Body Composition Chapter 4 PDF

Body Composition Chapter 4 Principles and Labs for Fitness & Wellness Werner W. K. Hoeger and Sharon A. Hoeger  The 5 Components of Physical Fitness  Body composition  Cardiorespiratory endurance  Muscular strength  Muscular endurance  Flexibility Bod...

Body Composition Chapter 4 Principles and Labs for Fitness & Wellness Werner W. K. Hoeger and Sharon A. Hoeger  The 5 Components of Physical Fitness  Body composition  Cardiorespiratory endurance  Muscular strength  Muscular endurance  Flexibility Body composition  Fat and nonfat components of human body that are important in assessing recommended body weight  Recommended body weight (healthy weight) is the weight at which there seems to be no harm to human health  Percent body fat is the proportional amount of fat in the body based on the person’s total weight  Lean body mass is the body weight without the body fat Terms used to describe body weight  Overweight Excess amount of weight against a given standard, such as height or recommended percent body fat  Obesity Excessive accumulation of body fat, usually at least 30% above recommended body weight Fat in the human body is classified into two groups  Essential fat: need for normal physiological function  Storage fat: fat stored in adipose tissue and around major organs Functions  Insulator to retain body heat  Energy substrate for metabolism  Padding against physical trauma to the body Assessing body composition  Techniques to measure body composition include: 1. Dual-Energy X-ray Absorptiometry 2. Hydrostatic weighing 3. Air displacement 4. Skinfold thickness 5. Girth measurements 6. Bioelectrical Impedance Dual-Energy X-ray Absorptiometry Description Uses very low-dose beams of x-ray energy to measure total body fat mass, fat distribution pattern and bone density Standard Error of Estimate +/- 1.8% Considerations Takes less than 15 minutes to administer Not readily available due to cost Hydrostatic weighing Description Underwater technique to assess body composition, considered the most accurate of the body composition assessment techniques Standard Error of Estimate +/- 0.5% Considerations Requires up to 30 minutes per person Residual lung volume should also be determined Person must be completely underwater, so difficult for aquaphobic people Air Displacement Description Calculates body volume from the air replaced by an individual sitting inside a small chamber Standard Error of Estimate +/- 2.2% and may be higher Considerations Takes about 15 minutes Consistently overestimates percent body fat More research required to determine accuracy Skinfold thickness Description Measures a double-thickness of skin at specific sites on the body. A three-site procedure is commonly used: Women: triceps, suprailium and thigh Men: chest, abdomen and thigh Standard Error of Estimate +/- 3.5% Considerations Training is necessary to perform assessment accurately Measurements should be taken at the same time of day More research required to determine accuracy Girth measurements Description Measures the circumference of specific body sites Women: upper arm, hip and wrist Men: waist, wrist Standard Error of Estimate +/- 4.0% Considerations May not be valid for athletic individuals or those who appear visually thin or obese Bioelectrical impedance Description Sensors are applied to the skin and run a weak electrical current through the body to measure electrical resistance Standard Error of Estimate Percent body fat may be off by 10 percentage points or more Considerations Accuracy of equations is questionable Hydration and body temperature affect results More research required to determine accuracy Body Mass Index  Technique used to determine the thinness and excessive fatness that incorporates height and weight to estimate critical fat values at which the risk for disease increases BMI and mortality Waist circumference provides information about disease risk  Compared to people with fat stored primarily in the thighs and hips, obese people with abdominal fat are at higher risk for many diseases  Android obesity is seen in individuals who store fat in the trunk or abdominal area  Gynoid obesity is seen in people who store fat primarily around the hips or thighs  Waist circumference is a better predictor than BMI to determine the risk of disease Waist circumference provides information about disease risk Determining your recommended body weight (RBW)  First, use your percent body fat from the previous table to determine your body composition classification  Follow these four steps: 1. Determine Fat Weight (FW): FW = BW x %F 2. Determine Lean Body Mass (LBM) LBM = BW – FW 3. Select a desired body fat percentage (DFP) 4. Compute RBW: RBW = LBW / (1.0-DFP)  Determining your recommended body weight (RBW)  Ahmad is a 100 kg male with %fat of 40. He wants to reduce his %fat to 20%. Calculate Ahmad’s recommended body weight.  FW = 100 kg x 40% = 40 kg  LBM = 100 kg – 40 kg = 60 kg  The desired body fat percentage is 20%  RBW = 60/(1-0.2) = 75 kg Perform regular assessments of body composition  While dieting, exercising or both, repeat assessments monthly  Body composition changes during weight control and exercise activities