CH-11-12 Weight and Body Composition – Nutrition for Sport and Exercise : Chapter Notes

This Document Contains Chapters 11 to 12 Chapter 11: Weight and Body Composition Overarching Concepts 1. Body weight and composition can affect performance, appearance, and health. 2. All measurement methods have inherent errors and are only estimates. 3. Results must be interpreted and applied carefully. 4. Realistic goals must be set. 5. Attaining and maintaining body composition changes take time and effort. 6. The “optimal” body composition or weight for excellent performance is not known. Learning Objectives LO 11.1 Describe the various components that make up the body’s composition. LO 11.2 Describe how body composition and body weight are measured, how a measurement error might occur, how these results should be interpreted, and how each relates to performance. LO 11.3 Understand how the relative need for size (weight), strength, and speed in a particular sport is reflected in the body composition of elite athletes in those sports. LO 11.4 Outline the basic principles associated with gaining lean body mass and losing body fat and the most appropriate times during the yearly training cycle to change body composition or weight, and be able to calculate target and minimum body weight. LO 11.5 Discuss the legality, ethics, purity, safety, and effectiveness of musclebuilding and weight-loss supplements. Chapter Outline I. Introduction A. Pre-test assessment B. Introduction to weight and body composition 1. Related to performance, appearance, and health 2. Plays a large role in some sports, lesser role in other sports 3. All measurements are estimates 4. High power-to-weight ratio beneficial in many sports 5. Changes to body composition should be part of periodization plans 6. To change body composition the athlete must alter energy intake, energy output, or both II. 11.1 Understanding weight and body composition • The terms body mass and weight are commonly used interchangeably, although mass technically refers to the amount of matter of an object and weight refers to the force an object exerts due to gravity. • Body composition refers to all of the components that make up the body, particularly fat, muscle, bone, and water. • Body weight and composition may be directly related to performance in certain sports, whereas in others they may be related more to appearance or other factors. • A minimum amount of body fat, referred to as essential, is needed for proper physiological functioning. • Body Mass Index (BMI), a ratio of weight to height, is not an accurate way to characterize body composition in muscular people, and therefore should be used cautiously with athletes. A. it is important to understand the concepts of body mass, weight, and composition 1. Broad definition of body composition includes fat-free mass and fat mass or the ratio of fat mass to total body mass 2. Body mass a. Mass vs. weight b. Weight is affected by gravity 3. Body fat a. Essential 1) approximately 3% in males 2) approximately 12% in females a) Sex-specific (hormonal/reproductive functions) approximately 9% b. Storage fat 1) Subcutaneous fat 2) Visceral fat 3) Common gender distribution a) Android (male) (1) Abdominal area (2) “Apple” shaped b) Gynoid (female) (1) Hips, thighs, buttocks (2) “Pear” shaped c) Gender not the only influence 4. Fat-free mass (FFM) a. Muscle, bone, fluids, organs b. Difficult to measure c. Lean body mass (LBM) 1) Fat-free mass + essential body fat 2) Easier to measure than FFM 3) Muscle is one component of LBM 5. Body shape a. Somatotype (body build) 1) Endomorph a) “Stocky” with wide hips b) Easily gains body fat 2) Ectomorph a) Slightly built b) Difficulty gaining weight or LBM 3) Mesomorph a) Muscular with little excess body fat b) Easily gains LBM b. General categories recognize genetic predisposition 6. Body Mass Index (BMI) a. Relationship of weight to height b. Used to establish a “healthy weight” range c. Risk assessment tool for the general population d. Not appropriate to use with: 1) Pregnant females 2) Trained athletes 3) Those with osteoporosis 7. Models for determining body composition (see Figure 11.8, page 414 for an illustration of 2-, 3-, and 4-compartment models) a. Two-compartment model 1) Fat mass (FM) + FFM 2) Not all FFM tissues have the same density b. Three-compartment model 1) FM + bone mass + FFM 2) Measuring bone mass increases accuracy c. Four-compartment model 1) FM + bone mass + FFM + total body water 2) Most accurate due to measurement of more types of tissues 3) DEXA Question for discussion: How is it possible for two athletes to have the same height, weight, and BMI but different body composition? III. 11.2 Assessment and interpretation of weight and body composition • All assessments of body composition are estimates, with varying degrees of accuracy. • Each body composition assessment technique has some inherent error as well as varying potential for technical or measurement error. • Underwater weighing and air plethysmography determine the volume and density of the body, which is then used to predict body composition or percent body fat. • The thickness of skinfolds, including subcutaneous fat, from specific