You don't need to be interested in spirituality at all to work with physical or mental chi. I've yet to meet a sensei (master/teacher of martial arts like Karate) who qualifies for sainthood. Physical and mental life-force energy or chi is the driving force behind accomplishments like chopping a cement block in half with one blow from a bare hand.

Martial artists generate a surcharge of physical life-force energy first (through exercise), then direct that energy toward their goal using simply will and intent. All that's required to chop a cement block in half with your bare hand is a reasonably healthy physique and a highly trained, disciplined and focused mind. Plus the willingness to work with an invisible force like life-force energy, of course.

Ker-ist. I just can't stand it.