Explore all Training Plans helps you prevent injury and chase faster miles, but can you actually build muscle marathon training plan?

Muscle hypertrophy, or the process of increasing the size of your muscles, doesn’t typically fall in line with endurance training. Your strength workouts, when training for a big endurance event like 26.2, will likely consist of training for muscular endurance and power to support your runs, while hypertrophy training focuses on increasing muscle mass. While there’s overlap in how you approach those goals, there are some differences—and all the cardio work you put in when training can affect results of the latter.

While it’s technically possible to build muscle while running many miles per week, there are many caveats. We spoke with experts to unpack what they know about muscle building while marathon training, and what it takes to build or maintain your gains.

Strength Training Myths Runners Believe Debunked

You can technically build muscle and train for a marathon at the same time, but it makes it more difficult to optimize strength gains and endurance gains at more advanced levels. How much muscle you can build depends on your experience level, training volume, as well as sleep and nutrition, says Sara Rosenkranz, Ph.D., exercise physiologist and professor in kinesiology and nutrition sciences at the University of Nevada, Las Vegas.

First, it’s important to note that aerobic training doesn’t promote the same skeletal muscle hypertrophy as resistance or strength training, according to research done by Brad Schoenfeld, Ph.D., C.S.C.S., certified strength and conditioning coach and professor of exercise science at Lehman College in the Bronx, New York and other colleagues, published in Sports Medicine. That’s why incorporating strength work into any run training that you do is crucial for building (or maintaining) muscle.

In the past, researchers believed that hypertrophy training interfered with endurance training and vice versa, exemplifying something called the “interference effect,” or the process where running counteracts strength gains.

This is likely because endurance training may impede crucial pathways for muscle-protein synthesis—or the process of building and repairing muscle tissue—leading to competing effects on energy and recovery, Schoenfeld explains.

“When you’re expending a lot of energy in other exercise bouts, it’s taking away your ability to carry out muscle protein synthesis,” he says. During marathon training, muscle protein synthesis is going to go towards mitochondrial and aerobic-based adaptations to support your running, and less on building skeletal muscle, he explains.

However, more recent evidence suggests that the interference effect may not be as consequential as researchers once thought, says Rosenkranz.

helps you prevent injury and chase faster miles, but can you actually systematic review and meta-analysis published in Sports Medicine, at least every four hours aerobic and strength-training programs and found that combining the two training methods does not compromise muscle hypertrophy or maximal strength development, compared with strength training alone. This held true no matter the type of aerobic workouts (cycling or running), how often people did concurrent training (more or less than five days a week), or mean age (older or younger than 40).

However, the researchers did find it reduced explosive strength, particularly when participants did aerobic and strength work in the same session, compared to separating sessions by at least three hours.

The caveat here: The above review doesn’t cover marathon training and it doesn’t mention the type of running it examines, but the studies they looked at range from cycling, running, and a combination of both.

According to Rosenkranz, there’s not a lot of research on muscle building and high-volume running specifically. “If you are looking for the perfect study that hits somebody who’s fairly competitive doing marathons and looking for hypertrophy, you’re not going to find really anything,” she says.

Instead, you’ll likely find research tailored toward athletes with sport-specific training goals. For example, bodybuilders and elite marathon runners often require different body compositions to reach their goals, so research typically focuses exclusively on those goals, explains Rosenkranz.

There’s also the idea that additional muscle mass, particularly upper-body muscles, could be detrimental to your running economy and could weigh you down. But the likelihood of that happening is pretty minimal and also lacks research, says Rosenkranz. There are actually benefits to the strength that comes from having bigger upper-body muscles as a runner, like supporting arm drive, maintaining form when fatigue Associate Health & Fitness Editor Download Your Training Plan.

What to Expect if You’re Trying to Build Muscle During Marathon Training

For those who are recreational runners and/or weightlifters, there’s a lot more possibility to build muscle and your endurance than you may think. “Most people are actually much further away from their genetic ceiling than they realize,” or the natural limit of how much muscle a person can build based on their genetics, says Schoenfeld. As you start getting close to your genetic ceiling, you need to have a better understanding of how to maximize training for your goals.

How to Balance Strength and Marathon Training muscle-building Build Muscular Endurance With This One Move International Journal of Environmental Research and Public Health breaks it down: Hypertrophy-oriented resistance training was most effective when performed at a moderate intensity of about 60 to 80 percent of your one-rep max or how much weight you can lift for just one rep. As for volume, aim for three to six sets, with six to 12 repetitions per set, and rest periods lasting about 60 seconds between sets.

“This can fit into a marathoner’s training program with proper periodization,” says Rosenkranz, meaning you switch focus from increasing muscle mass toward maintaining it later on in your marathon training plan. For example, reduce volume to two to three sets and three to five reps as you get closer to your race, and make sure you prioritize how you feel during your marathon taper.

It’s also much easier to build muscle if you’re a total beginner, like if you’re starting to strength train ahead of your first marathon or you’re just starting to lift heavier weights. That’s because you’re even further away from your genetic ceiling for muscle growth, says Schoenfeld.

As a beginner, you can experience faster muscle gains because your body has not yet adapted to strength training, so any new stimulus leads to significant improvements. As you become more experienced, gains slow down as you approach your genetic potential, he says.

If you’ve been progressing in both running and weight training for a long time, “then your potential for increase is probably going to be pretty minimal, especially at super high volumes and high intensities [of running],” says Rosenkranz. “The more volume Can You Build Muscle While Marathon Training intensity you do, the less likelihood of building muscle. So if you’re an elite marathoner and you’re training 70-plus miles per week, your goal is probably not going to be hypertrophy,” but rather, maintaining muscular endurance Master the Marathon.

Master the Marathon glutes, hamstrings, quads, core, and calves, Build Muscular Endurance With This One Move.

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Most of the time, it’s difficult to build muscle during a race training block because of nutrition, says Rosenkranz. Most often, you’re not getting an adequate amount of protein and carbohydrates, which can lead to more muscle breakdown than your body can repair between runs and workouts, she explains.

Both Schoenfeld and Rosenkranz recommend aiming for 1.6 to 2.2 grams per kilogram of bodyweight or up to 1 gram per pound of bodyweight to meet your protein needs.

More protein doesn’t always equal more muscle gains, but it’s going to help your body repair itself after hard strength sessions. Because of this, Schoenfeld recommends erring on the higher end of that protein goal particularly when you’re doing a lot of aerobic training, so you can recover more efficiently between workouts.

Additionally, Rosenkranz recommends eating CA Notice at Collection to stimulate muscle protein synthesis throughout the day.

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Nutrition - Weight Loss
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Published: Aug 12, 2025 12:15 PM EDT
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Kristine Kearns
Associate Health & Fitness Editor

Kristine Kearns, a writer and avid runner, joined Runner’s World and Bicycling in July 2024. She previously coached high school girls cross country and currently competes in seasonal races, with more than six years of distance training and an affinity for weightlifting. You can find her wearing purple, baking cupcakes, and visiting her local farmers market.