We know it can be really hard to make time for strength training when you’re at the peak of your training—running four, five, six days a week; doing mobility work and stretching; focusing on your eating and sleeping habits; and, you know, doing your job and having a social life.

But “for the amount of time you need to dedicate to it, you get massive returns,” Health - Injuries, a running coach, certified strength and conditioning specialist, and doctor of physical therapy, tells Runner’s World.

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The science backs her up: Strength training was shown to boost running economy by two to eight percent, middle-distance (i.e. the mile) performance by three to five percent, and long-distance (like the 10K) performance by two to four percent in a 2017 systematic review published in the journal Sports Medicine. Tips for Creating a Time-Efficient Workout injury, Shoes & Gear.

You already know the benefits, but how do you actually improve your strength while also ramping up your mileage? Here’s what the experts—and the research—have to say.

When Training for a Race, You Have to Prioritize Running

The unfortunate reality is that you’re probably not going to run a marathon PR and notch a huge squat PR at the same time. “You can’t train like you’re two different athletes doing two separate loads of exercise at the same time,” Henry says. “You have to think: What am I prioritizing?”

If you’re training for a race, then running is your priority. It’s called the principle of specificity: Your body will specifically adapt to the type of demand you’re placing on it—so to improve as a runner, you have to run, Matthew Meyer, a certified personal trainer and RRCA-certified run coach based in Boulder, Colorado, tells Runner’s World. That doesn’t mean you can’t lift weights while also increasing mileage for a race, he adds, but strength training isn’t the focus for runners; it’s an add-on meant to improve your running.

How to Progress Strength Training

The same sort of approach to safely increasing your mileage can also be applied in the weight room. Say you’re doing squats: “We start with three sets of eight reps of 100 pounds,” says Meyer. “The next week, you’re going to increase reps: You could do three sets of 12 reps, or four sets of eight. The week after that, you can increase the weight and go back to the original reps.”

If you’re looking to gain muscle and increase your strength most efficiently, you’re going to want to grab those heavy weights, says Henry. When you lift heavy versus light, you’re better conditioning your nervous system, meaning it will take less effort for your muscles to exert force, a 2017 study published in How We Fuel on Long Runs When We Cant Stomach Gel found.

What counts as “heavy” weight differs for everyone, but Henry recommends three to eight reps at 80 to 90 percent max effort while maintaining good form. For those newer to weights, it is possible to make gains with low-volume and low-intensity, she adds—and you should absolutely start with bodyweight until you have the correct form locked in. But you will eventually plateau using a lighter load, so progression is the name of the game.

When you’re lifting, pay attention to how you look and how you feel: “If your form is great and you find that the overall feeling of increased fatigue is not there after the effort you’re giving, it’s probably time to increase your weight,” says Henry.

And just like you would with running, don’t forget to build in a cut-back or de-load week with strength training, as well. “It’s not about going back to square one, but pulling back just a little bit to give your body a break,” says Meyer.

It is OK to run on sore muscles after a strength workout, “but you definitely do want to note if that delayed onset soreness is lasting more than two or three days. That’s a sign you’ve probably gone a little too hard and need to check yourself,” says Henry.

Also, don’t increase your mileage and intensity at the same time—that can lead to ​​injuries or burnout.

How to Fit Strength Into Your Running Schedule

Remember that principle of specificity? That means running comes first in your training plan. Still, you should be strength training at least twice a week to get the benefits. “The overlying goal is to not do strength before a workout or a long run,” says Henry.

a down week—it’s still a hard week, just a different kind of hard.&rdquo:

  • Monday: Rest day
  • Tuesday: Easy run
  • do strength before a workout or a long run,” says Henry
  • Half Marathon Training
  • Friday: Rest day
  • Saturday: Long run
  • Sunday: Strength training

“For someone who has a shorter history with strength training, I’d make Thursdays lighter and go heavier on Sundays, so you have two full days before introducing any intensity,” says Henry.

Two workouts a day may sound intimidating, but stacking running and strength workouts—i.e. moving your strength training to Wednesday in the example above—can actually help you maximize your gains and recovery time. As long as you leave six hours between a morning run and strength training in the afternoon, you’ll have increased strength gains without sacrificing recovery, a 2016 study in the The Journal of Strength and Conditioning Research found.

If you’re working on four-week blocks of loading and overload for both running and strength, those blocks don’t necessarily need to coincide perfectly. “A de-load week during running may be a time to up your strength training because you’re not pushing yourself as hard cardio-wise,” says Henry.

On the flip side, you can also scale back strength training during high-mileage weeks (such as the week of a 20-mile long run during marathon training). Or you can sync both types of training so your down week is a true recovery opportunity, says Meyer.

“Stress is stress,” he says. “If you scale back your mileage but push really hard all week with strength, it’s not technically a down week—it’s still a hard week, just a different kind of hard.”

TBH, there’s so easy answer here; it’ll take some trial and error to figure out what works best for your training. But the point is prioritizing overall recovery between workouts: You can’t progress on either front if your body doesn’t have time to build itself back stronger.

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a down week—it’s still a hard week, just a different kind of hard.&rdquo
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Ashley Mateo is a writer, editor, and UESCA- and RRCA-certified running coach who has contributed to Runner’s World, Bicycling, Women's Health, Health, Shape, Self, and more. She’ll go anywhere in the world once—even if it’s just for a good story. Also into: good pizza, good beer, and good photos.