Physical fitness refers to the ability to perform daily tasks with alertness and vigor. There are two main components of physical fitness - health-related fitness and skills-related fitness. Health-related fitness includes cardio-respiratory endurance, muscular strength, flexibility, muscular endurance, and body composition. Skills-related fitness consists of coordination, speed, balance, power, agility, and reaction time. The document discusses these components of physical fitness and provides examples of tests to measure aspects of health-related fitness like BMI, flexibility, cardiovascular endurance, and strength.