recovery runs. With plenty of residual aerobic fitness, the speed work bridged the gap between the endurance of the marathon and the quickness of the road mile. When race day arrived, Clark had more than enough spring in her step. She also had a mental bonus.

“The mile felt so short compared to Boston,” Clark says. “Pacing was hard because I was accustomed to leaving some gas in the tank for the last 10K [of a marathon], which is obviously unnecessary in a mile race.”

Making Your Own Plan

Whether you want to take your marathon fitness and convert it into a mile or a half marathon, the principles are the same.

  • Recover first. All the fitness in the world can’t be put to good use unless your body has fully healed. Marathons are taxing races both physically and mentally; rush back too soon and you risk injury, illness or stalled-out training.
  • Trust your gains. After a good marathon, it can be easy to fall into the trap of believing only high mileage and long workouts can maintain or increase your fitness. Those training periods have their place, but while you play at the shorter distances it’s actually beneficial to drop your total volume and run shorter workouts.
  • Identify the specific needs of the race. Specific race fitness is boosted most by training within a few seconds per mile of your goal pace. That means milers should be doing short intervals close to mile pace and 10K runners should be doing longer intervals closer to 10K pace. A good rule of thumb is that race-pace intervals should be 20-33% of the race distance length (i.e. 5K runners should run intervals of 1000m to 1600m intervals at 5K pace).
  • Don’t forget the speed. It’s all relative, but running fast offers a wealth of benefits to all. Short intervals lasting 40 seconds or less at near maximal speed offer the biggest bang for the buck, as the body becomes faster, more flexible and more efficient from these sessions.

Enjoy the brevity. After racing 26 miles, racing three sounds like a lark. Use that shorter duration to your benefit. If you could push through several hours for a well-earned result, just think how “easy” pushing for 30 minutes or less will be.

By Philip Latter. Latter is a former senior writer at Running Times and co-author of Running Flow and Faster Road Racing. His work has also appeared in Runner's World,, and He currently coaches athletes at The Running Syndicate, in addition to his day job coaching high school runners at Brevard High School (NC).