* soleus muscle: soleus muscle is the foundation of the back of the calf. If you want to use the calf to exert force, you need to use soleus muscle, which is the most difficult muscle to heal. It is the most difficult to recover after using soleus muscle.
* Medial rectus muscle: The medial rectus muscle is one of the extraocular muscles. Its importance lies in that if it is lost, it is the most difficult to retrieve, and it will retract into the eyeball and cannot be taken out.
In short, there are two kinds of sayings that it is most difficult to get back after muscle loss, one is soleus muscle and the other is medial rectus muscle.