sites on the body is used in either generalized or population-specific prediction equations to estimate body composition. • Body composition is estimated using BIA by using the difference in electrical conduction properties between fat and other tissues in the body. • DEXA uses X-ray to determine bone density, which allows for body composition estimation using the four-compartment model. • DEXA is becoming the gold standard for body composition assessment for research but is not widely available or practical for use with large numbers of athletes. • The use of body composition results must keep in mind the error associated with the assessment method. • Consistent use of body weight over time can be used to track hydration status, changes in muscle mass, body fat, and so on. A. Body weight is measured with a scale 1. Balance beam or digital scale a. Calibrate monthly b. Record to the nearest 0.5 lb or 0.2 kg c. Repeated measurements should be on same scale under same conditions (e.g., time of day) d. Keep information confidential unless disclosed by terms of sport B. Body composition can be estimated by a variety of methods 1. Comparison of methods a. Accuracy b. Practicality and portability c. Ease of use d. Time e. Cost f. Subject comfort and effort g. Technician training 2. Error of measurement a. Body fat is not measured directly b. All methods have inherent error c. Technicians and subjects can add more error d. Standard Error of the Estimate (SEE) 1) If SEE is 2.7%, 2/3s will have body composition +/- 2.7% 2) 1/3 of people measures will have body composition outside of that range 3) Body fat percentages expressed in two or three decimal places suggest a degree of measurement precision that is unrealistic 4) Table 11.1, page 416 Comparison of Methods Used to Estimate Body Composition C. Underwater weighing and plethysmography estimate body composition by determining body density 1. Hydrodensitometry or underwater weighing a. Ratio of mass (weight) to volume b. May be most accurate measure available to athletes c. SEE = approximately 2.7% d. Practical if space is available e. Requires submersion in water, holding breath f. Takes more time to perform than most methods g. Subject may be uncomfortable h. Technician training needed but not difficult i. Expensive to purchase 2. Plethysmography a. Uses air displacement to measure volume b. SEE = approximately 2.2 to 3.7% c. Practical if space is available d. Takes approximately 5 min f. Subject may be uncomfortable being enclosed g. Finite space for very large or tall athletes h. Minimal technician training needed i. Expensive to purchase D. Body composition can be estimated using the thickness of skinfolds from specific sites on the body 1. Estimates subcutaneous fat stores 2. SEE = approximately 3.5% 3. Practical if private area is available 4. Takes approximately 5 min 5. Subject may be uncomfortable; some measurements difficult 6. Technician training and skill are critical 7. Electronic calipers available 8. Inexpensive to purchase calipers E. Bioelectrical impedance analysis (BIA) uses electrical currents to estimate the proportion of fat in the body 1. Based on electrical current conductivity 2. SEE = approximately 3.5% 3. Practical and easy 4. Takes approximately 5 min 5. Pre-measurement guidelines require substantial subject compliance 6. Hydration status can interfere with accuracy of results 7. Technician training is minimal 8. Moderately expensive to purchase F. A beam of near-infrared light is used to distinguish between fat and other tissues – Near-infrared interactance (NIR) 1. Based on absorption and reflection of light 2. SEE = approximately 4 to 5% 3. Practical and easy 4. Takes approximately 5 min 5. Simple procedure 6. Technician training is minimal 7. Moderately expensive to purchase G. Dual-energy X-ray absorptiometry (DEXA or DXA) uses low-intensity, focused X-rays to determine bone density and estimate body composition 1. Based on low-intensity X-rays 2. SEE = approximately 1.8% but more research needed to confirm 3. Practical in some facilities; easy to use 4. Takes approximately 5 to 10 min 5. Simple procedure 6. Subject exposed to very small amount of radiation 7. Technician training and licensure needed 8. Provides fat mass, lean mass (including bone density) 9. Very expensive to purchase H. Advanced imaging techniques include CT scans and MRI – Computed tomography scans (CT) and magnetic resonance imaging (MRI) 1. Imaging techniques 2. SEE not yet established 3. Practical in some facilities 4. Takes approximately 30 min; subject must be still 5. Technician training and licensure needed 6. Very expensive to purchase I. Body composition results must be interpreted appropriately 1. Results should be given as a range 2. May be used to determine an appropriate body weight goal J. Body weight results must be interpreted appropriately and used consistently 1. Most useful for tracking hydration status 2. Necessary to measure if weight must be certified 3. Most athletes do not need to measure weight daily 4. Must be interpreted correctly a. Decreased body weight could result from: 1) Loss of water (dehydration) 2) Loss of body fat (kcal deficit) 3) Loss of muscle mass (starvation) Questions for discussion: (1) What body composition assessment method would you use for determining percent body fat in a group of athletes for a research study? How about for preseason and postseason measurements? (2) What would you tell an athlete who is concerned because at the end of a strenuous 2-week training camp his or her percent body fat remains the same? IV. 11.3 Body composition and weight related to performance • The sport and position played and the relative need for power and endurance are factors in establishing an optimal performance weight and body composition. • In sports with weight categories, a higher body weight relative to the weight class and a higher power-to-weight ratio may be a competitive advantage. • Weight and body composition goals may be influenced by appearance, particularly in sports that are subjectively scored or the body is judged. • Although weight and body composition may be similar among elite athletes in certain sports, these figures should be used with caution by an individual athlete who must consider his or her unique characteristics and genetic predisposition. A. Certain physical characteristics are associated with sports performance 1. Depends on sport, position played, size requirements, relative need for power, weight certification, body appearance 2. Sport played a. In some sports, excess body fat is “dead weight” b. In some sports, body composition plays minor role 3. Position played 4. Physical size – Size may be the most important factor (e.g., sumo wrestling, ski jumping) 5. Relative need for power and endurance a. High power-to-weight ratio important for explosive power b. Low percentage body fat may be beneficial if weight must be moved 6. Weight certification 7. Physical appearance – Spotlight on... Athletes and Appearance—Meeting Body Composition Expectations 8. Body composition must be determined on a case-by-case basis B. Many athletes establish weight and body composition goals in an effort to improve performance or health 1. Table 11.2, page 428 Estimated Body Fat Ranges for Athletes in Selected Sports Question for discussion: The percentage of body fat of professional distance cyclists is often reported as being between 7 and 10 percent. Why might reaching this range be beneficial or detrimental for a cyclist? V. 11.4 Changing body composition to enhance performance • Many athletes seek to change body weight or composition as a way to improve performance. • Once body composition goals are established, an athlete can estimate a target weight that reflects those goals. • To increase skeletal muscle mass, the athlete must engage in a resistance-training program that is supported by sufficient energy and nutrient intake. • To decrease body fat, the athlete must increase energy expenditure, decrease energy intake, or both. • The process of losing weight as body fat also results in the loss of lean body mass. To protect skeletal muscle mass from being lost, it may be prudent to consume a higher protein (but still energy restricted) diet. • The timing of weight and body composition changes is important so that neither training nor performance is negatively affected. A. Desired body composition can be used to determine a target weight 1. General considerations a. Body composition must be estimated as accurately as possible b. Must consider genetic predisposition, requirements of the sport c. Realistic goals, achievable through diet and training d. Attaining or maintaining goals does not put athlete’s health at risk e. Target body weight formula B. Body composition can be changed by increasing muscle mass 1. Role of exercise a. Periodized strength training b. Hypertrophy phase 1) Large volume (number of sets and repetitions) 2) Moderate intensity or load (amount of weight lifted) 3) Amount of increase of muscle mass is in response to strength training is dependent on several factors 2. Role of nutrition a. Sufficient energy intake b. Sufficient protein intake 1) In positive nitrogen balance c. “Rule of thumb” estimates to support resistance training program 1) Additional approximately 400 to 500 kcal daily 2) Additional approximately 14 g protein daily C. Body composition can be changed by decreasing body fat 1. General principles a. Must create a caloric deficit 1) Decrease kcal intake by reducing food intake 2) Increase energy expenditure 3) Combination of both recommended 2. Role of exercise a. Used to create moderate caloric deficit b. Maintains or minimizes loss of LBM c. Athletes may not be able to increase exercise substantially due to increased risk for injury or overtraining 3. Role of nutrition a. Do not restrict daily intake to 6 months will likely affect bone mineral density 5. Many athletes view this as being advantageous D. Low bone mineral density is a third factor involved in the Female Athlete Triad – Osteopenia and osteoporosis 1. Low bone mineral density and structural deterioration (osteopenia) 2. Result of low estrogen concentration 3. Greater risk for stress fractures 4. Early intervention is important E. Both elite and recreational athletes can develop the Female Athlete Triad – Prevalence 1. Hard to determine 2. Any physically active female is at