How do you go about pacing a marathon? There are lots of possible answers to that question. You could approximate it based on perceived exertion and what feels sustainable for a marathon. You could use past marathons as a guideline. You could light candles and conduct a Ouija board seance, asking the spirits for their guidance. The dark arts would definitely need to get involved for me to run a negative split.
Many coaches add some earthly objectivity to marathon pacing by using pace calculators. There are lots of great ones, including the Jack Daniels VDOT Calculator and the Hansons Running Race Equivalency Calculator. The general principle is that by knowing how fast an athlete can race a shorter distance, you can determine approximately how fast they are capable of running the marathon.
After all, in a 50 miler, you can run a fast 5K and still have 47 miles to go, so shouldn’t you just focus on training to support long runs? The pace calculators tell a different story.
Usually, the calculators are pretty darn accurate. For example, many of the athletes I coach will do one final, hard workout 10 to 12 days before a marathon, often involving a hard tempo effort. Vitor Rodrigues had a hard 10K just 12 days before the New York City Marathon, crushing his PR to run a 34:44. Plugging that time into the calculators gave him the confidence to pace NYC aggressively, leading him to a PR of 2:38 (less than one percent different than predicted).
In my experience, barring injury or going out too fast, athletes are within 1 to 3 percent of the time predicted by a hard effort leading up to the marathon, even if that hard effort is as short as 5K.
What does running a 5K hard have to do with running a marathon? Everything, it turns out.
Short-distance speed and long-distance speed are correlated
Running events over middle distance are kind of like chain Tex Mex food. They all involve similar ingredients, just in different proportions and configurations:
A 5K is a well-developed velocity at VO2 max, a solid lactate threshold and enough aerobic development to handle the harder workouts.
A marathon is heavy on the aerobic development to limit glycogen consumption at faster paces, solid lactate threshold and a base of velocity at VO2 max so that running economy is optimized.
One is a burrito, one is an enchilada, but both have beans, rice and delicious, delicious hot sauce.
Leading up to a 50 miler, you probably don’t want to be in 5K PR shape since that will mean your training has been too skewed to fast running at the expense of slower, more specific trail training. However, your trail ability will likely be way more efficient if you actually get fast at some point.
In trail-running training, though, it’s tempting to focus on just one ingredient. After all, in a 50 miler, you can run a fast 5K and still have 47 miles to go, so shouldn’t you just focus on training to support long runs?
The pace calculators tell a different story. Short-distance speed and long-distance speed are correlated, dependent variables. Focus on one without the other for too long, and eventually both can get capped out.
Things are more complicated on trails, where there is often more elevation change (requiring resilience and stressing economy over variable terrain) and sometimes longer distances (requiring a heavier emphasis on specific endurance training). Leading up to a 50 miler, you probably don’t want to be in 5K PR shape since that will mean your training has been too skewed to fast running at the expense of slower, more specific trail training. However, your trail ability will likely be way more efficient if you actually get fast at some point.
To put it another way, imagine two athletes competing in a 50 miler on trails. In the last year, one ran a 5K in 19 minutes, the other in 20 minutes. Otherwise, they have similar training. Now let’s add some spice to this enchilada. You owe a bookie $50,000, so you’ve maxed out your credit cards to make one last attempt at getting the money before you sleep with the fishes. Which athlete do you bet on?
If you bet on the 19 minute 5K runner like I did, you intuitively assume that the pace calculator logic also applies to longer trail events. I’m guessing you’d be even quicker to take the bet if it was a trail half marathon.
Winter is a great time to get fast
The problem is having the time and energy to optimize speed when you don’t want to focus on it too close to big races or when the beautiful mountain trails are calling each weekend. If only there were a time of year when there were few trail races to specifically train for . . . and it was cold . . . and there was less time due to holidays and limited sunlight. Oh, wait—winter might be the perfect time to work on speed.
There is nothing revolutionary about that idea. Most training systems use the offseason to work on weaknesses, which could be speed for many trail runners. Too often, though, it’s tempting to think the winter is a time to hibernate like a groggy, well-fed bear. And it might be, especially if an athlete is feeling burnt out or run down. But aside from mental and physical recovery, there is no magic performance enhancement that happens from taking too much time off. Most of us will just spend the first few months in spring trying to catch up to our less sleepy-bear friends.
