Does Running Make Your Calves Bigger? Here's What You Need to Know

When you think of building muscle mass, you might envision long, tedious hours spent in the gym lifting weights. But you can also grow your muscles by running — yes, even smaller muscles like your calves.

Located on the back of your lower legs below your knees, your calves are a two-headed muscle group consisting of the gastrocnemius and the soleus. The gastrocnemius is the larger of the two and makes up the bulging shape of the calf. The soleus is seated deeply in your calf under the gastrocnemius.

With every step you take, your calf muscles are working hard to propel you forward by lifting your heel when your leg is both straight and bent. So, the more you run, the more they'll work and the bigger — and stronger — they'll become.

So, does running make your calves bigger? And if so, what type of running is best? Ahead, we'll dive into what you have to do to build muscle mass and how running — and strength training — can help grow your calves.

When muscles increase in size through exercise, it's called muscle hypertrophy. The primary goal of muscle hypertrophy is for your muscles to get bigger, rather than for your muscles to get stronger, per the International Sports Sciences Association (ISSA). That's not to say your muscles ‌won't‌ get stronger during the process though!

Your muscles grow when they're stressed enough to break down, causing microtears, according to University Hospitals. When your body repairs these microtears, your muscles grow back bigger (and stronger).

While running doesn't break down your muscles to the same degree strength training does, logging miles does still cause microtears — specifically in your legs.

Now that we've covered how to grow your muscles bigger, we can answer the question: Does running increase your calf size?

The type of running you do — distance running or sprinting — makes a difference when it comes to building calf muscle size. That's because each type of running recruits one of two types of muscle fiber — slow-twitch or fast-twitch — each of which has a different result in the size of your muscles.

You use slow-twitch muscle fibers when you run long distances, according to the National Academy of Sports Medicine (NASM). These fibers aren't as strong as their fast-twitch counterparts (more on them below), but they can work for long periods of time without fatiguing due to their good oxygen supply.

Fast-twitch muscle fibers, on the other hand, come in handy when you're doing more explosive movements — like sprinting — per the NASM. That's because fast-twitch fibers are stronger than slow-twitch fibers. However, fast-twitch fibers do tire faster, so it's harder to sustain these efforts over a long period of time.

Due to the extraordinary amounts of explosive power required to sprint short distances, the calf muscles of short-distance runners tend to be large. In addition to sprinting, running up hills, doing plyometric drills (like hopping and skipping) and performing calf-specific strength exercises (like the moves below) all rely on your fast-twitch muscles and will build muscle mass in your calves.

While you may wish to shape your calves to suit your preferred running distance, focusing solely growing your calves may be detrimental to your goals. Your exercise program should combine muscle-strengthening and cardiovascular exercise, according to the Centers for Disease Control and Prevention (CDC).

Similarly, your calf workouts shouldn't focus exclusively on either bulking or toning exercises. For distance runners, the added power provided by resistance exercises may help on uphill climbs and race-closing sprints, while the endurance provided by long-distance running may benefit sprinters who compete in multiple races over a short span of time.

Is running good for your calves? In short, yes. But while running is helpful for building bigger, stronger calves, you can do strength exercises that help grow this muscle, too. Here are a few to add to your routine, according to the ISSA.

For best results, do 4 to 5 sets of 6 to 12 reps of each exercise.