CHAPTER VII â€“ BODY COMPOSITION
Measuring Body Composition Objectives After reading this chapter, the student should be able to: 1. Discuss the importance of body composition measurements in physical education. 2. Follow the directions for administering the practical body composition measurements. 3. Know which body composition measures are valid and reliable and which ones are not. 4. Understand the problems associated with using anthropometric measures in the assessment of body composition. 5. Differentiate between the terms overweight and over fat and be able to discuss the implications of this difference in the measurement of body composition.
Key Terms Body Composition: Body composition is the technical term used to describe the different components that, when taken together, makes up a person's body weight Lean Tissues: Tissue that is metabolically active, such as muscle, bone, and organs Essential Fat: Fat tissue which supports life, and is extremely important to normal bodily functions Storage Fat: Storage fat is fat that protects internal organs and supplies some energy requirements Non-essential Fat: Non-essential fat is fat that serves no real purpose, and may, in fact, be detrimental to health Body Composition Analysis: Methods of assessing the percent of fat vs. lean mass of an individual Hydrostatic Weighing: A method used for evaluating body composition which involves determining an individualâ€™s residual lung volume, and land weight calculations BOD POD: The Bod Pod composition system uses whole body densitometry to determine body composition (body fat and lean body mass). Body Mass Index (BMI): Body mass index describes relative weight for height. Body Mass Index has recently been used to quantify an individual's obesity level. BMI is derived from a ratio equation of height squared divided by weight. Overweight: Overweight refers to an excess of amount of weight that includes all tissues: bone, muscle, water and fat
Obesity: Obesity refers specifically to body fat. It is defined as having 20% more body fat than normal. Anthro-ElectroLipoGraphy (AELG): A method used for measuring body fat. AELG is the new, state of the art technology, utilizes the algorithmic approach of ElectroLipoGraphy (ELG) coupled with specific anthropometric measurements to further define body fat measurements. Skinfold Thickness: A method used for measuring body fat. With skinfold thickness an estimate of total body fatness is made by measuring subcutaneous fat in various areas of the body. Body fat scales: A method used for measuring body fat. Body fat scales use the Bioelectrical Impedance method to measure your body fat percentage. Dual energy X-ray absorptiometry (DXA, previously DEXA): A method used for measuring body fat. DXA is a single X-ray source is used to determine whole body and regional estimates of lean tissue, bone, mineral and fat. Potassium Ion: A method used for measuring body fat. Potassium Ion is a technique designed to determine the amount of a naturally occurring isotope, potassium. From the amount of total potassium it is possible to estimate the mass of lean tissue. Nuclear Magnetic Resonance (NMR spectroscopy): A method used for measuring body fat. With Nuclear Magnetic Resonance Electromagnetic waves are transmitted through tissues and are absorbed by selected nuclei, which then release energy at a particular frequency (or resonance). Ultrasound: A method used for measuring body fat. With Ultrasound sound waves are transmitted through tissues and the echoes are received and analyzed.
