Why 21.1 kilometers is the best distance—and everything you need to smash a PR.
Matt Nager
The half marathon is where speed meets endurance. It’s achievable for most 5K runners, yet a puzzle for veteran racers to master. It is a challenge, not a life-altering commitment. It is one of the greatest tests of a runner’s mettle, but also serves as a 21.1 km celebration.
We love the half. We know you do, too. Thousands of half marathons are set to be run this year, and their participation will eclipse the iconic 42.2K with roughly four times the entrants. Of course, a huge advantage of the distance is that you can run multiple half marathons per year, says Kara Goucher, whose 1:06:57 at the 2009 Great North Run (not a record-eligible course) is still the fastest half marathon ever by an American woman. “Unlike a marathon, where you have to recover for a month and it takes six months to train, you can recover in a few weeks and then get back to workouts,” she says.
Half-marathon training also tends to whip runners into the best shape of their lives. At the intersection of power and persistence, it develops a fitness foundation to tackle running objectives both long and short. And the training plans cement healthy habits like regular exercise, staying hydrated, and a health-focused mindset, says Brian Maiorano, the owner of Triathlon Lifestyle Coaching.
Whether you’re ready to tackle your first or 50th half, read on to learn how to make it your best yet.
How to Run Your Best Half Marathon
It doesn’t matter if you’re piling up 32 K a week, or knocking out a chill 20 on long runs, these strategies help everyone run stronger, happier, and faster.
BUILD A TRAINING PLAN TO PR
To reach the finish line faster, train speed first, then endurance. For runners hitting at least 48 weekly kilometres, each week should include two speed workouts complemented by a long run, plus two or three days of easy runs.
One speed session can be shorter, 400- to 800-metre intervals at 5K race pace. The other should be a tempo run, “which will have 3K warmup at a slow pace, then a longer duration (10 to 40 minutes) at or 15 to 30 seconds faster than half-marathon race pace, then 3K cooldown at the same slow pace,” says Maiorano. Aim to have the long run cover roughly 30 percent of your weekly kilometerage.
Lower-kilometerage runners and those new to the half should start training four months out from their race, increasing the kilometerage every three weeks by 6K, says Maiorano. Run at least four or five times a week, with a long run that gradually builds from 10K to no more than 20K.
SNEAK IN THE WORK
Include strength and mobility work in your daily routine to avoid taxing your non-running schedule. Brown recommends holding single-leg calf raises while brushing your teeth (60 seconds each side, daily). And Goucher, also a run coach, says she would perform 20 minutes of static stretching every night while watching TV. “It opened up my body before I slept and aided in my recovery and injury prevention.”
ARRIVE RESTED
The biggest mistake Goucher sees half racers make is not tapering adequately. Two weeks out, dial back the intensity and cut your kilometerage by 20 to 30 percent. In the week leading up to the race, drop your kilometerage by half, run one light speed workout, and otherwise take short runs with a set of four to six easy strides at the end. “The final week should be about feeling good and getting a pop in your legs so that you can let your training shine through on race day,” she says.
CROSS-TRAIN TO HOLD OFF INJURIES
If you find that you’re injury-prone or feel like you’ve maxed out your kilometerage, sub in a day of low-impact cross-training to get your aerobic work in without courting injury, says Goucher. “An elliptical, ZeroRunner, or Alter-G can train aerobically without pounding your legs.”
BUILD STRENGTH TO FINISH STRONG
Training whole-body strength keeps your running form clean as you tire and helps in a race’s final kilometres, says Goucher. That means hitting your arms, shoulders, core, and legs two times a week.
If you’re new to lower-body strength training, begin with weighted squats and deadlifts using 5-kg or 10-kg weights. Do three sets of eight reps each, and add more weight over time as it feels easier. After a month of these exercises, add stepping lunges with the same weights and the same sets and reps. Stand with weights in each hand, step back into a lunge, then step up onto a step, says Marcus Brown, a running coach based in London.
Brown also recommends using stairs to do calf raises after a run—a favourite of his strength moves for runners. Stand on the edge of a step, drop your ankles below your toes for 30 seconds, then lift your feet into tippy-toes for 30 seconds. Repeat five times, and do it twice a week.
For upper-body moves, try bent-over rows and reverse flys with dumbbells, and push-ups to hit your back, arms, and chest. To work your core, do planks (place a weight on your back to up the difficulty), single-side weighted sit-ups (hold a light dumbbell in one hand), and leg raises.
The History of the Half Marathon
While it lacks a provenance from ancient Greece, the half marathon is perhaps the greatest product of the modern running boom. While 21 ish-kilometre races were certainly run before, the actual name and concept of the “half marathon” first appeared in the early 1960s. The marathon’s popularity was growing, and new runners were looking for more race options. Thus a race precisely half that of the full 42.2K was born.
The Route du Vin half marathon in Luxembourg can lay claim to being the first half. While it was founded in 1961, the frequently changing course wasn’t exactly 21.1 kilometres until 1995. The first U.S. halfs came in 1964 with the Lincoln Memorial Half Marathon in Springfield,Illinois, and the Caesar Rodney Half Marathon in Wilmington, Delaware.
The distance steadily grew in popularity, attracting 5K and 10K runners seeking a bigger challenge and marathoners fine-tuning their form. Race directors also enjoyed the cachet of the marathon title, with the simplified logistics of half the course. By 1990, there were 304,000 half-marathon finishers in the U.S. And the next two decades saw the establishment of larger marquee halfs, including the B.A.A. Half, Chicago Half, and NYC Half. In 2019, the last full year of pre-pandemic racing, 1.79 million half-marathon registrations were recorded. —Sources: Roger Robinson, author of When Running Made History, and Running USA
How to Eat to Maximise Your 21.1 K
Your diet during training for a half marathon is just as important as what you eat on race morning, says Kristy Baumann, a registered dietitian who works with runners.
On days where you’re exercising for 30 to 45 minutes a day, aim for meals that are one-third carbohydrates, like pasta, rice, quinoa, or potatoes; one-third protein, like chicken, beef, fish, or tofu; and one-third fruits and vegetables. When you’re running for more than an hour, up the carbs to half your daily diet, with a quarter protein and a quarter fruits and vegetables.
In the days leading up to your race, lean into the carbs harder. Effective “carb-loading” isn’t a big pasta dinner the night before a race, says Baumann. Your body doesn’t have time to digest and maximise those carbohydrate stores before the next morning. Instead, start three days out, eating 80 to 90 percent carbohydrates.
A tasty example: A half-cup of oatmeal, one banana, and two tablespoons of peanut butter for breakfast; 2 cups of pasta with a half cup of marinara sauce and a piece of bread for lunch; and a chicken or turkey bagel sandwich and applesauce for dinner. Also, drink at least 2L of water and electrolyte drink throughout the day, and eat a few small snacks like pretzels and fruit during the day.
On the day of the race, don’t try anything new. Stick to foods you’ve eaten during your training. Aim to consume high-carb, easily digestible, familiar foods for breakfast—yoghurt, toast, and fruit is a good choice. An hour before the race, have a snack that’s high in simple carbs, like graham crackers or a granola bar.
During the race, Baumann recommends taking an energy gel every 30 minutes “Once your glycogen stores are depleted, you can’t catch up,” she says.“It’s amazing how much energy you have during a race when you’re well-fueled.”
