Stamina is a measure of chemical energy and fatigue. It's not the same as physical energy as Naruto defines it. That is my point. At least read my comment thoroughly before replying.
You are not reading anything I type. What's the point. Naruto's physical energy isn't the energy that we need for biological purposes. Naruto's physical energy is shown to gather as a sphere in the center of the body. There is no scientific doc that you can provide that proves that our body's chemical reactions function that way.
Now you changed your argument. I already know you will never admit you lost but I guess that is hard in itself.
Physical energy doesn't exist in real life scientifically speaking. Our bodies don't create ki like energy in them.
stamina is literally considered a form of physical energy, specifically related to the body’s ability to sustain prolonged physical or mental effort.
1.
Physical Stamina: This refers to the body’s capacity to perform physical activities It literally involves uthe efficiency of muscles, cardiovascular health, and literally overall physical conditioning.
2.
Mental Stamina: on the other hand involves the ability to maintain focus and mental endurance basically mental concentration or effort.
Now what is chakra formed by humans or shinobi?
Chakra= both mental and physical energyare combined to create an energy source. Basically manipulating the energy produced is used for ninjutsu, genjustu or taijustsu.
Yes even guy uses chakra though he cant manipulate it to create ninjutsu properly, however he can use it to empower his physicals (speed) to bend space.
If I tell you jump, and you do I promise you just used the concept of chakra that name does not matter. You used energy both physical and mental. Basically to not use both at all is to be dead.
there is something called chakra reserves to store up your energies to use later. That chakra reserves for Kurama is immeasurable(not infinite but a lot). This is what is causing the tears because that right there is a mass of chakra.