Body Composition For most Americans, physical fitness training entails sitting around eating Doritos, drinking Coca-Cola, and watching Oprah on the tube. If they're real fitness fanatics, they'll watch reruns of Jane Fonda's aerobics. Not surprising, research conducted by the American Medical Association has revealed that 76% of the adult American population is overweight. Amazingly, 31% of overweight people had enough body fat to qualify for clinical obesity, a classification that required an individual to have at least 20% more body fat than normal. Do you want to hear something really scary? Of course you do. According to the National Sporting Goods Association (NSGA), only 2% of the American male population and 6% of the female population is in excellent shape. Even more amazing, 87% of American males are in poor to pitiful shape. And children are getting heavier too, with a higher incidence of obesity now than ever before. These statistics have created somewhat of a critical alert in the medical community since overweight adolescents are very likely to become overweight adults. Again, it’s mathematics and statistics that indicate that America’s obsession with food has become an epidemic. As you get older, it will be more and more difficult to lose and to maintain body weight as your metabolism slows. Why is it so important that you do not become overweight? In part because of the health risks associated with being overweight. Obesity clearly poses substantial risk to health. With respect to health risks that the individual can prevent, obesity is considered to be number two after smoking. Obesity predisposes the individual to medical disorders such as heart disease, kidney disease, diabetes mellitus, high blood pressure, breathing disorders, and greater risk during surgery. It has been scientifically estimated that if everybody were at their optimal weight, there would be twenty-five percent fewer cases of coronary heart disease in the USA. There are psychological as well as medical hazards associated with obesity. Heavy people are discriminated against with respect to employment, promotion, and social acceptance. Also, obese individuals are more likely to have low self-esteem, and experience more anxiety, depression, loneliness, and unhappiness than people who are not overweight. The public has strong biases against fat people. They are often stereotyped as being gluttonous, lazy and sloppy. Many people believe that overweight people lack willpower and do little besides eat. Now here is another news flash! There are almost four billion people in the world and one third of them are suffering from malnutrition. Yet, in the United States we have slightly less than 240 million people and close to a third of them are significantly overweight. From a global standpoint, it would seem that at least a quarter of Americans are eating their share of food and someone else's. Now think about this, we live in the most medically advanced country in the world, yet the success rate of most medical weight loss programs is zero, nada. Of every 100 individuals who go on a weight loss program, only 12 lose weight and only two of those individuals will maintain their weight loss for more than a year. In other words, the success rate of helping someone lose weight is about 2%. That's incredible when you think that the success rate of curing cancer is about 40%. It's even more amazing when you think that the United States spends almost 10 times more money on weight reduction research than it does on cancer research, and that's not counting the billions of dollars that are spent each year on fad diets and gimmicks. If that doesn't freak you out, I don't know what will. In light of the seriousness of obesity…it’s medical, psychological and social implications…and the acknowledgement that exercise is of significant value in the prevention and treatment of obesity, physical educators now generally list weight control as one of the components of physical fitness.
Why Do We Need Body Composition Analysis Total weight on its own is of little importance and far too many people base their diet regimen on what they see on the bathroom scale. Irrespective of total weight, if lean and fat proportions are within established recommended limits then one has a significantly reduced risk of suffering from many health problems associated with being “over fat.” Equally serious, however, is the problem of having too little body fat since adipose tissue is vital for normal organ function. The dramatic increase in anorexia nervosa, bulimia and a “fear of obesity” over the last decade demands an awareness of correct body composition. Consequently, as a physical education instructor who is teaching a unit or a course in weight control, it is essential that you are aware of how to measure and evaluate body composition. Often, diets will result in loss of mostly lean body tissue, and water and weight gain programs may times result in body fat gains. By tracking an individual’s body composition, you can closely monitor what body composition changes are actually occurring. Just knowing how many pounds you have lost is insufficient. The goal of any weight control program and physical fitness program needs to involve adjusting a person’s exercise and dietary habits to achieve his ideal body composition.
Measuring Body Composition Body composition is the technical term used to describe the different components that, when taken collectively, makes up a person's body weight. Understand that body composition and body weight are two entirely different characteristics, which are not transposable. In other words, they can’t be used interchangeable…they are not the same thing. To understand the difference between these two components you need to have a basic knowledge of anatomy and physiology. I am sure you realize that the human body is composed of a variety of different types of tissue. There is lean tissue which is metabolically active such as muscle, bone, and organs, and there is fat tissue such as subcutaneous and adipose which is not metabolically active. Since scientists, like educators, love to classify things, they have divided adipose tissue into three different categories: 1. Essential fat supports life and is extremely important to normal bodily function. 2. Storage fat protects internal organs and supplies some energy requirements. 3. Non-essential fat serves no real purpose, and may, in fact, be detrimental to health. Now, here is one of those news flashes you love so much…you cannot distinguish between which type of fat you have simply by stepping on a scale. A scale simply takes the sum of everything…your fat, muscle, water, hair, and anything else you have inside your little tummy…and gives an absolute weight measurement. Scales can't determine the lean muscle to fat ratio of your weight. This tells us that scales and weight and height charts are not a good indication of a person's ideal body weight for optimal health, and they certainly are not valid measures for assessing an individual’s ideal body weight. Therefore in order to determine an accurate measure of an individual’s body composition, physiologists have developed several different valid methods for assessing the ratio of fat to lean muscle mass in an individual. These methods are referred to as Body Composition Analysis. Body composition measurement is an important part of the initial assessment procedure for ascertaining an individual’s fitness level. For example, excessive body fat is generally an indication of poor physical fitness and is associated with cardiovascular disease, cancer, and other maladies. Body composition assessment can also be an important source of motivation for individuals, as it demonstrates both
positive and negative changes in overall fitness levels. We will talk about these methods in depth in a few minutes, but first we need answer a few important questions.
