Runners aren’t exactly known for being the most muscly folks in the gym. But considering any exercise is better than no exercise, it’s natural to wonder: Does running build muscle?

It certainly can—but it’s not the most direct path to more defined quads or stronger glutes. Here’s what to know about the muscle-building effects of running and how to maximize your gains.

Does Running Build Muscle?

It’s not exactly a satisfying answer, but the truth is, it depends.

If you run regularly and perhaps also engage in other types of workouts, running isn’t your best bet for increasing muscle mass and size (also known as hypertrophy). To truly see changes in your muscle strength and size, you’ll need to focus on a dedicated strength training routine.

“Running is great for your cardiovascular health and maintaining a balanced level of overall fitness, but it’s not an effective way to build muscle,” says Peloton instructor Erik Jäger. “If muscle growth is your goal, there’s no way around it: You need to lift.”

However, if you’re not as active, you may build some muscle from running. “If you’re relatively untrained and focus on interval training or sprint workouts, you might see an increase in muscle mass,” Erik says. For example, some small studies have shown that aerobic exercise can be as effective as strength training in building muscle in certain groups of people, such as older adults.

It’s also worth noting that, because running is primarily a cardiovascular exercise, it can reduce body fat. And when you have less body fat, you may notice your muscles become more visible. “This increased visibility of the muscles can give the impression that muscle mass has been built, when in fact it’s mostly about definition, not hypertrophy,” Erik says.

Exactly How Running Builds Muscle

Most running workouts build a specific kind of muscle fiber called type 1 or slow-twitch fibers, according to the National Academy of Sports Medicine (NASM). “These types of muscle fibers are activated during endurance activities like long-distance running,” says physical therapist Raquelle Felder, owner of San Diego Mobile Rehab and Physical Therapy. Training these slow-twitch fibers builds lower-extremity strength for specific endurance sports, Felder explains—but they typically aren’t the major players behind visible gains in muscle size. 

Type 2 or fast-twitch muscle fibers, on the other hand, grow in size much more easily, according to NASM. They’re the muscle fibers responsible for short, powerful movements. Certain types of running, including higher-intensity sprinting and interval running, will build those fast-twitch muscle fibers, Felder says. This likely still won’t deliver as impressive results as lifting weights, but “muscle adaptation is achievable with running as you increase intensity or duration, and as you progressively challenge yourself with your training,” she says.

Key Muscles You Engage and Strengthen While Running

Running challenges a number of different muscle groups—and not just in your lower body. The muscles worked by running include your:

Which Running Workouts Should You Do to Build Muscle?

Picture the last time you watched track and field at the Summer Olympics or another high-profile running event. Sprinters are often much more visibly muscular than long-distance runners, Erik says. “To actually build muscle through running, sprint and interval training are the way to go,” he says. “That said, it’s important to note that most sprinters also do a lot of strength training on top of their running workouts.”

Still, sprint workouts and interval training are challenging enough on your lower body that they may build some noticeable muscle there. “These workouts not only push your cardiovascular system but also activate and challenge your fast-twitch muscle fibers—essential for muscle growth,” Erik says. 

Try either of these muscle-building running workouts below, or cue up a guided outdoor run or guided treadmill class on the Peloton App to have an instructor coach you through it.

Hill Sprints

Also called hill repeats, this challenging training technique involves running up a hill—over and over again.

Interval Repeats

There are a lot of different ways to do internal training while running. If you’re near a local track, try this interval running workout. 

Tips to Keep In Mind for Maximum Gains from Running

If your goal is truly to build muscle, you’ll need to keep a few pointers in mind for your running workouts, the rest of your fitness routine, and the healthy habits that support your exercise efforts.

Prioritize Strength Training

For starters, you should really be doing more strength training than running if you truly want to see visible muscle gains, Erik says. “For example, if you’re running three times a week for 60 minutes each, you should be strength training more than three times a week to see real muscle-building effects.”

Focus on compound exercises that work more than one joint and muscle group at a time, such as squats, lunges, and deadlifts, Felder says. “Compound movements help with function and power output for running.”

You can lift weights on the same day as a run. Just make sure to do your cardio after your strength sessions to keep the priority—and energy focus—on muscle growth, Erik says.

Vary Your Running

It’s always a good idea to have some variety in your training routine to “promote longevity and prevent injury and boredom,” Felder says. But runners looking to build muscle can also reap different muscle-building benefits from different types of running workouts, she says.

Make sure you have sprint workouts, high-intensity interval training (HIIT), and hill intervals sprinkled throughout your running schedule. “Try integrating different types of workouts with short bursts and incline training to train all muscle groups and fibers,” she says.

Fuel Your Workouts Properly

Nutrition is always important for fueling muscle growth, but it becomes even more important when you want to build muscle while running too. “Running increases your caloric expenditure, which means your body has less energy available for muscle growth unless you compensate through your diet,” Erik says.

You’ll likely need to eat about 300 to 500 more calories than what you’re burning each day, Erik says. “Under-fueling causes fatigue and muscle breakdown and hinders performance,” Felder adds. “You simply feel better when you give your body what it needs to function optimally.” 

You can’t build muscle without eating plenty of protein; aim to eat around 1.4 to 2.2 grams of protein per kilogram of your body weight each day. (To find your weight in kilograms, divide your weight in pounds by 2.2.) Spread your protein throughout the day so your body can use it more efficiently.

But don’t skimp on carbohydrates, either. “Protein is essential for muscle repair, but carbs provide the energy your body needs for intense strength sessions and recovery,” Erik says.

And finally, “stay hydrated throughout the day and with electrolytes during or after exercise,” Felder says.

Stay Consistent

Building muscle takes time and a persistent, intentional effort, whether you're aiming to do so with running or any other type of exercise. “Consistency is key,” Felder says. “Show up for yourself and your goals every day, through training, recovery, and nutrition.”

Consider joining a local running group if you could use some accountability or work with a running coach or other fitness professional for more support reaching your goals, she adds. “You don’t have to stay consistent alone. We are all rooting you on!”

You can also find strength training and running programs on the Peloton App and Peloton Strength+ to help keep you accountable, motivated, and engaged. 

Remember to Rest

And even though you’ll be keeping pretty busy with your cardio and strength routine, you need at least one full rest day from exercise each week and quality sleep every night.

“[Sleep] is when your body releases growth hormones, which are essential for muscle repair and growth,” Erik says. Aim for 7–9 hours each night, according to the National Heart, Lung, and Blood Institute, and set yourself up for success with healthy sleep hygiene. “Make sure you’re doing what you can to optimize your sleep quality. A consistent bedtime, a cool, dark room, and limiting screen time in the hour before bed can go a long way,” Erik says.

On active recovery or rest days, think about what your unique body needs. “Recovery may look different to different people and at different times,” Felder says. “Think of a recovery day as a mind-and-body reset. Try a nice hot bath, gentle movement that feels good in your body, deep breathing exercises, and meditation for a full reset.” You can follow along with lots of restorative options like guided meditation classes and yoga classes on the Peloton App. 

The Takeaway

Running builds some muscle, but not as much as strength training. If you really want to build muscle from running, make sure you’re incorporating sprints, hills, and HIIT workouts into your running routine, alongside several strength-training workouts per week. Stay consistent and accountable to your training plan for the best results. Prioritize nutrition, hydration, and recovery, and you’ll see noticeable gains in time.