by Trudy Despain
(last updated August 23, 2013)
Too often physical fitness is judged by a person's waistline and scale weight. True physical fitness can't be judged based on outward appearances. The definition of physical fitness has evolved over the years. Today it is generally accepted that physical fitness is determined based on "a set of attributes that people have or achieve relating to their ability to perform physical activity." (U.S. Dept. of Health and Human Services, 1996). Those attributes are body composition, cardiovascular fitness, flexibility, muscular endurance and muscle strength.
Body composition is the only attribute that is not related to physical performance so it's inclusion as an indicator of physical fitness is scrutinized. However, body composition is related to the relative amounts of muscle, fat, bone, and other vital boy parts. (From Surgeon General's Report on Physical Activity and Health, USDHHS, 1996). Body composition is best measured in a clinic using Dual Energy X-Ray Absortiometry or DEXA. DEXA requires very expensive machinery and is really only used in clinical settings. For home use, the best method to determine body composition by using a scale that employs bioelectrical impedance analysis or BIA. This type of scale sends a small electrical signal through the body. Lean muscle mass contains more water than body fat and therefore conducts electricity more quickly than fat tissue. The BIA scale measures the amount of time required for the electrical signal to travel through the body. Slower travel times indicate higher body fat while faster travel times indicate higher levels of muscle mass. BIA scales are inexpensive and easy to use. While not 100 percent accurate, BIA scales offer a baseline and help determine losses or gains in body fat.
Cardiovascular fitness relates to the ability of the circulatory and respiratory systems to supply oxygen during sustained physical activity. (Surgeon General's Report on Physical Activity and Health, USDHHS, 1996). The best measure of cardiovascular fitness is a VO2 test in a laboratory setting but field tests can be done by individuals that will set a baseline and indicate improvements when tests are administered again weeks later. One way to measure cardiovascular fitness is to perform the step test where you step up and down from a 12-inch step for 3 minutes. The step rate should be 25 to 30 reps (up, up, down, down) per minute. After three minutes, take your heart rate for 15 seconds and multiply it by 4. That will tell you how many times your heart beats in one minute after intensive exercise. The lower the number the better because a lower rate means that your heart is more efficient at delivering oxygen to your working muscles.
Flexibility relates to the range of motion available at a joint. (From Surgeon General's Report on Physical Activity and Health, USDHHS, 1996.) Just as cardiovascular fitness and body composition, there are clinical tests for measuring flexibility but field tests are also reliable. The sit and reach test measures the flexibility of the lower back and hamstrings. The flexibility of these major muscle groups is a good indicator of an individual's ability to perform daily physical requirements with a full range of motion.
Muscular endurance relates to the muscle's ability to continue to perform without fatigue. (Surgeon General's Report on Physical Activity and Health, USDHHS, 1996). Lab tests and field test of muscular endurance are very similar. The tests are performed by measuring the ability of a muscle group to contract repetitively without fatigue. Examples include push-ups, abdominal curls or pull-ups.
Muscle strength relates to the ability of the muscle to exert force. (Surgeon General's Report on Physical Activity and Health, USDHHS, 1996). Test for muscle strength are performed by measuring how much force can be exerted by a muscle or group of muscles during one repetition. Clinical and field tests are performed using resistance machines.
By getting a baseline measurement on the five components of fitness you are able to measure achievements reached during participation in a fitness program. Rather than focusing on weight loss alone, you will be able to see how your efforts are paying off in your body's ability to handle exercise.
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