There are no absolute right answers to this question. Instead of giving the one true answer to this, below are several different opinions. (a) Ki doesn't exist. Everything the ki model tries to explain can be explained with body mechanics, biophysics, and psychology. There is no need to postulate some mysterious force. Science can explain it. (b) Ki exists absolutely. Ki is an energy, a living force, a spirit that can be used to increase your strength, throw people around, etc. Subjective experience shows that ki is real. It may either be a bio-kinetic phenomena science doesn't understand yet or the power of the mind in union with the body. (c) Ki may or may not "really" exist. It is a useful model. The ki model allows you to visualize how to increase your strength, throw people around, etc.--it doesn't matter if it exists or not. If someone invents a better model (i.e. one that is easier to visualize), then maybe we'll switch to it. Of the styles that stress ki, some work on developing the flow of ki within their bodies. An example of this approach is Taijiquan. Other styles work on letting the ki of the universe flow through them.

Chi is an internal experience of quiet,and flexible (flow) movement. It is often represented by Circus Acts . I am sure you have seen strong-men breaking ice blocks,or people bending iron bars with their neck.These acts are amazing . They have nothing to do with chi. Some people have Chi naturally, others develope it with practice . My observation is that Chi is poorly understood ,because most people including martial artists ,simply dont have much . Most of the methods of developing Chi are commerial ventures more designed to generate revenue (apologies to the real schools out there). It takes years of practice (for most) to actually experience it. Some people just have it ,and its not a function of physical conditioning. Some people without training experience the Chi by nature. Its a type of grace,flow,connection. Some animals (deer in motion) are loaded with Chi. You look at them and say Whow... thats the Chi Your house cat is likely to have more Chi than the usual martial artist (some exceptions) . Martial arts are great!! I love martial Arts! The continious flowing motions in the arts may improve the practioners Chi...meditation may improve the Chi..or sometimes nothing improves the Chi ...sorry. Many Chi experts just dont have much Chi..sorry..some do. I am just guessing here, but I think its a natural thing that we ,as people may have lost (or reduced ) over time. Hey, but what do I know?

Qi in English is often spelled as chi. The Japanese form is ki. Qi is a fundamental concept of everyday Asian culture or philosophy, most often defined as "air" or "breath" and, by extension, "life force" or simply put, just "energy" that is part of everything that exists. In regards to the Martial Arts and physical health: The overall effectiveness of qi is directly related to posture, (whether moving or stationary), breathing techniques, and mental focus. Qi is the conceptual layer of understanding that practitioners place upon the actual physiological activity relating to the movement of the various types of biological or chemical energy within the body. Essentially, using mental focus, relaxation, and posture, practitioners create a link between their mind, and that of their body, through various training methods - in order to become more sensitive to the internal processes taking place throughout their own physical being. Acupuncture and acupressure, both work by distracting from or adding to, the pain stimuli passed through to the nervous system. These procedures help stimulate the manufacture of endorphins, which are the body's own opiates. There are many low level electrical processes occurring. Use of these pressure points have been shown as being able to affect the parts of the central nervous system related to sensation and involuntary body functions, such as immune reactions and processes that regulate a person's blood pressure, blood flow, and body temperature. Western science is working toward an actual understanding of the qi or energies involved. Everyday activities such as walking, or stair climbing, along with swimming, aerobics, and Martial Arts may also aid in the flow of these various types of bioelectrical energies through the pathways leading to and from the Central Nervous System, and along the path of the many pressure points within the body. Based upon science's own inability to measure the many different types of energy involved, qi will inevitably become more categorized over the next few decades, as we get more precise instruments to measure those types of bioelectrical changes. During this time, there will be a more scientific based understanding of qi, rather than many of the unfounded mystical or religious reasons we see in place today.

Here's a good video of the Chinese understanding of chi thanks to youtube. These Shaolin guys are NUTS!!!

There is a person who express 'Ki' is real and absolutely exsists. He can make us feel "Ki" that is really amazing experience. His name is Mr.Kenji Ushiro. He is Grand master of Japanese Traditional karate. he is 58 years old and not big ,not musle guy but he can throw big musle guy away and stop big guy rushing to him. you can see his video at http://www.aikinews.com/page.php?id=7 ( top video clip and second top video clip) or http://budo.blog81.fc2.com/blog-entry-44.html