The Shaolin monastery was first associated with Bodhidharma around the beginning of the 8th century by the Northern School's lineage story. But connecting Bodhidharma with martial arts happened almost a thousand years later in 1642 (see Faure: Chan Buddhism in Ritual Context, p. 91 and McRae: Seeing Through Zen, p. 26).
For me to see connection with body cultivation and the path of liberation would require instructions given in the sutras and the writings of the masters. So far I have not encountered any sutra or manual in Mahayana Buddhism that teaches such techniques, unlike in Vajrayana.
No one knows anything for certain about Bodhidharma, and the Zen lineages are completely apocryphal. More importantly, and I am sorry to be the one to break this to you, but nothing truely secret or precious has EVER been written down in texts.