This document discusses the importance of warming up before exercise or sports. It notes that a warm-up increases heart rate and flexibility, relaxing muscles and reducing injury risk. A proper warm-up includes joint mobility exercises, activation exercises involving the whole body, and light sport-specific drills. Joint mobility involves moving ankles, knees, hips, shoulders, elbows, wrists and neck. Activation includes running, skipping, leg raises and sprints. A sample warm-up game is described where players try to tag each other with a basketball.