Applied Exercise Physiology Exam IV Study Guide Exam date April 18 2013 Chapters 28 body composition Chapter 30 exercise and weight control 1 Know and understand the principle of Archimedes and how it applies to the procedure of human body volume measurements Archimedes Principle an object s loss of weight in water equals the weight of the volume of water displaced It s specific gravity refers to the mass of an object in air divided by its loss of weight in water Human Model Accounts for water temp residual volume RV in lungs density of water 2 compartments 1 00 fat 0 90 muscle 1 10 Density Mass Volume 2 Understand the differences and usefulness of different body composition and anthropometric assessment procedures discussed in the text and class What are the general assumptions used by indirect measures Anthropometric discussed below Indirect measurements have a certain degree of error In the android type of obesity the person stores fat around his or her abdominal region As such these individuals are usually pictured as having an apple like body shape Based on a study conducted by the Food and Nutrition Research Institute those who are android obese are more at risk of having illnesses related to obesity like heart disease metabolic syndrome and diabetes In addition the likelihood of developing gout arterial related diseases as evidenced by heightened blood pressure and many kinds of cancers are linked to this central type of fat distribution Gynoid type of obesity or fat distribution excess fat are being deposited somewhere at the hip and thigh areas Their hips are rounded and their buttocks generally look larger than normal Thus people who are gynoid obese are called pear obese because they have a body form that looks strikingly similar to the shape of the pear Gynoid obese individuals are said to be at a much safer position than the android obese individuals for they are less at risk in developing chronic illnesses linked to obesity and overweight 3 What are the body composition differences between males and females Men 15 Total Fat 3 Essential Fat 12 Stored Fat Women 25 total Fat 12 Essential Fat 14 Stored Fat 4 Understand the difference between essential and storage fat and the difference between FFM and LBM Essential Fat Fat in lungs heart liver spleen kidneys intestines muscles and the lipid rich tissue of the nervous system and bone marrow We need this fat for normal function For reproduction purposes Women have more fat than men Storage Fat fat deposited in adipose tissue Fat Free Mass any mass in the body that doesn t have fat ie bone muscle water Lean Body Mass is also any fat free mass but it usually refers mostly to lean muscle 5 How does energy balance and weight loss affect body composition When Energy input surpasses Energy Output weight gain occurs and vice versa Things that may effect the balance of energy after you eat are Basal Metabolic Rate Thermic Effect of Food and Physical Activity 6 Understand the potential impact of diet and exercise on obesity e g what are the differences of dieting alone as compared to dieting and exercise combined Exercise alone without dieting If you exercise but still eat too much exercise will help maintain increase absolute fat free mass but your total mass will increase as well therefore your body fat percentage will not change much if at all Dieting alone without exercise If you take in less fat and have a negative caloric balance due to strict dieting with no exercise you will lose total body mass including absolute fat mass AND fat free mass Therefore your percent body fat may not be different In fact it may actually be higher Exercise and dieting combined The effects of exercise and dieting combined have been shown to decrease body fat percentage better than exercise or dieting alone This is due to decreased fat intake plus increased muscle mass For someone who has never exercised it is important to start out slow while still pushing the body to exercise 30 minutes for 4x per week are recommended 7 Understand the concept of the energy balance equations 3500 calories 1 lb of fat Energy Input Energy Output Total Energy Total Energy Intake Total Energy Expenditure After age 26 our BMR slows down by 1 2 every year after that 8 Know the changes that occur in fat cells during weight gain and weight loss With weight loss fat cell sizes and number decrease dramatically when compared to someone who is obese When one is over weight yet loses weight the number of adipocytes does not change substantially yet they do become significantly smaller Therefore people with more hypertrophic fat cells are more likely to beat obesity With weight gain there is a significant increase in fat cell number and size Adipocyte tissue mass increases by hypertrophy size and hyperplasia number Both increase exponentially with weight gain although number increases at a higher rate 9 What is BMI BMI Body Mass Index body mass Kg Stature m 2 Fails to distinguish between body fat muscle mass or bone density so there s a 5 error Classifications Underweight 18 5 kg x m 2 Normal 18 5 24 9 Overweight 25 29 9 Obese class I 30 34 9 class II 35 39 9 class III 40 or greater 10 What are the common techniques used to assess body composition Direct Measurements High accuracy by chemical analysis of the animal carcass or human cadaver One technique dissolves the body in a chemical solution to determine its mixture of fat and fat free components Other technique physically dissects fat fat free adipose tissue muscle and bone Indirect measurements mostly clinical and laboratory procedures 1 Anthropometrics refers to using height weight circumferences and skin folds to estimate the body s comp measurements 2 Hydrostatic weighing Desitometry or UWW Considered the Gold Standard for Based on Archimedes Principle Specific Gravity or Body Density you measure the whole body density using the ratio of body mass and body volume 3 Bod Pod determines body volume by measuring initial volume when pod was empty and then with person inside it Hydration level affects its accuracy Hypohydration and hyperhydration alter the body s normal electrolyte concentrations Hyperhydration overestimates body fat percentage as hypohydration underestimates body fat percentage Skin temperature affects whole body resistance and thus the bioelectrical impedance prediction is altered Warm environment results in a lower predicted body fat while cold environment produces a higher prediction 4 DEXA Radiation
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