Right. The Eight Inner Gates are a series of limiters the body has that naturally prevent one from accessing all of your chakra at once. To prevent too much strain on one individual gate, there are 8 of them throughout the body. These gates are located in various places, each with a different name and location. One may ask about the Gates and wonder what would the purpose of these gates. And the reason of that is simple: without these restraints, the body would consume and utilize too much chakra and life energy, shortening the life span. I associate EIG with Yang as it is a very physical ability, and is closely related to the life of a Shinobi. While not directly stated how, we know that these gates activation is learned through extensive physical training and immense force being channeled to these gates. As you said, essentially utilizing our physical energy into them to do this. But merely channeling the the chakra will not be enough. That is the point of the heavy training of course. By undergoing training, you build your physical energy so that you have a high level of energy. As I believe, each gate requires a higher amount of physical energy to be channeled into it. And as such, you must build a higher tolerance to pain and become more accustomed to this training.
To begin, we start with the first gate. The Kaimon, located in the left side of the brain. This gate removes the limits on the chakra in the brain that naturally prevents us from using all of our strength. By removing this restraint, you start on the path to using your full power. Now, as you are meditating already, your spiritual energy is at a peak, whereas your physical energy is more dormant here. The way I was trained, we forcibly injected chakra into you, centered around that gate to allow you to access that first gate. I will do that now, and then later, have you try to recreate that feeling. Ready?
By the time Quiver finishes his words, he had already channeled a large amount of chakra to his right finger and pokes Talos on the forehead above the left eye, forcibly opening the gate.
So how does that feel? Run a few laps for me before we proceed.