This document discusses the purpose and components of a warm up for physical education classes. A warm up consists of exercises that gradually prepare the body for activity by raising the temperature of the muscles and joints. This improves performance and reduces the risk of injury. Specifically, a warm up raises the heart rate to increase blood flow to the muscles, prepares both the body and mind for work, and complements the main part of the physical education session. A warm up generally includes jogging with gentle exercises, mobility and stretching exercises, and strength and speed exercises.