The five components of fitness include cardio endurance, muscular strength, muscular endurance, flexibility, and body composition. Cardio endurance is your ability to perform an aerobic exercise, such as walking or running, for a certain length of time. Muscular strength measures your ability to move objects, such as dumbbells, by exerting force. Muscular endurance is how well you can sustain that movement before becoming fatigued. Flexibility refers to your ability to move your joints through a range of motion. Body composition describes the ratio of fat and muscle in your physique.