Body Composition Chapter 6

The Spectrum of Body Size, Shape and Composition

We All Change in Many Ways

What Is Body Composition? Body composition = the body’s relative amounts of fat mass and fat-free mass (bone, water, muscle, connective and organ tissues, teeth) Essential fat = crucial for normal body functioning 3–5% of total body weight in males 8–12% of total body weight in females Nonessential fat = adipose tissue

Typical Body Composition

Genetics and Body Composition

People come in all sorts of shapes and sizes People come in all sorts of shapes and sizes. Body type or physique can greatly affect performance in different activities. Body type is also known as somatotype. A performer’s somatotype can be measured against the three extreme somatotypes: Endomorph Mesomorph Ectomorph

Somatotypes

Endomorph Extreme endomorphs have the following characteristics: A lot of body fat A lot of fat on the upper arms and thighs Wide hips and narrow shoulders Fairly slim wrists and ankles

Broad shoulders and narrow hips Strong forearms and thighs Mesomorph Extreme mesomorphs have the following characteristics: Very little body fat A muscular body Broad shoulders and narrow hips A large head Strong forearms and thighs

Ectomorph Very little muscle or body fat Narrow hips and shoulders Extreme ectomorphs have the following characteristics: Very little muscle or body fat Narrow hips and shoulders Thin legs and arms A narrow chest and abdomen Thin face and high forehead

What would a person with this score look like? Which somatotype? All performers are made up of elements of these three extreme somatotypes. Most people have a mixture of mesomorphic, endomorphic and ectomorphic characteristics. A person’s somatotype can be graded using a scoring system. They are given 3 scores between 1 and 7, according to how well they conform to each of the extreme somatotypes. 1 is a low score, 7 is a high score. For example: Suggested answer: They would be muscular with little body fat. 1, 7, 2 Low ectomorph Low endomorph High mesomorph What would a person with this score look like?

Mesomorph The mesomorphic shape is the most common body shape among elite performers. Most sports favour the strong, muscular limbs and low body fat of the mesomorphic shape. © EMPICS Ltd The Australian swimmer, Ian Thorpe, has a classic mesomorphic body shape.

Which somatotype?

Somatotypes in sport Certain somatotypes tend to be found in certain sports. The ideal somatotype for a performer will depend on their sport or event. In some cases, the position that they play in a particular sport might also be important. Consider, for example, the various body sizes and shapes in a rugby team.

Somatotypes in sport

Altering body shape Body type is largely determined by the genes you inherit from your parents. However, you can alter your somatotype by training, or by changing your diet. Eating more and/or exercising less will increase your body fat, making you more endomorphic. Weight training will increase muscle size, making you more mesomorphic. Eating less and/or exercising more will decrease your body fat, making you more ectomorphic. Dramatically changing your body shape is difficult and can be damaging to your health. Big changes are hard to maintain.

Weight Every individual has their own optimum weight – the weight at which they are healthy and able to perform at their best. Your optimum weight depends on a number of factors: Height – In general, the taller you are, the more you should weigh. Sex – Men usually have a higher optimum weight than women of the same height. Bone structure – Some people have bigger bones and are naturally heavily built, without being overweight. Image © 2006 Jupiterimages Corporation Muscle girth – People with big, well-developed muscles can weigh a lot without being overweight.

Overweight and overfat A person who is significantly heavier than their optimum weight is classed as overweight. Being overweight is not necessarily harmful as it is possible for the extra weight to be in the form of muscle. However, if the extra weight is in the form of fat, then the person is classed as overfat. This means that an abnormally large percentage of their body is composed of fat. Men are overfat if more than 19% of their body is fat. Women are overfat if more than 25% of their body is fat. Being overfat can affect your health, increasing your risk of heart disease and other illnesses.

Obesity Obese people are people who are extremely overweight. Men are obese if more than 25% of their body is fat. Women are obese if more than 30% of their body is fat. Obesity is very damaging to health. As well as heart disease, obese people run a higher risk of diabetes, varicose veins, menstrual disorders, infertility, skin diseases, liver disorders, cancer, joint problems and even depression. Very obese people can be classed as morbidly obese, meaning that they are so overweight that it is endangering their life.

Obesity © EMPICS Ltd Being obese does not stop you from becoming a successful performer in some sports. Andy Fordham was World Darts Champion in 2004.

Underweight Being significantly below your optimum weight can also be bad for you. The body needs some fat reserves – underweight individuals have a lower resistance to infection and can find it difficult to recover from illness. They may feel constantly tired and bone strength may deteriorate. Underweight women can have trouble getting pregnant. It is recommended that: men should not have less than 5% body fat. women should not have less than 10% body fat.

Weight charts A rough way to determine whether someone is overweight or not is to use a height-to-weight chart. The results are fairly arbitrary and take no account of muscle bulk and frame.

A BMI of 19–25 is considered healthy. Body Mass Index (BMI) Another way of estimating body fat is to calculate an individual’s body mass index (or BMI). BMI is calculated by dividing the individual’s weight (in kilograms) by their height (in metres) squared. To Convert: weight (kg) 154 lbs x 1 kg__ = 70 kg 2.2 lbs Math is great! BMI = height2 So, a person who weighs 70 kg and is 1.70 m tall has a BMI of: 70 = 24.2 1.702 A BMI of 19–25 is considered healthy. Over 30 is obese.

Body Mass Index (BMI) BMI is not an appropriate test for everyone. It is calculated using a person’s height and weight only, so like the chart, the result does not take account of build and lifestyle. Why do you think that a bodybuilder might be classed as too heavy by a BMI test, despite having very little body fat? Under what circumstances could a person with too much body fat be classed as normal by a BMI test? Answers: People who carry a lot of muscle can be classed as overweight by a BMI test, because the muscle makes them unusually heavy for their height. These people are not actually overweight. A person with a lot of body fat could be classed as normal if they have very little muscle.

Excess Body Fat and Wellness Increased risk of chronic disease and premature death; associated health problems include Unhealthy blood fat levels Impaired heart function Heart disease and hypertension Cancer Impaired immune function Gallbladder disease Kidney disease Skin problems Sleeping problems

What shape are you?

Body Fat Distribution and Chronic Disease Location of fat is important to health People who gain weight in the abdominal area = “apples;” this group has an increased risk of coronary heart disease, high blood pressure, diabetes, and stroke People who gain weight in the hip area= “pears”

Problems Associated with Very Low Levels of Body Fat Too little body fat is associated with reproductive, circulatory, and immune system disorders Less than 10–12% for women Less than 5% for men

Female Athlete Triad A condition consisting of three interrelated disorders

Estimating Percent Body Fat Skinfold measurements: Folds of skin are measured with a caliper. The measurements are used in equations that link the thickness of skinfolds to percent body fat calculations made from more precise experiments.

Estimating Percent Body Fat Underwater weighing: An individual is submerged and weighed under water. Percentages of fat and fat-free weight are calculated from body density. The Bod Pod: The amount of air displaced by a person in a small chamber is measured by computerized sensors. Bioelectrical impedance analysis (BIA): A small electrical current is sent through the body, and the resistance of the body to it is recorded. The resulting estimates of how much water is in the body can be used to determine body composition.

Assessing Body Fat Distribution Disease risk increases with total waist measurement of more than 40 inches for men 35 inches for women Disease risk increases with total waist-to-hip measurement above 0.94 for young men 0.82 for young women

Setting Body Composition Goals If fat loss would benefit your health, set a realistic goal in terms of percent body fat or BMI If you have underlying health issues, check with your physician before setting a goal A little weight loss at a time can be very beneficial; focus on a healthy lifestyle including proper diet and exercise