In fact, I don't think you need to worry, because what you think of the thigh thickening after running is just an illusion. Unless you are a professional athlete, and after a long period of intense training, it is possible to make your calf muscles strong.

If you are just an ordinary amateur runner, it is impossible to make the calf and thigh muscles strong just by running a small step every day. The reason why I feel the muscles of my calf and thigh thicken is because I often don't do some proper warm-up exercises before running. Then you don't pay attention to your running posture, especially the landing action. If you run with your toes on the ground for a long time, your leg muscles will be damaged during a long stretch.

So your calves and thighs will be injured by muscle damage. Secondly, there will be some nervous feelings, and then you will feel that your calves and thighs are getting thicker. In fact, this is just an illusion, because human muscles are actually born. Even if you want to thicken your muscles through later exercises, there are many ways, but it is basically impossible to shape your calves and calves only through these aerobic exercises.

So I don't think you need to worry too much about the calf muscles getting thicker because of running. You just need to warm up before running, and then learn how to run more to make your legs easier, instead of focusing too much on the satiety caused by another kind of pain after running, feeling that the calf muscles will thicken.