Sports Medicine Body Composition

Objectives Define terminology related to body composition Determine factors influencing body fat Identify ideal levels of body fat Explore different methods of calculating body composition

Terminology: Body composition – the makeup of the body tissues, including muscle, bone, fat and other tissues Skinfold measurement - layers of fat under the skin that are measured to estimate body fat Skin caliper - a device used to measure the amount of fat beneath the skin Percent body fat – the amount of fat in a person, expressed as a percentage of total weight

Body Composition Typical person Lean body tissue = 75 to 85 % Includes muscle, bone, skin, organs (heart, liver, kidneys, lungs, etc.) Fat = 15 to 25 % A low percentage of body fat is desirable; however, some body fat is essential Insulates – helps body adapt to heat or cold Shock absorption – protects organs/bones from injury Source of stored energy Helps body use vitamins effectively

Factors Influencing Body Fat Heredity Metabolism Aging Amount of body fat when 2 years old Diet Physical Activity

Ideal Levels of Body Fat Essential body fat: minimum amount of body fat to avoid health problems Teenage girls: Between 11 and 25 percent Obese = 35+ percent Teenage boys: Between 6 and 20 percent Obese = 30+ percent

Health Risks of Being Obese High blood pressure High blood cholesterol Coronary heart disease Stroke Diabetes Some types of cancer (endometrial, breast, prostate & colon) Sleep apnea & breathing problems

Health Risks of Being Too Skinny Eating disorders Anoreixa Bulimia Abnormal menstruation in females Loss of bone density Higher incidence of injuries

Methods of Assessing Body Fat Hydrostatic Weighing BodPod Skinfold Measurements Body Measurements Body Mass Index Height-Weight Charts Waist-to-Hip Ratio

Hydrostatic Weighing Based on the fact that lean mass (bone, muscle, connective tissue) sinks while body fat floats Weight is taken on land Lung capacity is also measured to account for air in the lungs Person is immersed in a tank of water & then weighed A formula applied to underwater weight & lung capacity to determine body fat + very accurate - requires time, money and expertise https://www.youtube.com/watch?v=QslL-PqOs2s

Bod Pod A machine that measures weight (mass) Uses air to measure volume (change in pressure) Calculates density (mass/volume) Takes into account the air in the lungs + very accurate - limited availability https://www.youtube.com/watch?v=FoGHJAj32W4

Skinfold Measurements Caliper is used to measure skinfolds at certain sites Females: triceps + hips + thigh Males: chest + abdomen + thigh Amount of body fat is determined using age and sum of skinfold measurements + easy - less accurate https://www.youtube.com/watch?v=ilkwxlt_TA8

Body Measurements Body measurements are used to estimate a person’s percentage of body fat Females = height & hip Males = weight & waist Using a chart, line up the body measurements in the two side columns and determine the percent body fat value in the middle column

Body Mass Index (BMI) Indicator of body composition Take the following measurements: Height: measured in inches, without shoes Weight: measure in pounds, without shoes and minimal clothing Check chart to find BMI rating Not very accurate https://www.youtube.com/watch?v=aCsZsFt7Pwg

Height / Weight Charts Method to estimate percent body fat Comparison between a person’s height and weight Obtain the measurements as follows: Weigh the person on an accurate scale with shoes removed and minimal clothing Measure the person without shoes Then compare the two measurements The ideal ratio is 2:1 or greater

Waist-to-Hip Ratio Method to estimate percentage of body fat Comparison between the circumference of a person’s waist and a person’s hips Waist circumference: measure the person’s waist at the level of the navel Hip circumference: measure the person’s hips at the widest point Using a chart, line up the body measurements in the two side columns and determine the percent fat value in the middle column https://www.youtube.com/watch?v=sEFKdNR9boQ

https://www.youtube.com/watch?v=fWI2KL9QSWg