Does running build muscle? Probably one of the most asked questions and sought after answers. This question can yield tons of results and also more questions in return. You can ask anyone if running builds muscle and they are most likely going to tell you “it depends.” Yes, annoying I know but true. It really does depend. It depends upon whether or not you are trying to gain muscle size/mass, maintain muscle, or lose weight. Are we talking about long distance running, some running for cardio, sprinting, ultra marathon training? See, more questions.
First, lets picture an Olympic sprinter and a distance runner. Put these two images side by side in your mind. What are you seeing? You are probably noticing that the sprinter has well defined lower extremity muscles. Their hamstrings are easily identifiable as are their calves and quads. They probably also have a “thicker” look to their legs/body as well. Now lets focus in on the distance runner. You see defined muscles but they appear smaller in size (not as thick). In this mental comparison it is easy to spot that the distance runner lacks muscle size. But then again you are probably not an Olympian running 80 plus miles a week (if you are kudos).
So how do you get the best of both worlds? First, figure out what your goals are and prioritize. Now, what if you are the person who wants to build the glutes, quads and hamstrings but also run a half or full marathon? The key here is balance. You need to find a combination of running, nutrition and weight lifting that works with you and your schedule. Tough yes, impossible no.
Before we dive into all that fun stuff about balance lets look at some research. One study speaks of there being two distinct adaptive responses that can be induced in muscle with exercise, hypertrophy (enlargement) of the muscle cells (seen in weight lifters) and an increase in the capacity of muscle for aerobic metabolism (seen in distance runners). These happen independently of each other. So the hypertrophied muscles of a weight lifter does not appear to have an increased respiratory capacity in muscle whereas the muscles in a distance runner has a large respiratory capacity but the muscles are not hypertrophied and show no signs of increased strength.
Another study looks at female runners who were randomly assigned to an endurance and strength training program and an endurance only program. After 10 weeks it was found that strength with endurance training improves the overall form of the runner but has little to no impact on body composition.
Lets take a quick peak at sprinting and building muscle size. Though speed work may not be the primary method for muscle growth, it does help to “speed up” the hypertrophy process. How? Speed training is one of the best methods for losing fat and recruiting more muscles to kick off. Studies have shown that the landing impact during strides in sprinting can exceed 3x your bodyweight, which can help promote tissue growth. To sum it up without getting to technical, sprinting can help BUILD muscle size. Most weightlifters will incorporate some form of speed work into their routine because it can really help to build the glutes, hamstrings and even your abs!!
So back to distance running. You might even ask how come when I step on the scale I weight more than I did when I wasn’t running. It must be because I am gaining muscle right? Well for starters, when you increase your training your body begins to store more water than normal to help repair damaged muscle fibers. Or you may be drinking more water to stay hydrated. Water weight can be a bitch. You could also be overeating. When you start running your body is shocked you are burning more calories than normal so you will become hungrier more often. So when you are hungry you feed yourself! Sometimes we can get a bit carried away with this. Just because you are exercising does not mean you get to over indulge in food. Bummer. Your body will burn fat when you run 3-4x a week and increase mileage helping to carve out those leg muscles. A study has shown that distance running paired with heavy resistance weight training increased strength but had no overall changes to girth. Another thing to remember is if you are running and doing cross training sessions you need to up your caloric intake. Now, I don’t mean stuff your face with donuts. I mean eat more protein, complex carbs and vegetables. Play around on myfitnesspal or another comparable website to see how many calories you need to help maintain, lose, or gain mass. As you increase mileage you are also increasing the difficulty to build muscle mass and nutrition will begin to play a more major role.
So, in summary, first, You WILL NOT gain any size if you do not intake more calories. Whether you want to sprint, run long distances, or just do short runs for cardio. If you do not increase your caloric intake you will not see any gains. Plain and simple. Second, if you are looking to put on some size, distance running should not be your first choice. The more miles you start packing in during the week the more difficult it will be to add size to your legs/glutes. Shorter runs not exceeding 20-25 miles a week paired with an increase in calorie intake and weight training will help reduce body fat and increase muscle size. If you are looking to just get any kind of cardio in, sprinting would be your best option especially if putting on size is your main focus (it’s your holy grail to decreasing fat and increasing muscle mass). Again, training for that half marathon or marathon may help to decrease your body fat also and give you definition in your legs, but it will not help increase the girth (you will probably not put on size). Even if you pair it with weight training and tons of calories, you may notice your legs looking more “cut up” but the size will more or less stay the same. Remember, it is all about balance. Plan out your workouts each week and your meals accordingly!