Questions of Significance What should your body fat percent be? Actually, body fat percent varies considerably for men and women, for age and ethnicity, for those involved in different sports activities, and even for individuals in different geographic locations. However, there are some standards. The minimum percent body fat that is considered safe and acceptable for good health is 5% for males and 12% for females. Don’t worry you are probably not even close to the minimum. Less than one percent of American’s have that little body fat. The normal adult body fat is closer to 15% to 18% for men and 22% to 25% for women. Hopefully your body fat is close to that, but as indicated most American’s seem to be doing their training at the International House of Pancakes. On a more positive note, athletes typically find themselves at the low end of aforementioned scale. Optimal levels of body fat are much lower for those striving for high level performance. Ranges for professional athletes are quite a bit lower than for the average, healthy individual. Much of this difference can be attributed to the increased lean muscle mass of competitive athletes. Interestingly, while levels of body fat seem to be related to performance, body composition alone has never been a great predictor of sports performance. Several studies have suggested that percent body fat is inversely related to maximal aerobic capacity and to distance running performance. Lean muscle mass seems to be positively related to performance in sports where the ability to generate maximal force is required. The body fat percents for elite athletes vary largely by sport. Clearly, the association between low body fat and improved performance is not precise, and there is little evidence of performance benefits when male athletes drop under 8% and women drop under 14% body fat. Swimmers, also, throw a monkey wrench into this generally accepted notion of endurance athletes having lower body fat levels. “Swimmer's body fat mystery,” as it is now known, grew out of the recognition that competition level swimmers have a higher body fat than most other athletes.
How Low Is Too Low? Athletes have been known to take the concept of "low body fat in the name of improved performance" to extremely heights. While the average body fat percent in the United States and Europe is increasing, low body fat percent is clearly a health problem. The female athlete triad of disordered eating, amenorrhea, and osteoporosis is a relatively new phenomenon. Women athletes, who strive for better performance and lower body weight, often find themselves caught in a negative spiral that actually leads to decreased performance and health risks. Female gymnasts are notorious for getting their body fat down to 2 and 3 percent and male gymnasts, boxers and wrestlers are not far behind usually dropping down to as little as 4 and 5 percent body fat. Eating disorders require special attention and professional assistance…this has been a serious problem for athletes. There have even been steps taken by the National Collegiate Athletic Association to keep wrestlers and gymnasts from going too far when it comes to 'making weight', or reducing their weight to qualify for a lower wrestling weight class.
