Girls constantly complain about wanting to lose weight, and well-meaning people recommend running. The girls immediately retort, "I don't want my calves to get thick from running!!!" Does running make your calves bulky?
Fitness experts offer this advice: "Running is an aerobic exercise, so it won't bulk up your calf muscles," and ""Fast running might, but slow endurance running won't—because sprinting is explosive anaerobic exercise, while slow running is low-intensity aerobic exercise." "Running won't make your legs thick; it just firms the muscles. Stretching will relax them and prevent bulkiness." "You absolutely must stretch—otherwise they'll get thicker!"But their theories are correct only under one premise: "The runner employs ideal, correct running form."
For those unskilled at running, it can indeed thicken calf muscles. Of course, if there's significant calf fat, they'll still appear noticeably slimmer because muscle gain is minimal. Interestingly, skilled runners don't experience this effect.
Why?Before explaining, let me tell you about the guy with the thickest calves I've ever seen. Two years ago while training Brazilian Jiu-Jitsu in Shanghai, we faced off against Wan Hongchen—the fighter who defeated the Japanese competitor in just seconds during the second season of "Rui Wu"—and another individual, a national champion in Chinese wrestling. The latter is the person with the thickest calves I've ever witnessed. The circumference around his Achilles tendon alone measured over 30 centimeters, with the widest part exceeding 40 centimeters.The reason lies in judo and wrestling training. To constantly maintain balance against repeated disruptions, calf muscles must perform extensive support work across various angles. Consequently, their development is inevitable. Like forearm muscles, calf muscles are composed of fine, dense fibers. This endurance-based movement is particularly conducive to their growth.
Now, back to running. If you get the chance this winter, try this experiment: find a man who excels at running and a woman who doesn't. Have them run fifty meters in a straight line on ground covered with a light dusting of snow. Examine their footprints. You'll notice the woman's footprints are more scattered than the man's.This indicates that her center of gravity cannot stay aligned with her body's central axis due to poor core and hip stability. Consequently, she must constantly engage her calf muscles to compensate—meaning her calves are undergoing endurance training!!!
For skilled runners, this issue is either nonexistent or negligible. For those who struggle with running and use treadmills, however, this problem is amplified.
It must be noted, however, that even if running may increase calf muscle mass for those unaccustomed to running, the gain remains modest. For thick calves primarily composed of fat, this increase won't cause noticeable circumference growth.
Even for muscular calves, the rate of increase will eventually slow and plateau once you transition from being unaccustomed to running to becoming proficient.
Conclusion:Running may slightly increase calf muscle mass for those unaccustomed to running. The recommended approach is to prioritize core and relevant joint strength training early on to prevent the calf muscles from compensating for improper posture.