Descripción de Shaolin Yi Jin Jing Muscle & Tendon Changing Classic:

"The basic purpose of Yijinjing is to turn flaccid and frail sinews and tendons into strong and sturdy ones. The movements of Yijinjing are at once vigorous and gentle. Their performance calls for a unity of will and strength, i.e. using ones will to direct the exertion of muscular strength. It is coordinated with breathing. Better muscles and tendons means better health and shape, more resistance, flexibility, endurance, and is obtained as follows: - postures influences the static and nervous structure of the body - stretching muscles and sinews affects organs, joints, meridians and Qi - torsion affects metabolism and Jing production - breathing produce more and better refined Qi - active working gives back balance and strength to body and mind (brain, nervous system and spirit). The Yì Jin Jing (Chinese: ???; Wade-Giles: I Chin Ching; literally "Muscle/Tendon Change Classic") is a qìgong manual most notable as the source of the attribution of Shaolin Kung Fu to Bodhidharma, though this has been doubted by several martial arts historians. Pan Wei was a devoted student and practitioner of traditional Chinese medicine, and his treatise in the form of- a preface reflects his vast knowledge of this subject. It is common knowledge that within the works of Lao-Zu, Chuang Zu, and even Mencius, many references are made to the ancients practicing various forms of breathing exercises. Pan Wei says that he had consulted various medical treatises; however, he did not mention that any had been an Indian work translated into Chinese, nor did he mention that Bodhidharma was the source. Indeed, Pan Wei suggests the exercises are more Chinese and Taoistic in origin than Indian and Buddhistic. Classic Chinese authors tend to insist on the ancient lineage of this practice, but there is no evidence of the connections to Shaolin systems or to a specific routine. Number of exercises tends to change, 18 should be the correct one (according to the 18 Lou Han), but can vary from 10 to 24, to 30" http://en.wikipedia.org/wiki/Y%C3%AC_J%C4%ABn_J%C4%ABng In any case, this is a video of a shaolin monk doing the movements - these guys seem pretty qualified as a primary source.