How Much Fat Is Too Much? Just as too little body fat can create some pretty devastating physiological complications, too much body fat can have equally harmful effects. Once men creep up over 25% and women over 32% fat, there is a dramatic correlation with illness and disease. In fact, body composition has been used more and more to make future predictions about health and disease in individuals. Health risks associated with too much body fat include the following: • increased blood pressure • increased total cholesterol level • increased LDL (bad) cholesterol • increased risk of cardiac problems • increased risk of Diabetes • hardening of the arteries • aggravation of osteoarthritis • promotes blood clots and varicose veins • GI disorders • increased predisposition to some cancers • decreased reaction time • reduced balance and coordination • increased susceptibility to infections • decreased circulation • delayed wound healing
Methods for Assessing Body Composition Measurement of Weight Here is a real toughie… ascertaining some ones weight. Before we even start here note that people lie about their weight about as much as they do about their income taxes and love life. It is a very touchy subject for some people… you might have noticed that if you ever attended a weight watchers meeting. So make sure you do the measuring, and don’t take anyone’s word for what they weigh. Generally speaking, scales based on the lever system are more reliable than spring scales. Both types, however, require periodic inspection and rather delicate handling. Without question the best scales to use are digital scales. No matter what scale you use the subject to be weighed should wear a minimum of clothing, in other words, only gym shorts. Okay, women can wear gym shirts too. While more accurate results are obtained when subjects are weighed in the nude, this often is not practical or desirable. Well, it might be desired some times, but generally there are school rules against such practices. I know they take all the fun out of education. Interestingly, I just read in USA Today that people in the United Sates should have the right to walk around nude… or be weighed in the nude. Personally, I do think people should have the unalienable right to walk around naked or to be weighed in naked if they want to, and those people should be Hollie Berry, Jay-Lo, Brittney Spears, and Madonna. The rest of us need clothes on. Now that I got that off my chest we can continue on. Thank you!
Actually, no appreciable accuracy is lost if the amount of clothing is kept consistent from one weigh-in to the next. Consistency is the key to all measurements. The subject should be weighed at the same time of day and with the same degree of accuracy, usually to the nearest ounce. Once again, note that you cannot distinguish if you are in good physical shape simply by stepping on a scale. A scale simply takes the sum of everything…an absolute weight measurement. Scales can't determine the lean-to-fat ratio of your weight. Actually, and individual could be classified as being overweight but might have very little fat. A bodybuilder, for example, may be as little as 6% body fat, yet at two hundred and fifty pounds may be considered "overweight" by a typical height weight chart. Point in case, a good friend of mine Mark Lund who is a world class bodybuilder had his body fat measured by hydrostatic weighing. As you will discover later on in this chapter hydrostatic weighing is the most accurate method for ascertaining body fat to lean muscle mass. Marks body fat was 4.4% using the aforementioned method. That same day he went to GNC and weighed himself on an electronic foot scale which claimed to measure body fat using a Bioelectrical Impedance method, calibrated with age, height, and weight charts. The scale indicated that Mark was 43 pounds overweight and it printed out a 15 week diet that said he needed to follow immediately if he didn’t want to be a candidate for numerous cardiovascular diseases. Think about that… here was one of the best athletes in the world and this instrument was telling him he needed to lose weight immediately and if he didn’t he was in danger of becoming seriously ill. What does that tell you about scales and height and weight charts? I’ll tell you what it says, these charts are not a good indication of a person's ideal body weight for optimal health, and they certainly are not valid indicators for ascertaining an athlete’s ideal body weight. It should be clear then that the total body weight does not provide an accurate reflection of an individual’s state of health. As just indicated an individual may be classified as seriously overweight, according to standard height and weight tables but yet have perfect body composition. Conversely, a person may have a “normal” weight according to standard tables and yet be overweight or even obese.
Body Fat Scales I know we just got done talking about body fat scales but I need to clarify a few things before we go on. Body fat scales claim to measure body fat quickly and conveniently. The key word in the aforementioned sentence is “claim”. These body fat scales use the Bioelectrical Impedance method to measure your body fat percentage. They do this by passing a low level electrical current through your body and the "impedance", or opposition to the flow of current, is measured. The result is used in conjunction with your weight and other factors to determine your body fat percentage. Unfortunately, your body's "impedance level" can be altered by many factors besides body fat. For instance, the amount of water in your body, your skin temperature and recent physical activity can all adversely affect the results. So only by following strict rules can you hope to get an accurate measurement of your body fat using these scales. The most important rules to observe in order to make a more accurate calculation of your body fat are: • •
Don't eat or drink for 4 hours before the body fat measurement test. Don't exercise for 12 hours before the test.
Some studies have shown variances as high as 8 to 12 percent when using the bioelectrical impedance method even if the rules are precisely followed. These scales use different preprogrammed
equations to calculate body fat from your body density. That should tell you something about the valid of these scales for measuring body fat. We will talk more about bioelectrical impedance method in a moment.