Also not a biologist - just an enthusiastic layman.
The Soleus muscle (Soleal pump) is partially responsible for helping to return blood from your legs back up to your heart while upright. [1] This is a fairly critical process so it would make sense that it would be able to metabolize multiple energy sources.
The Soleus muscle (Soleal pump) is partially responsible for helping to return blood from your legs back up to your heart while upright. [1] This is a fairly critical process so it would make sense that it would be able to metabolize multiple energy sources.
[1] https://www.physio-pedia.com/Soleus