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Body Composition. Body Composition. There are three interrelated aspects of the human physique: Size (volume, mass, surface area, length) Structure (skeletal, muscular, fat arrangement and distribution) Composition (amount of fat, muscle, bone)
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Body Composition Sport Books Publisher
Body Composition • There are three interrelated aspects of the human physique: • Size (volume, mass, surface area, length) • Structure (skeletal, muscular, fat arrangement and distribution) • Composition (amount of fat, muscle, bone) • Body composition is one of the major components of physical fitness Sport Books Publisher
Body Composition • Most common method used in body composition analysis is the ‘Two-Component’ model of the body • This model includes: • Lean body mass (LBM) • Fat body mass • Total body fat (TBF) Sport Books Publisher
Lean Body Mass • Refers to the ‘non-fat’ or ‘fat-free’ component of the body • Includes skeletal muscle, bone, water • May represent a biological lower limit beyond which health is compromised • Excessive leanness may increase a female’s chances of developing amenorrhea (absence of menstruation) • Amenorrhea includes a reduced production of estrogen, which may also increase a female’s chances of developing osteoporosis Sport Books Publisher
Lean body mass is calculated as follows: LBM = TBM -TBFLean body mass = Total body mass - Total body fat • TBF is calculated as follows: TBF = TBM x %BODY FAT 100 Sport Books Publisher
Direct Measurement Indirect Measurement Measuring Body Fat Sport Books Publisher
Measuring Body Fat • Involves grinding tissue • Measures fat via chemical analysis • Impractical for living organisms • Used on cadavers Direct Measurement Sport Books Publisher
Measuring Body Fat • Skinfold calipers • Hydrostatic weighing • Bod-Pod • Bioelectrical impedance • DEXA Indirect Measurement Sport Books Publisher
Skinfold Calipers Sport Books Publisher
Skinfold Calipers • Measures skinfold thickness to predict or estimate total body fat • Based on the assumption that subcutaneous fat is directly related to total body fat • Accuracy is ± 3% when performed correctly Sport Books Publisher
YMCA Skinfold Test • Equipment: • Skinfold calipers • Skinfold sites: • Four sites: abdomen, suprailium, triceps, thigh • Calculation of % body fat: Males %fat = 0.29288 x (sum of 4) - 0.0005 x (sum of 4)2 + 0.15845 x (age) - 5.76377 Females %fat = 0.29669 x (sum of 4) - 0.00043 x (sum of 4)2 + 0.02963 x (age) - 1.4172 Sport Books Publisher
Norms for Percent Body Fat Sport Books Publisher
Circumference (Girth) Measurements • Equipment: • A flexible steel or cloth measuring tape • Circumference sites: • Neck, chest, hips, thigh, calf, biceps, abdomen Sport Books Publisher
Body Mass Index (BMI) • Can be used as an easy, inexpensive method for determining an individual’s healthy body weight • Considers weight (kg) and height (m) BMI = Weight (kg) [Height (m)]2 • A BMI nomogram can also be used to determine BMI, it looks like this… Sport Books Publisher
Body Mass Index (BMI) Sport Books Publisher
Body Mass Index (BMI) • Three general ranges: • Underweight • Healthy or Acceptable Weight • Overweight • Severe Overweight • Morbid Obesity • BMI score > 30 is classified as obese and associated with an increased risk of developing health problems • Risk of developing health problems is also associated with BMI’s classified as being within the underweight range Sport Books Publisher
Body Mass Index (BMI) • The BMI is intended for men and women aged 20-65 • It is not intended for: • Babies • Children • Teenagers • Pregnant women • Very muscular people, such as athletes Sport Books Publisher
Bioelectrical Impedance (BIA) • Based on differences in electrical conductivity between fat-free mass and fat mass Sport Books Publisher
Bioelectrical Impedance (BIA) • Percent body fat is calculated from measures of body density determined by passing an electrical current through the body Sport Books Publisher
Bioelectrical Impedance (BIA) • BIA is influenced by the subject’s hydration level • The more hydrated one is, the leaner the BIA measurement will be Sport Books Publisher
Hydrostatic Weighing Sport Books Publisher
Hydrostatic Weighing • Bone and muscle have a greater density than water • Fat is less dense than water • Thus, a person’s relative buoyancy is positively correlated with body fat • That is, a person with a higher body fat percentage is less dense (weighs less in water) than a lean individual Sport Books Publisher
Hydrostatic Weighing • To calculate body fat, the following measurements are needed: • Body weight on land • Underwater body weight • Water density at the performed temperature • Residual lung volume • More accurate measure Sport Books Publisher
The Bod-Pod Sport Books Publisher
The Bod-Pod • Very expensive method • Very accurate measure • May facilitate measuring large or heavy individuals because it does not involve underwater submersion Sport Books Publisher
Dual Energy X-Ray Absorptiometry (DEXA) Sport Books Publisher
Dual Energy X-Ray Absorptiometry (DEXA) • Can be used to determine body composition • Can also measure bone density (bone mineral content) Sport Books Publisher