Body composition and weight control. Flashcards
What do body composition measurements find?
The proportion of fat tissue to lean muscle tissue.
What are the 4 main methods of measuring body composition?
Densitometry
Measuring skinfold thickness
Bioelectrical impedance analyisis (BIA)
Simple measurements (BMI, waist:hip, mid-upper arm circumference)
What is the Siri equation?
Equation which uses density to find percentage body fat.
How is body volume found?
Using expensive and sophisticated equipment a such as a Bodpod (measures air displacement) or underwater weighing (body volume equal to difference between land weight and underwater weight).
How do skinfold capillers give a persons density?
Measurements of thickness of skinfolds taken at 4 different sites and used in a formula which takes into account age and sex.
Why is skinfold measurement not an accurate method to determine body density?
Doesn’t take into consideration uneven fat distribution and is a difficult measurement to take.
How does BIA work?
Bioelectrical impedence analysis works by measuring the electrical resistance of the body to a small applied electrical current. Works on the basis that current travels through water so the more fat the less water and more resistance.
What is a major source of error of estimating body fat through BIA?
Hydration of the person is not taken into account. (usually overestimated fat in lean people and underestimates it in obese people)
What does BMI measure?
Body mass index indicates if a person is relatively under or overweight.
Again body composition not taken into account.. what does this result in?
People with a lot of lean tissue are classified as obese
What does the waist to hip ratio indicate?
How much fat is stored around the body organs which is an indicator of heart disease. There can be errors if not the same position is measure for exactly the same person. Want it to be low.
When is the measuring of mid-upper arm circumference used?
In famine relief in measuring who has the least body fat to decide who needs treatment first. Gives a value which is compared to standard values to give a rough estimate of body fat content.
What is obesity characterised by and caused by?
A BMI of over 30, caused by energy-dense diets and low physical activity.
How does an exercise regime increase output energy?
Preserves and increases lean muscle tissue which has a higher BMR.
Increases loss of fat from energy storage so also the percentage body fat decreases.
What is the most effective type of exercise for weight loss?
Aerobic exercise at moderate intensity, frequently and for a long duration. These may however be built up gradually depending on individual’s fitness level.
