The five components of physical fitness are cardiovascular endurance, muscle strength, muscle endurance, flexibility and body composition. Schools and gyms use the components to measure the level of a person's fitness.
Cardiovascular endurance is associated with the way the heart and lungs work together to provide the body with oxygen. Aerobic exercise, such as swimming or jogging, can help improve a person's cardiovascular endurance.
Muscle strength has to do with the amount of force a muscle can apply in an endeavor. A person can improve muscle strength by engaging in regular strength training exercises, such as weightlifting.
Muscle endurance measures how much continuous action a muscle can perform without exhaustion. Cycling machines, step machines, inclined treadmills, sit-ups and push-ups can test muscle endurance and help improve this component.
Flexibility measures the range of motion a joint has. Stretching the muscles can test how flexible a person is and increase that level.
Body composition is the percentage of fat, bone, water and muscle a person's body contains. The pinch test is performed with a special instrument that measures the fat around a person's waist. Regular exercise and a healthy diet can lessen body fat.
A doctor or personal fitness trainer can help develop a regimen to strengthen a person's physical fitness components.