* מדריך אמנויות לחימה (madrich amunot lichama): This is a general term. "Madrich" (מדריך) means instructor or guide, "amunot" (אומנויות) means arts, and "lichama" (לחימה) means combat or fighting. This is a good all-around option.
* מאמן אמנויות לחימה (ma'amen amunot lichama): This translates to "coach of martial arts." "Ma'amen" (מאמן) implies more of a focus on training and athleticism.
* You could also specify the martial art: For example, מדריך קראטה (madrich karate) for a karate instructor, מאמן ג'ודו (ma'amen judo) for a judo coach, etc. This is the most precise option.
Therefore, מדריך אמנויות לחימה (madrich amunot lichama) or מאמן אמנויות לחימה (ma'amen amunot lichama) are good general choices. If you know the specific martial art, adding that is best.