While everyone should use an individualized training approach, many of the athletes I coach use the wintertime to work on speed (and strength work), after adequate time off to recover (if needed). Last year, for example, Jason Schlarb got in fast 5K shape in February, which let him rock at ultras in summer. Keely Henninger was ready to hammer a 10K in January, and she used that speed to win the Chuckanut 50K and Lake Sonoma 50 in March and April. They rested when they needed to. But they didn’t let the winter go to waste.
On top of the physiological benefits, speed-focused training can be a fun variation that provides some purpose in the cold months.
Speed training improves running economy and can be fun
Focusing on speed improves running economy. My current favorite study came out in Physiology Reports in 2018. That study had 20 participants do 10 speed sessions over 40 days consisting of 10 x 30 seconds fast, while reducing overall training volume. The runners improved 10K performance by 3 to 4 percent. Coolest of all? Their vVO2 max improved by 2 percent while their VO2 max itself didn’t change, meaning that they were using less oxygen to go the same pace.
And the benefits can be rapid. A 2017 study in the Journal of Strength and Conditioning Research did a two-week intervention where 16 athletes did six speed sessions of 4 to 7 x 30 seconds fast. The athletes improved by 6 percent in a 3000 meter time trial and their maximum aerobic speed improved by 2 percent. Theoretically, these economy gains would lead to faster trail running too.
On top of the physiological benefits, speed-focused training can be a fun variation that provides some purpose in the cold months. A 2011 study in the Journal of Sports Sciences had a really cool finding: hard interval workouts may be perceived as more enjoyable than lower-intensity continuous runs.
That study had eight men do two workouts, one of 6 x 3 minutes at 90 percent of VO2 max with three minutes easy recovery, one of 50 minutes at 70 percent of VO2 max. Even though the first workout had higher perceived exertion, it had much higher ratings of perceived enjoyment (88 versus 61 on a scale involving a test with 18 7-point questions that I am really glad researchers did not administer to my wife after our first date).
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So getting fast can be effective and fun. How does a trail runner, used to lots of continuous miles, go about doing it? There are dozens of possible approaches, but I like beginner and intermediate athletes to do it in two phases, making sure you start from a place of physical health and mental excitement.
Remember: stay flexible in winter, and if you can’t find ice-free terrain and don’t want to use the treadmill, no need to push speed training at all.
Phase I: Getting used to going fast (speed endurance development)
The first phase usually lasts anywhere from four to six weeks, involving developing speed endurance on top of an aerobic base. After you have been running consistently and healthily for at least a month, do three sessions of fast, short strides per week (done on hills at first, flats later). One possible layout:
- Monday: rest
- Tuesday: easy run with 8 x 20 seconds fast/1 to 2 minutes easy
- Wednesday: easy run
- Thursday: easy run with 8 x 30 seconds fast/1 to 2 minutes easy
- Friday: rest or easy run
- Saturday: easy run with 10 x 30 seconds fast/1 min easy
- Sunday: slightly longer run over hills
Phase II: Going faster for longer (vVO2 and critical velocity development)
The second phase can go for most of the rest of the winter, involving using the speed endurance to access race-ready speed. One possible layout:
- Monday: rest
- Tuesday: easy run with 6 x 20 seconds fast/1 to 2 min easy
- Wednesday: workout, with intervals of anywhere from 1 to 5 minutes at 5K to 10K effort with anywhere from equal rest to half-time rest
- Thursday: easy run
- Friday: easy run or rest
- Saturday: slightly longer run with fartlek sections of 1 to 2 minutes in duration at 10K to 1-hour effort
- Sunday: easy run with 4 to 8 x 30 seconds fast/1 to 2 minutes easy
There isn’t any magic to that approach, it’s just meant to suggest what a simple setup could look like. Add strength work (and/or work with a physical therapist) for even more benefits. Mix it up, listen to your body and most importantly, prioritize loving the process.
You can use winter speed to unlock spring strength. ‘Tis the season for 5K PRs.
David Roche partners with runners of all abilities through his coaching service, Some Work, All Play. With Megan Roche, M.D., he hosts the Some Work, All Play podcast on running (and other things), and they wrote a book called The Happy Runner.