Mindfulness does not mean pushing oneself toward something or hanging on to something. It means allowing oneself to be there in the very moment of what is happening in the living process - and then letting go.
For the warrior, every moment is a challenge to be genuine, and each challenge is delightful. When you let go properly, you can relax and enjoy the challenge.
In Tibetan, authentic presence is wangthang, which literally means, 'field of power'... The cause or the virtue that brings about authentic presence is emptying out and letting go. You have to be without clinging.