The key is to look at the type of running. Generally, fitness running mainly relies on the feet to follow the ground, and then transitions to the forefoot off the ground. This kind of running has little burden on calf muscles, mainly thigh and hip muscles. If it is a fast competitive race, such as 100 meters, long jump and other events, the forefoot is mainly on the ground, and the heel is not on the ground. This kind of running method has the greatest burden on calf muscles, and it is easy to cause achilles tendon strain if you practice too much.