Quote Waysun Liao, Tai Chi Classics: "T'ai Chi masters traditionally taught their students to use meditative practice to develop ch'i awareness. Such a training program would require a longer period of time to complete than other methods; in this way the master would have time to observe the student's attitude and personality and determine whether or not to continue the program of instruction. Otherwise, the student could develop ch'i awareness for unacceptable reasons, such as poor attitude, ego, or wanting to be stronger than others. If such motivations emerged, the teacher would discontinue instruction without giving the student such key techniques as condensing breathing, which is the main process used to convert ch'i into internal power."   What many people don't understand is that there are training methods for outdoor-students and training methods for indoor-students. The difference is that indoor methods are much more powerful for cultivation than outdoor methods. In legit Tai Chi for example, to every Tai Chi moving meditation exercise (outdoor method), there is a Nei Kung exercise (indoor method), both usually sharing the same name. The Tai Chi moving meditation exercise is about 80% physical and 20% mental, the corresponding Nei Kung exercise is about 20% physical and 80% mental, which explains why the corresponding Nei Kung exercises are so much more effective. Only those considered worthy ("indoor students") are taught the Nei Kung exercises, therefore allowing them a level of cultivation impossible to achieve for those who only use Tai Chi moving meditation exercises ("outdoor students").   I assume that this is the case in every legit internal martial art system.