You have studied the techniques and proper nutrition which go into building the body and maintaining energy. You know how to stretch, prepare for lifting, how to care for aching muscles, and what food lends itself to improved performance. At the higher levels, you are experienced in effective training techniques to build endurance in a student.
This skill may help deal with combat penalties related to exhaustion and pain. Like any skill, every 3 or 4 levels may cancel one penalty with GM's discretion.