Most martial arts at some point get deep into the idea of increasing power. The problem with that is most martial artists delude themselves because they do not have an adrenalized high-risk-of-injury place to test out their practice. When I've worked with people who had an opportunity to test their power four nights a week breaking down doors, they only used the amount of force necessary and it is usually less than a martial artist who is only imagining the usage. Even great martial arts, who perfectly understand how power works, tend to over-power.
That is just a prelude to a misunderstood metaphor which is very common in Chinese martial arts circles. The metaphor is that of a bow shooting an arrow.
The way most people understand it, you use force to pull the bow back, which momentarily stores that energy, and then it is suddenly released, striking your opponent. It is sometimes called fajin especially when it is done with the hand already touching the opponent's body.
Kuo Lien-ying, my first teacher's teacher, said that there are five bows in the body, 2 arms, 2 legs, and the spine. Most people focus on storing energy in the spine. My teacher Kumar Frantzis had a whole qigong system built around opening and closing (shrinking and expanding) every part of the spine so that it could store and release the maximum amount of energy. It is good training, but not for that purpose. He had another qigong system for the kua (hip area), with the same problem--good training, wrong purpose.
The problem here is a misunderstanding of the metaphor. The Chinese word for drawing a bow is yin 引, as in Daoyin 導引. It doesn't mean to draw or pull, it means to empty or hollow out. The Chinese word conceptualizes the power of a bow as being generated by the empty space created when a bow is drawn. Not by the pull. Not by the bend, not by the tension, and not by storing energy in the bent bow or the string.
The correct understanding of the metaphor is that your body draws inward from all directions to create a larger empty space in and around the torso. It then relaxes out in all directions without letting go of that draw. It is a bit like turning on a motor in the simple sense that once it is on, it stays on, until you decide to turn it off.
The metaphor goes further. Once you have pulled a bow, you can hold it open while you track a target. If you are a really good shot, you will be very calm and smooth, so smooth that you can release the arrow in between heart beats. Thus you pause with potential-energy (in the precise physics sense of the word). This pause, is called shi 勢 in Chinese, and Roger T. Ames wrote his dissertation on it years ago.
For my teacher George Xu, this shi 勢 is key to power and power-deception. He likens it to fighting with a drawn bow. It is like a constant threat that causes people to either cower or freeze. You can shoot them, but if you use shi 勢 effectively you won't have to.