When running has become a habit, it is not very helpful to lose fat. You can change different aerobic exercise methods, such as HIIT, cycling, swimming, climbing stairs and so on. Don't let your body be in an adaptive state of running. And the calf muscles you mentioned, I think it must be that you didn't stretch the calf muscles scientifically before and after running. If you stretch, it's just the stretched gastrocnemius (we usually say calf). Stretching gastrocnemius after running will only make your gastrocnemius stronger. It is the thinner and longer legs that stretch the soleus muscle. As for how to stretch, there are a lot of tutorials online, so I won't say much here. Also, the exercise time of 50-60min is too long, and 45min is the most suitable.