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Running obviously builds your endurance. While one mile (or five miles) might feel really hard when you first start running, those distances become much easier the more you get out there.
Older Athletes’ Secrets to Running Longevity hills How to Build Muscle as a Runner finishing kick, heart rate max.
But does running build muscle? Can you change your body composition simply by clocking more miles?
The short answer is yes. But there’s more to the story. Here’s what to know about running and its affect on muscle mass.
The Mechanisms Behind How Running Builds Muscle
Research shows running can produce muscle growth. For example, a 2015 research review, published in the journal Exercise and Sport Sciences Reviews, found that aerobic exercise can increase skeletal muscle and whole muscle size, particularly in sedentary individuals. (This means those just starting to run are more likely to experience the muscle-building benefits.) Those study authors suggest aerobic exercise as a mechanism to stave off the muscle loss in your diet to help with this process.
Likewise, a 2017 study published in the International Journal of Exercise Science found that running induced muscle growth in the vastus lateralis muscle (one of the quadricep muscles) in 12 recreationally active university students. The participants completed about 25 sessions of high-intensity running (four sets of four minutes of running at 90 to 95 percent of published in the journal, with three minutes of active rest in between) for 10 weeks.
This muscle growth likely stems from the way running loads the body—more specifically, the lower body. “With running, the majority of the muscle work or contraction is eccentric, which is the hardest load on the body,” Joe McConkey, This Training Switch Led Me to Love Summer Running Runner’s World. Eccentric contractions occur when a muscle lengthens under load or tension. For example, during the lowering phase of a squat, the quadriceps (front of thigh) muscles eccentrically contract.
When running, “the act of landing, where you’re absorbing two to four times your body weight, is done eccentrically. That’s the major stimulus for muscle growth during running, particularly for beginners,” McConkey says.
The Limitations of Running on Muscle Building
Recent research Nutrition - Weight Loss maintaining muscle mass, rather than building it. That’s especially true if you stick to a similar routine, without adding intensity.
That said, new runners, compared to those who have been running for a while, are more likely to see the most noticeable changes in muscle mass and strength just by virtue of running more often or for longer for the first time (or the first time in a long time).
Also, even though runners who consistently do steady-state runs won’t build more muscle mass, their muscles can start to look more defined as body composition changes due to increasing mileage, adds McConkey.
If you’ve been running a long time, you’ve also probably already built strength in the slow-twitch muscle fibers that primarily power your long distance running, Janet Hamilton, C.S.C.S., owner of Running Strong, tells Runner’s World.
All runners can develop more strength—in terms of power and muscle ability—and likely more muscle by tapping into their fast-twitch muscle fibers, which have less endurance than slow-twitch fibers but exert more force. “These don’t really get called upon until either a) there’s an activity that requires more strength than slow-twitch fibers can muster or b) the slow-twitch fibers are fatigued and you keep going,” says Hamilton.
To recruit more of those fast-twitch fibers, you need to do something that requires greater power output. Think about the massive leg muscles of a sprinter: “Any high-powered, short bout of exercise—so long as it is progressive in nature (i.e. harder, faster, higher than what you have already adapted to)—will increase the size of fast-twitch fibers, and thus increase muscle mass,” says McConkey.
In summary, to promote muscle growth, you need a bigger challenge on your muscles and a variety of challenges, otherwise running will offer more maintenance than progression.
How to Increase the Muscle-Building Benefits of Running
To support your muscle-building efforts, consider the general exercise recommendations for each week: at least three cardio workouts, two strength workouts, and at least one flexibility workout. Incorporating these all into your routine will not only support your muscles, but make you a more well-rounded athlete.
The Run/Walk Method weight training. Strength workouts create micro-tears in your muscles that, during recovery, build back bigger and stronger. You also need enough protein in your diet to help with this process.
When it comes to running, though, an easy way to build fast-twitch fibers and muscle mass is through hill workouts. “Running up a hill requires more muscle power than running on level ground,” says Hamilton. You may not be lifting a weight, but you’re carrying your own weight up an incline against the force of gravity—its own kind of resistance training.
Speed workouts will also engage fast-twitch muscle fibers. “If you’ve been doing nothing but easy effort, marathon-pace runs, incorporating short to moderate intervals at a faster, 5K pace is going to require you to exert more force every time your foot hits the ground,” says Hamilton. “And that’s how you speed up—you generate a greater push-off.”
To build more muscle on your runs, check out these workouts below. The mileage, effort, and total distance will depend on your running fitness, but each workout can be scaled up or down to meet you where you are in your training.
Beginner Hill Workout
- Warm up for at least 1 mile at easy effort (or 1/3 of the day’s total planned distance).
- Find a gradual hill that takes about 30 to 60 seconds to run up at an easy effort.
- Run up the hill at the same effort as you would on level ground (you will slow down a bit).
- Run down the hill at the same effort as you would on level ground (you will speed up a bit).
- Repeat 1-4 times (depending on fitness level). Focus on cadence, rather than pace, for best results.
- Cool down for at least 1 mile at easy effort.
Intermediate Speed Workout
- Warm up for at least 1 mile at easy effort.
- Run 400 meters at 5K pace (a hard effort but not a sprint).
- Run 200 meters at recovery pace.
- Repeat 2 to 4 times if you run less than 20 miles per week. Repeat 6 times if you run at 20+ miles a week, or 8 times if you run 30+ miles per week. The goal is sustaining a hard pace, so if you need to shorten the distance to maintain that pace, go for it.
- Cool down for at least 1 mile at easy effort.
John Vasudevan, M.D. is an associate professor at the University of Pennsylvania. He is board-certified in Physical Medicine & Rehabilitation and Sports Medicine. He is a Team Physician for UPenn Athletics and medical director of the Broad Street Run and Philadelphia Distance Run, and previously for the Rock 'n' Roll Half-Marathon and Tri-Rock Triathlon in Philadelphia. He is a director of the running and endurance Sports Medicine Program at Penn Medicine. Dr. Vasudevan provides non-operative management of musculoskeletal conditions affecting athletes and active individuals of all levels, and combines injury rehabilitation with injury prevention. He utilizes a variety of ultrasound-guided procedures and regenerative approaches such as platelet-rich plasma and percutaneous ultrasonic tenotomy. He sees patients at the Penn Medicine and the Philadelphia Veterans Administration hospital. Dr. Vasudevan attended medical school at the University of Wisconsin School of Medicine and Public Health in Madison. After his Transitional Year in Tucson, Arizona, he went to residency in PM&R at Thomas Jefferson University in Philadelphia and onwards to Stanford University for his fellowship in Sports Medicine. He has been in practice at the University of Pennsylvania since 2012.
