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The Ultimate Guide to Running 100K

If you’re going to run in the dark, let’s make it as fun as possible.

Heather Balogh Rochfort

December 14th, 2022

6 min read


Photo from Waldo 100K – Oakridge, OR

By diving into a 100K race, you’re making a proclamation: you’re ready to go big. The 100K distance is often considered the “gateway” to the 100-mile distance. Even if you don’t intend to go farther, you’re still going to put in some work. For many runners, this will be the first time you’ve intentionally committed to running after dark, and it’s a big step.

So, let’s treat it like one. We connected with a few of our favorite coaches and asked them to share their favorite 100K training advice to better prepare you for the big dance. Regardless of whether you’re a first-timer hoping for a happy finish or an experienced pro going for a shiny PR, we’re confident we’ve got some good tidbits to get you to that starting line healthy, happy, and ready to race.

Plan Your Training Schedule

For those of you go-with-the-flow runners, this one may hurt but it’ll feel much better come race day. Heather Hart, UESCA certified ultrarunning coach and owner of Hart Strength and Endurance Coaching, recommends following a training plan specifically written for you by an experienced and educated coach. If that’s not in the financial cards, find a good one from a reputable source. “A properly programmed training plan will help ensure that you are building up the running volume needed to successfully complete the 100K distance, but doing so in a safe way that helps you avoid injury or burnout,” she says. 

And it’s a good idea to incorporate plenty of racing experience into your training. Laura Swenson, personal trainer and running coach with more than 20 ultramarathons under her waistbelt, suggests running a few 30-50K races as benchmarks during training, and specifically tackling a 50K two to four weeks prior to your big race. Not only will this help you work out the kinks, but it will help you overcome race-day anxiety, she notes.

Adjust to the Dark

Kids and adults alike agree: there’s something inherently spooky about the dark. That’s why it takes some time to get used to the idea of willingly running through the inky night. Swenson notes that most runners will need at least 12 hours (or more) to finish their 100K, so finding your feet when you can’t see them is going to be a must. During your practice runs, she recommends a headlamp or waist lamp with good battery life and at least 100-800 lumens of light. Pro tip: “Don’t forget a spare battery, even while training,” Swenson says. “After a few hours in the dark, the light always starts to dim—and there is always a chance of malfunction.”

Find Your Fueling

We know it’s important to find a fueling strategy that works for your body. If you’re running a 100K, chances are good that you’ve already found that system. But here’s the caveat: don’t be scared to expand your horizons. “If you get attached to one type of fuel, you’ll get sick of it—trust me!” says Swenson. She suggests mixing liquid carbs (in your water or gels) for quick energy along with “real” food such as peanut butter and jelly sandwiches or boiled potatoes. Don’t forget the treats, either. If it looks good at 10am on a Thursday, it may look downright delicious when you’re 50 miles out. “I like sour cherry balls for a parched mouth and gummy worms,” Swenson says. No matter the treat, be sure to try it out at least once before race day. “Begin practicing race day needs from the very beginning of your training cycle,” Hart advises. “By starting sooner rather than later, you’ll have plenty of time to really nail down what works well for you.”

Dodge the Burnout

Running 62 miles takes some time, but you know what takes even longer? Training to run 62 miles. That’s why burnout is very real during ultramarathon training. We barely know each other but we can still promise there will be at least one morning you wake up and think, “I really don’t want to do this today.” And that’s okay; that’s normal. But if burnout continues to plague your training, consider shaking up the miles. “While it’s ideal to train on terrain similar to that of your race as often as possible, you don’t always have to do this,” says Hart. “If running a certain trail or cruising with a local training group brings you joy, include that some of the time” 

And if variety isn’t the spice you needed in your life — try bribery. Swenson recommends incentivizing your training with special treats like a massage or new shoes when you hit particular milestones. You’ll be so focused on that hot stone massage that you may just forget how many miles you logged this month.

Avoid Injury

We know, it’s easier said than done. But staying healthy is the single most important aspect of your 100K training. While you can’t avoid all injuries, you can take preventative steps to sidestep the vast majority of them. First and foremost: sleep. “Sleep is an integral part of the healing process, as our bodies secrete higher levels of hormones responsible for tissue healing and hypertrophy while we sleep,” Hart explains. Prioritizing sleep and rest periods will not only maximize your recovery and healing, but it will also increase your body’s adaptation to the training. 

And, don’t be the runner who only runs. Specificity is important when running a 100K, but it’s critical that you adequately strength train so that your body can handle the strenuous load. Not only does this prevent overuse injuries by strengthening muscle, ligaments, tendons, and bones, but it also addresses individual weaknesses that contribute to poor running biomechanics, Hart explains. How often should you pump iron? Swenson suggests at least 2-3 times per week with at least one session focused on heavy lifts.

Let’s get swole.

11 thoughts on "The Ultimate Guide to Running 100K"

  1. lisa l Smith says:

    is there a 50k running guide?

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