This document discusses warm ups and cool downs for exercise. It defines a warm up as low-intensity movements that mimic the intended activity in order to prepare muscles and increase blood flow. A warm up should include a general activity to raise heart rate, sport-specific movements, and dynamic stretching. The benefits of warming up are injury prevention, increased oxygen delivery, and prepared muscles. A cool down after exercise is also important to gradually lower heart rate and stretch muscles to avoid injury and remove waste products.