Running does build muscle as long as you are constantly challenging yourself. Running primarily builds muscles in the lower body like your glutes, quads, and hamstrings. To build muscle while running, be sure to fuel yourself with carbohydrates and proteins both before and after your workout.
Also, does running bulk up your legs?
Running uses your glutes, quadriceps, hamstring and calves constantly, meaning that your leg muscles are working and this will cause them to develop and get bigger in size. Any form of exercise that engages your muscles will cause them to grow in size.
And for runners who don’t have time to hop on a treadmill or to head outside for a run, simply running in place while activating your core muscles can be effective for strengthening all of your postural muscles, including the abs, according to studies.
Considering this, what muscles get toned from running?
Running targets mainly your legs and butt. The muscles which are used to power you through your run are quadriceps, hamstrings, calves and glutes. Regular running will definitely get you a toned, fit body including a firm butt.