Exercise Physiology Exam 4 1 1 Know and understand the principle of Archimedes and how it applies to the procedure of human body volume measurements This is the trick that Archimedes found out when he had to figure out if a crown was made of solid gold When an object is submerged in water it will displace its volume in water This means that to find the volume of an object it is placed in water Then the volume of the water that is displaced is equal to the volume of the object So when a person is placed in water the volume of the person is equal to the volume of the water that they displace This is useful because there is a formula to find percent fat mass from the density of an object Density is equal to mass volume Finding the mass of a person is easy just weigh them but this is the easiest way to find the volume of a person The density is also called the specific gravity 2 Understand the differences and usefulness of different body composition and anthropometric assessment procedures discussed in the text and class What are the general assumptions used by indirect measures Different procedures exist to measure body composition Among these is the skin fold the bioelectrical impedance BIA underwater weighing explained in question 1 x ray and calculating BMI Direct means that they are taking it at an autopsy Clearly not too practical These are all indirect and they assume that all mass in the body is either muscle or fat they don t take into account water mass bone weight or air volume Tony Berardi 2 Skin folds are the most common and this is based on the fact that most of our fat is subcutaneous meaning that a majority is found at the surface of the body Using this knowledge seven skin fold sites are pinched with caliper and these numbers are plugged into a formula to get percent body fat All the pinches should be made on the right side of the body This method is not that accurate depending on if the tester sucks and can be affected by many things like exercise this will increase the thickness of your skin being dehydrated decrease thickness of the skin and age As you age fat moves to being more visceral so an old person would be calculated as having less fat Then we have the underwater weighing This is the gold standard and yields the best result but it isn t that practical like the skin fold is Fat is less dense than water so the more fat that someone has the less they will sink The BIA is pretty stupid This is a hand held device that sends a current from one hand to the other Fat does not contain electrolytes so it doesn t conduct current as well as lean mass which has electrolytes So the lower the current reaches back to the machine the more fat a person supposedly has As you can probably see a lot of things can affect this If you are dehydrated then you will have more electrolytes in your blood because of less water and will conduct the current faster and your body fat will be underestimated If you are hydrated the opposite will happen and the fat amount will be overestimated If your skin is warm then the current will travel much faster and underestimate it then if your skin is cold the current will travel very slow This had me at 2 ones time Clearly not right X ray will reveal bone mass and you can calculate fat mass from this and BMI is an anthropometric measurement taken from one s weight in kg and height in m 2 It is in the units of kg m 2 This will put someone in ranges of underweight normal overweight and obese 18 5 is underweight 18 5 24 9 is normal 25 29 9 is Tony Berardi 3 overweight and above 30 is obese But this is not the best measurement for fit people as it doesn t take into account muscle which weighs more than fat Another anthropometric is waist circumference girth This is a really good measurement for the amount of fat that is in the abdominal region Fat in this region is bad The two common classes are android and gynoid shape Then you can get fancy with the bodpod a 10 000 machine The machines measures the volume of the machine and then measures the volume with you in it and finds the difference This is fairly accurate yet expensive o So the best one is underwater weighing and waist circumference for anthropometric But underwater weighing is the gold standard for measuring body fat o The norms are around 15 for men and 26 for women 3 What are the body composition differences between males and females Males have less body fat because only 3 is essential whereas 12 is essential in females This is due to the fact that females need fat for their menstrual cycle and all that good stuff Tony Berardi 4 Understand the difference between essential and storage fat and the difference between FFM and LBM Essential fat is what the organs need to function properly This is needed for the bone marrow nervous system for example Storage fat is just that storage This is extra fat you accumulate from your lifestyle It can be subcutaneous right under the skin or visceral surrounding the organs 4 5 How does energy balance and weight loss affect body composition If you consume more kcal than you burn off or metabolism than you will store those kcal as adipose or fat simple The things that determine your metabolism are the thermic effect of food this is the energy that your body uses to actually digest and absorb the food protein has the highest your activity level and your resting metabolism to the highest impact based on your muscle mass A pound of fat is equal to 3500 kcal 6 Understand the potential impact of diet and exercise on obesity e g what are the differences of dieting alone as compared to dieting and exercise combined Exercise is not as effective as cleaning one s diet Exercise is great and all but no matter how much you exercise if your diet sucks you will not lose as much weight Diet is also great by itself but you will not gain lean body mass muscle without exercise Both of these have to be prescribed to have the best effect on obesity The best plan is the exercise 30 min a day four times a week The diet only group will lose weight but not as much as if combined with exercise If you exercise alone you will lose weight and gain lean body mass but you will lose more weight if you combine this with diet but combined you will not gain as much lean muscle Moral of the story Exercise and control your diet to get the best results on weight loss 7 Understand the concept of the energy balance equations Tony …
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