Martial arts are beneficial for stress relief in part because they emphasize breathing technique. Not only are these techniques handy in the studio, but you can use them in meditation as well.
To practice this meditative breathing, all you have to do is close your eyes and relax, while keeping your posture straight. Just take deep breaths while focusing on your breath instead of whatever may have happened during the day that’s weighing on your mind. Inhale through your nose, and exhale through your mouth for as long as it takes for your mind to calm down.