Nutrition Chapter 14
cannot be accurately determined from the information provided
A center fielder of a major league baseball team is 188 cm (6 ft 2 in.) tall and weighs 81 kg (180 lb). Is he at his ideal playing weight? -yes -no too light -cannot be accurately determined from the information provided -no, too fat
200 (or about 90-91 kg)
A football player who weighs 250 lb (113 kg) is shown by the skinfold technique to have 20% body fat. He would therefore have ____________ lb (kg) of fat-free mass
true
Air displacement plethysmography has been shown to provide reasonably precise measurements of body volume. -true -false
underwater weighing
Body density is measured directly by -electrical impedence -skinfolds -underwater weighing -radiography
buoyancy
Body fat might be of some benefit to swimming performance because it increases the body's _____________.
dual energy x-ray absorptiometry
DXA stands for -dual-energy X-ray absorptiometry -digital X-ray absorption -direct X-ray analysis -direct X-ray absorption -dual X-ray analysis
measuring the subjects vital capacity
Densitometry has several sources of error. Which of the following is not a common source of error when using this technique to determine body composition? -measuring the subject's vital capacity -interindividual variability in the amount of air in the gastrointestinal tract -interindividual variability in the density of the individual lean tissue compartment -measurement of residual volume -measuremement of V/od/o2 max
Skinfold Calipers are used to assess body composition. They measure the skinfold thickness at various sites of the body. Bioelectrical Impedance is also another method for measuring body composition. it measrues conductivity through different tissues.
Describe two field techniques for assessing body composition and the principles behind their operation.
Body size refers to the volume, mass, length, and surface area of the body. Body composition refers to the amounts of the constituents in the body. These are all separate but interrelated aspects that make up the physique.
Differentiate between body size and body composition. How does each of these relate to an athlete's performance?
1% to 3%
Even with the best laboratory techniques, measurement of body density can introduce an error of __________, and even greater error is associated with converting that density to relative body fat. -10% to 12% -4% to 6% -1% to 3% - 5% to 8%
all statements are correct
Generally, excessive body fat impairs athletic performance in activities in which body mass must be moved through space. Which of the following is an exception to this fact? -heavy weightlifters who increase body fat before competition to gain a mechanical advantage by lowering the center of gravity -sumo wrestlers -swimmers because body fat improves buoyancy and decreases drag -all statements are correct
cognitive function
Higher relative body fatness is not associated with poorer performance on tests of -speed -endurance -balance -cognitive function -agility
false
If a small weight loss improves a person's performance, then a major weight loss will improve performance even more. -true -false
false
Imaging techniques, including magnetic resonance imaging, computed tomography, and bioelectrical impedance, can be used to visualize fat depots in the human body. -true -false
water
In the densitometry method of body composition analysis, the density of the body is compared to the density of -fat -water -muscle -bone -alcohol
true
Maximizing the fat-free mass of the athlete is desirable for athletes involved in activities that require strength, power, and muscular endurance. -true -false
false
Skinfolds are the most accurate way to measure body fat as long as the fold thickness is not converted to a percentage body fat. -true -false
water
Some of the error in estimating body fatness from body density measurements is related to the variability in the density of -water -the fat mass -the lean mass -subcutaneous fat components -extracellular fluid
a and c
The Siri equation is used to convert body density to an estimate of relative percentage body fat and assumes that -the densities of the fat mass and the fat-free mass are relatively constant in all people -the relative density of fat is generally 1.1 g/cm3 -the density of each tissue constituting the fat-free mass is known -the density of each tissue constituting the fat-free mass varies by a standard and accountable amount - a and c
air plethysmography
The densitometric technique to measure body density using air displacement is -bioelectrical impedence -air plethysmography -air immersion -air conduction -bioelectrical immersion
inaccurate assumption of the density of the fat-free mass
The most significant problem in obtaining an accurate evaluation of a person's body composition using densitometry is -inability to obtain an accurate weight underwater -inaccurate assumption of the density of fat -inaccurate assumption of the density of the fat-free mass -none, because the technique is always highly accurate
Densitometry was developed to measure body composition. Using underwater weighing, or hydrostatic weighing, a person is submerged in water and body weight is accurately measured before and after submersion. There are many weaknesses with this method such as the composition of FFM can change after weight training. Measurements are also taken after the person has made maximal exhalation which could exert a buoyancy effect. There also could be residual volume that remains in the lungs. Food intake cann also affect measurement.
What is densitometry? How is it used to assess the body composition of the athlete? What is the major weakness of densitometry with respect to its accuracy?
Relative leanness and fatness depends on the sport you are performing. In sports where you need a lot of weight such as heavy lifting, extra fat is needed. Some sports such as ballet need more leanness in their athletes. It depends on what activity the person is performing.
What is the relationship of relative leanness and fatness to performance in sport?
Fat free mass includes most of the bodys organs, muscle tissue, bone, connective tissue and water
What tissues of the body constitute the fat-free mass?
BMI is calculated as weight (in kilograms) squared divided by height (in centimeters).
Which of the following is false? -BMI is calculated as weight (in kilograms) squared divided by height (in centimeters). -BMI provides useful information about risks for various diseases and is used in many epidemiological and clinical studies. -BMI correlates with the incidence of cardiovascular complications (hypertension and stroke). -BMI is best used for populations rather than individuals. -BMI is best combined with waist circumference or body composition measurements.
electrical conductivity is much greater in the fat mass than in the fat free mass
Which of the following is incorrect concerning bioelectrical impedance? -Electrical conduction through the tissues between electrodes depends on the water and electrolyte distribution in that tissu -Electrical conductivity is much greater in the fat mass than in the fat-free mass. -The amount of current flow through the tissues reflects the relative amount of fat contained in that tissue. -The relative body fat in lean athletic people tends to be overestimated with bioelectrical impedance because of the nature of the equations used.
skinfold thickness
Which of the following methods would you use in a large-scale study to assess body composition? -skinfold thickness -hydrostatic weighing (underwater weighing, or hydrodensitometry) -air displacement plethysmography (Bod Pod) - bioelectrical impedance analysis (BIA) -dual-energy X-ray absorptiometry (DXA)
it assumes standard densities for bone, muscle, and fat
Which of the following statements about underwater weighing is true? -It can divide the body into bone, muscle, and fat components. -It assumes standard densities for bone, muscle, and fat - It can divide the body into visceral and subcutaneous fat components. -It is a direct method of assessing body composition.
false
With the bioelectric impedance technique for estimating body composition, the electrical current moves through the fat tissue at a much slower rate than it does through the fat-free mass because of the lower density of the fat-free mass. -true -false
underwater weighing
___________________________ is currently considered the most accurate method for assessing body composition, even though it is known to have serious limitations.