risk for the triad 3. Elite athletes may be at greater risk F. Prevention, intervention, and treatment of the Female Athlete Triad are critical 1. General characteristics a. Screening is very important b. Some sports are considered high risk (e.g., distance running) c. Early intervention is critical 2. Role of coaches a. Establish a culture that supports normal eating b. Refer to a sports dietitian G. Spotlight on... Normal Bone Density in a Former Amenorrheic, Osteoporotic Distance Runner Question for discussion: Why might a female collegiate cross country runner say to her teammate, “If you’re still menstruating, then you’re not training hard enough”? Why, in fact, is this approach dangerous? V. Summary and review A. Chapter summary B. Post-test assessment C. Review questions D. References Supplementary Teaching Materials and Classroom Activities Note: The text chapter includes an application exercise featuring the SCOFF Eating Disorder Quiz screening tool (p. 462). Activity 12-1 Guest speakers who have experienced disordered eating or eating disorders can provide tremendous insight for students. However, it is important that such speakers are fully recovered from their disordered eating and exercise patterns. Most of the speakers will be many years removed from their eating disorder experiences. Such speakers are usually comfortable with any questions that students may ask, but it is important to set the ground rules—questions should be asked respectfully and the speaker may decide not to answer a particular question. If the university has an eating disorder team or task force assembled, these professionals can give presentations on prevention, intervention, and treatment. Crossword Puzzle Answer Key 1. psychiatric 2. muscle dysmorphia 3. amenorrhea 4. emaciated 5. prevalence 6. anorexia nervosa 7. eating disorder 8. enema 9. obsession 10. discipline 11. bulimia nervosa 12. fasting 13. cycling Word Find Puzzle Answer Key • 4 qualities of a normal diet: moderate, balanced, varied, flexible • 3 eating disorders recognized by the APA: anorexia nervosa, bulimia nervosa, EDNOS • 2 types of AN: restricting, binge-eating/purging • 2 types of BN: purging, nonpurging • 6 sports associated with a high risk of disordered eating: bodybuilding, gymnastics, horseracing, running, ski jumping, swimming • 3 components of treatment for anorexia athletica: psychological, nutritional, medical • 3 problems associated with the Female Athlete Triad: disordered eating, amenorrhea, osteoporosis P F L E X I B L E A D E I R A V R S G T I B U L I M I A N E R V O S A C W N L E M A N P A R T S I C L E M N A I I B L A C I G O L O H C Y S P N O D M G O O A I D E C N A L A B N G T R G M R D G M H T H D I N G S T H A T E Y I U Y N E P R E S T R I C T I N G X M N P B I N G E E A T I N G P U R G I N G A U G O S T E O P O R O S I S N A A R T I R R I C E T A R E D O M L I N S E L L U R S C A N W H A T S H E N E T L A D P H O R S E R A C I N G I N R I K C I N E E I T S N O T I M P O U V C R I N O A G N I T A E D E R E D R O S I D G N R T A N G N I P M U J I K S T P E A N U T R I T I O N A L R T I A C L M Chapter 12 Crossword Puzzle Across Down 2. Pathological preoccupation with gaining muscle mass. 5. The number of cases of a condition that exists in the population at a given point in time. 7. Substantial deviation from normal eating, which meets established diagnostic criteria. 8. Insertion of a liquid via the rectum to induce a bowel movement. 11. An eating disorder characterized by bingeing and purging cycles. 12. Abstaining from food or drink. 13. Weight _____ entails repeated weight loss and weight gain. 1. Relating to the medical specialty concerned with the diagnosis and treatment of mental or behavioral disorders. 3. Absent or suppressed menstruation. 4. Extremely thin. 6. A life-threatening eating disorder characterized by a refusal to maintain a minimum body weight. 9. Idea or feeling that completely occupies the mind; sometimes associated with psychiatric disorders. 10. Moderate self-control or restraint. Chapter 12 Word Find Puzzle P F L E X I B L E A D E I R A V R S G T I B U L I M I A N E R V O S A C W N L E M A N P A R T S I C L E M N A I I B L A C I G O L O H C Y S P N O D M G O O A I D E C N A L A B N G T R G M R D G M H T H D I N G S T H A T E Y I U Y N E P R E S T R I C T I N G X M N P B I N G E E A T I N G P U R G I N G A U G O S T E O P O R O S I S N A A R T I R R I C E T A R E D O M L I N S E L L U R S C A N W H A T S H E N E T L A D P H O R S E R A C I N G I N R I K C I N E E I T S N O T I M P O U V C R I N O A G N I T A E D E R E D R O S I D G N R T A N G N I P M U J I K S T P E A N U T R I T I O N A L R T I A C L M Instructions: In the grid above, find the following words or phrases, and then write them beside each clue. • 4 qualities of a normal diet: • 3 eating disorders recognized by the APA: • 2 types of AN: • 2 types of BN: • 6 sports associated with a high risk of disordered eating: • 3 components of treatment for anorexia athletica: • 3 problems associated with the Female Athlete Triad: Instructor Manual for Nutrition for Sport and Exercise Marie Dunford, J. Andrew Doyle 9781285752495 1 Crossword and word find contributed by Elesha Feldman