Teal'c is training Krista James
Lok'nel is a martial art practiced by Jaffa, in which Teal'c is very well-versed. It appears to focus on close quarters, unarmed combat. In 2004, Teal'c trained Krista James in it as she asked, so that she could defend herself. She later used what she learned to kill Douglas Robert McNair in self-defense. (SG1: "Affinity")