Components of Physical Fitness

Cardiovascular Fitness 
The ability of the body to perform prolonged, large-muscle, dynamic exercise at moderate to high levels of intensity. This is dependent on the ability of the heart and lungs to deliver oxygen to the working muscles. As fitness levels improve, the body functions more efficiently and the heart can better withstand the strains of everyday stress.

Muscular Strength 
The maximal amount of force a muscle can exert with a single maximal effort. Strong muscles are important for carrying out everyday tasks, such as carrying groceries, doing yard work, and climbing stairs. Muscular strength can help to keep the body in proper alignment, prevent back and leg pain, and provide support for good posture.

Muscular Endurance 
The ability of a muscle or group of muscles to perform repetitive contractions over a period of time. Endurance is a key for everyday life activities and operates with muscular endurance to help maintain good posture and prevent back and leg pain. In addition, endurance can enhance performance during sporting events, as well as help an individual cope with everyday stress.

This refers to the range of motion in a joint or group of joints, correlated with muscle length. This component becomes more important as people age and their joints stiffen up, preventing them from doing everyday tasks. Additionally, good range of motion will allow the body to assume more nautral positions to help maintain good posture. Stretching is therefore an important habit to start, as well as continue, as one ages.

Body Composition 
The relative proportion of fat-free mass to fat mass in the body. Fat-free mass is composed of muscle, bone, organs, and water, whereas fat is the underlying adipose tissue. Excessive fat is a good predictor of health problems because it is associated with cardiovascular disease, high cholesterol, and high blood pressure. Higher proportions of fat-free mass indicate an increase in muscle, and thus an increased ability to adapt to everyday stress. 
The most effective way to participate in a well-rounded program is by following a simple mnemonic device called FITT (Frequency, Intensity, Time, Type). The FITT principle includes how many times a week one should exercise (frequency), how intense the workout should be (intensity), how long the workout is (time), and what modality to use (type of exercise). Modality is dependent primarily on what an individual prefers. This exercise prescription in based on an individual's fitness level when entering the exercise program, and ultimately upon the goals of the individual. For example, an untrained individual who wants to lose weight and likes to walk would be placed on a program of treadmill or outdoor walking (type), for thirty minutes a day (time), three to five times per week (frequency), and of light to moderate intensity (intensity).

A good example of an exercise program would include three stages. The first stage is a warm-up, where one should complete light calisthenics to activate and warm the muscles, immediately followed by stretching, which helps to maintain flexibility. The second stage is the conditioning stage, which consists of cardiovascular work to enhance the function of the heart and lungs and a resistance-training regimen to strengthen and tone major muscle groups, such as the quadriceps, hamstrings, chest, biceps, triceps, back, and abdominals. The final stage consists of a cool down, or reduction in heart rate to resting levels, as well as stretching again, since the greatest modification in flexibility comes from post-exercise stretching.

Maintenance of physical activity is important to maintain a healthy lifestyle. In addition, it is important to follow an exercise regime that will start slow and gradually increase as fitness level and exercise tolerance increases. The key is to complete at least thirty minutes of activity most days of the week in the form of activities that one enjoys, such as walking, jogging, swimming, aerobic dance, biking, skateboarding, or participating in a sport. This will enable an individual to reach the goals of Healthy People 2010, which include improving the quality of life through fitness with the adoption and maintenance of regular exercise and physical activity programs.

 number of deaths related to sedentary living or obesity is approximately a half-million per year. Physical activity may impact quality of life in several ways: it can be used to improve self-image and self-esteem, physical wellness , and health. 
Participation in physical activity can be beneficial for anyone and can be started during any stage of life. One goal of Healthy People 2010, a set of national health objectives established by the U.S. Department of Health and Human Services, is to increase the number of people who participate in daily physical activity. This activity can take many forms, ranging from a regimented exercise program to daily life activities such as house or yard work, walking a pet, or walking around town to complete errands.