Does Running Build Leg Muscle? Here’s What To Know if You Want To Swap Leg Day for a Run

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Even if you’re not a runner yourself (yet!), you probably have a friend, family member, or coworker who runs. Along with hearing of the glorious tales of races and tough training runs from the enthusiastic runner in your life, you’ve probably noticed something else: Runners often have pretty muscular legs.

All the miles of training helps strengthen the lower body, namely the quads, glutes, hamstrings, and calves.

But, is running enough to build leg muscle? What happens if you want to swap leg day in the gym for a run? Will your legs still get strong? To find out, we spoke to Mindy Solkin, a USATF level 2 certified running coach and founder of The Running Center.

Experts In This Article

How does running compare to resistance training?

Although running does strengthen the muscles, it’s not necessarily the best way to build leg muscle. Traditional resistance training exercises like squats, deadlifts, step-ups, and glute bridges are generally more effective, especially if you use dumbbells or other weights. That’s because running only uses your bodyweight and the additional load when lifting weights helps better overload the muscles—which is what stimulates muscle protein synthesis, the process of muscle growth.

Because running is one repetitive motion that you perform over and over again, it can also create imbalanced strength, with certain muscles putting in overtime and others, well, not. Because of this, Solkin says that you should balance your running workouts with strength training exercises that work the opposing muscle groups so you can train all your leg muscles.

“It’s important to strengthen opposing muscles in synergy with each other,” she explains. “When doing calf raises for the gastrocnemius muscle, the runner should also do exercises for the anterior tibialis muscle (front of lower leg) to create more balanced strength on the lower leg to prevent injuries.”

Will running alone strengthen your legs?

If you’re wondering if just running will make you strong enough, Solkin says the answer depends on your goal. In other words, strong enough for what? Strong enough to run a marathon? Strong enough to squat 100 pounds? Strong enough to safely perform everyday activities?

Also know that the amount of leg strength you build by running depends on variables like the terrain you run on, the length and frequency of your runs, your speed, and your weight. “A person who runs three times per week on a flat course at a slow pace will not have as much leg strength as a person who runs six times per week on hills at a fast pace,” explains Solkin.

The type of running workouts you do will also influence whether your training will primarily increase muscular endurance or strength/power. “A marathon runner, who runs for multiple hours, has stamina, which is the result of strength multiplied by time,” notes Solkin. “A sprinter, who only runs for seconds, produces power, which is the ability to exert maximum muscular contraction instantly in an explosive burst of movements.”

No matter what kind of running you’re doing, though, strength training exercises will help you have a more powerful stride and may help prevent injuries and improve performance. Your strength workouts don’t even have to be particularly intense. For example, Solkin created Runditioning™, a strength and conditioning exercise program for runners. “Many of the exercises are done while standing on a balance board on one leg, while the other leg swings in a forward/backward stride, mimicking the running movement. I call this ‘running on one leg,’ which results in having balance, stability, and strength on each leg, independent of each other.”

One more thing: While runners put a lot of stock in the strength of their legs, you also shouldn’t neglect the rest of your body. “Remember that, although the legs and the core muscles do most of the work, it is important to strengthen your arms too,” says Solkin. “Having strong arms will help your form and will also help you run up hills more efficiently, taking some of the pressure off the legs.”

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