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Physical fitness has five important components:

Aerobic Endurance/Cardio-respiratory Fitness

Aerobic endurance pertains to the body's ability to use oxygen. It is the combination of the respiratory system (lungs) and the circulatory system (cardio-heart and blood vessels) that provides the working muscles with enough oxygen to continue exercise for extended periods of time. Aerobic endurance allows you to last longer when participating in activities such as running, walking, climbing stairs, riding a bike or swimming. The more aerobic endurance people have, the easier it is for them to participate in physical activity.

When exercising for aerobic endurance, you should never be breathless or exercise to the point that you cannot talk while engaging in the activity. Aerobic exercising includes activities that use the large muscle groups such as the legs and arms. Aerobic activities include: brisk walking, jogging, bicycling, swimming, aerobic dance, racket sports and rowing.

Muscular Strength and Endurance

Muscular strength is the ability to exert a force against some type of resistance. Lifting a weight, picking up books from a desk and standing up from a chair are all examples of muscular strength. Strengthening the muscles allows people to lift heavier weights, pick up more books from a desk or stand up from a chair with greater ease.

Muscular endurance refers to the ability to repeat muscle exertions. Sit-ups, push-ups, moving many boxes of books and squatting repeatedly are examples of muscular endurance activities. As muscular endurance increases, the ability to repeat muscle exertions also increases.


Flexibility is the ability to move through the full range of motion allowed by a joint. Flexibility depends on many factors, including age, gender, body fat/muscle mass ratio and exercises done to enhance flexibility. Females tend to be more flexible than males because of their body composition (body fat to muscle mass ratio). The older people get, the less flexible they become, because joint mobility decreases. The more a joint is used, the more flexible it will become.

Increasing flexibility is most effectively achieved through stretching. Stretching lengthens the muscles. The most important areas in which to maintain flexibility are the neck, shoulders, hamstring muscles (back of upper leg), chest and hips. It is important to never stretch a cold muscle. Always warm up before stretching with some light activity. In addition, never bounce when stretching, and don't stretch to the point of pain.

Body Composition

Body composition refers to percentage of body fat found in the body. The number of pounds a person weighs is not as important as body fat percentage. Women should fall within the range of 19 to 26 percent body fat, and men should fall within the range of 15 to 19 percent body fat. Women typically have a greater percentage of body fat, due to the extra energy demands placed upon their bodies during pregnancy and breast feeding-this is a natural occurrence. Several different tests can evaluate body fat percentage. Qualified health care professionals should perform these tests. Body fat percentage can be altered through a sound exercise program and healthy eating habits (those that follow the dietary guidelines).