Does Running Build Muscle?

There are lots of different ways to exercise, and each one is beneficial. You can lift weights to build muscle and get stronger, ride an exercise bike to get fitter and burn fat, or do yoga for better flexibility and balance. You don’t even need to choose between these activities, as they are very compatible with one another.

But what about running? Is that a good fitness option?

Running is arguably the original workout. People have been running for about as long as they’ve been on planet Earth. Initially, humans ran for transport, so they could get from point A to point B more quickly. As methods of transport changed, people started running less out of necessity and more for enjoyment. They also ran for health and fitness benefits.

As workouts go, running offers many advantages over other types of exercise. You can run almost anywhere and anytime, and all you really need for running is a decent pair of supportive, shock-absorbing shoes.

You can run for fitness or fat loss and, if you want more of a challenge, train for something like a five or 10K, or even a marathon. You can also run competitively.

But does running build muscle?

In this article, we reveal whether running is enough to build bigger, stronger muscles.

Is Running Good for Muscle Building?

In simple terms, running is NOT a good way to build muscle. While your legs will get a little bigger and stronger when you first take up running, any size and strength increases will a) happen quite quickly and b) be relatively small.

Your muscles are made up of two main types of fibers – type 1 and type 2b.

Running is primarily an aerobic activity that uses type 1 fibers. These fibers are red in color, have an excellent blood supply which means they’re good for endurance activities, but they do not have the capacity to get much bigger or stronger.

Type 1 fibers DO grow, but not much.

In contrast, type 2b fibers are white, have a poor blood supply, fatigue quickly, generate more force, and have more growth potential. Lifting weights preferentially targets type 2b muscle fibers, whereas running has minimal impact on them.

Because running does not really affect type 2b muscle fibers, it is not a good exercise for building bigger muscles. The only type of running likely to result in significant increases in muscle size is sprinting.

Sprinting is a high-intensity exercise that comes close to strength training for targeting type 2b muscle fibers. However, sprinting doesn’t have much of an impact on your cardiovascular system as it’s mostly anaerobic.

What Muscles Does Running Work?

Running is a surprisingly complex activity that involves a great many muscles. Pretty much every muscle in your body works when you run. That said, the primary muscles used during running are:

woman runningQuadriceps – located on the front of your thighs, the quadriceps are actually four muscles; rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. The quads work together to extend your knees and flex your hips.

Hamstrings – opposing the quadriceps, the hamstrings are responsible for flexing your knees and extending your hips. The three hamstrings are the biceps femoris, semimembranosus, and semitendinosus.

Iliacus and psoas major – collectively known as iliopsoas, these muscles work together to flex your hips.

Gluteus maximus – working with your hamstrings to extend your hips, the gluteus maximus or glutes for short is the largest muscle in the human body and is basically your butt.

Adductors – the three adductor muscles are longus, brevis, and magus, meaning longest, shortest, and biggest. Located on the inside of your thighs, these muscles draw your thigh in toward the midline of your body, which is a movement called adduction.

Abductors – located on the outside of your hips and thighs, the abductors include gluteus minimus and medius and tensor fascia latae. These muscles work together to stabilize your hips as you transfer your weight from one leg to the other.

Triceps surae – the collective name for your two calf muscles, the gastrocnemius, and soleus, the triceps surae are responsible for extending your ankles in a movement called plantar flexion.

Core – your core stabilizes your spine and ensures that your midsection doesn’t collapse while you run. The main core muscles are the rectus abdominis, obliques, transverse abdominis, and erector spinae.

Will I Lose Muscle If I Do A Lot of Running?

Initially, running will slightly increase muscle size and strength. That’s because your body responds positively to the stress placed on it and, to help you run faster and more efficiently, your muscles adapt to the workouts you are doing. Because the stress on your muscles during running is relatively low, there is no real need for your body to respond by significantly increasing muscle size or strength.

However, as you start to run longer and more often, you may actually begin to lose muscle. Not from your legs but from your upper body.

In an effort to increase running efficiency, your body will start dropping excess muscle. This is like trimming weight from an airplane or racing car to improve performance.

If you want to run but avoid losing muscle, you need to supplement your workouts with strength training.

What Is the Best Way to Build Muscle?

If you are serious about building muscle, running is not the best workout for you. Instead, you need to overload your muscles with strength training exercises to target those all-important type 2b muscle fibers.

This doesn’t mean you need to stop running or take up bodybuilding or weightlifting. However, you do need to engage in regular strength training.

Good exercises for building muscle include:

Lower body:

Upper body:

2-3 full-body strength workouts a week should be sufficient to build muscle while leaving plenty of time and energy for running.

Any type of strength training will work, including lifting barbells, dumbbells, or kettlebells, using resistance machines, doing bodyweight exercises, or working out with resistance bands.

Bottom Line

The best way to get results from your workouts is to align your training to your fitness goals. This is called specificity. Your body will adapt to the stresses placed upon it, so if you want to be a better runner, you need to do plenty of running.

Your body will make changes according to the workouts you do.

With running, this means increasing your cardiovascular fitness, muscular endurance, and ability to utilize fat for fuel. You WILL experience some minor increases in strength and muscle size, but these are not the main changes your body makes to help you run faster or further.

In contrast, if you lift progressively heavier weights, challenging your muscles in the process, they will get bigger and stronger. It’s like an immune system response; your body will get stronger to protect itself from future workouts.

The demands of running and strength training are very different, and it’s those differences that determine how your body responds to your workouts.

If all you do is running, you may actually lose muscle to help lighten the load so you can run further and faster using less energy. On the other hand, if all you do is strength training, your muscles will get bigger and stronger, but your cardiovascular fitness won’t increase much.

Use the right tool for the job; run for fitness and lift weights for muscle strength and size. Match your workouts to your fitness goals to get the best possible results from your training time and energy. Visit the Fitness Equipment Reviews homepage for more expert information and advice.


Patrick Dale is an ex-British Royal Marine and owner and lecturer for a fitness qualifications company. In addition to training prospective personal trainers, Patrick has also authored three fitness and exercise books, dozens of e-books, thousands of articles, and several fitness videos.

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