welcome back our lecture today is looking at body composition so not just what is body composition and how is the body functioning based on the different tissues that we have but also we're going to look at some of the techniques that we use to either measure body composition or estimate body composition so let's take a look at defining body composition and then we'll dive into some of the clinical measures and some of the field measures that we use in exercise physiology and kinesiology so what is body composition if we were to take the body and figure out what is the makeup of the human body we can break it down into different models so really what we want to know is how much fat mass is there and fat Mass being an inactive tissue as compared to fat free mass that you'll see abbreviated very often as FFM so fat free Mass can be considered also synonymous with lean tissue in lean tissue we consider an Ive tissue meaning that it's going to burn energy so think about that that muscle is considered a lean tissue and that means that it's going to burn uh energy throughout the day that's where a lot of our metabolism comes from in addition to organ systems that are inside the body so when we look at the different models of body composition you could break it down into something like a chemical model so a chemical model is where we're looking at how much fat how much protein carbs water and minerals are making up the human body we could do something like an anatomical model where we have adapost tissue which is also just the scientific word for faat there we have muscle organs bone and then what's considered other there most common what we use though is the two component model so the two component model just breaks it down into fat mass and then also fat free Mass so fat remass can be all of the other things that are outside that inactive tissue so muscle bone organ systems and so on you also have a second type of a two component model here known as the binky two component model so the binky 2 component model is very similar to what we were saying is the most common here that we'll talk about but what the binky model does is it breaks the fat Mass into fat and essential fat so you have two different types of fat in the body you have non-essential fat and you have essential fat and we'll see that as we look further into body composition so what's the significance why do we do this one of the reasons that we want to do that is is because it's an indicator of your nutritional status and health status we want to know is there an energy balance in the body so in other words does energy in match the energy out we want to make sure that we're in a balance because if we have more energy in than energy out that means that we're going to end up gaining weight we're going to store that excess amount of energy inside of the body the downside to that is a lot of times over time the body will end up storing it as fat now if we want to go into something like a weight loss then we got to make sure that we have more energy out than energy in and what that does is that creates a negative energy balance when you're in a state of a negative energy balance we can lose weight there so when we talk about the indicator of health status and nutritional status we can see things like obesity which are going to be related very often to things like cardiovascular disease and diabetes we could identify things like anorexia or sarcopenia so sarcopenia remember is the loss of muscle mass which is going to lead to a reduction in your physical function your functional capacity or we could identify things like osteoporosis so osteoporosis is where we're losing bone mineral density and the bone becomes fragile and frail so we're at a high risk of fractures there another uh reason for looking at body composition is to separate the body into to metab metabolically active tissue which is your fat free tissue also known as your lean tissue or lean mass so all of these are used synonymously then we have inactive tissue which is considered your fat Mass so we've done this before when we separate the body into lean tissue into fat mass or fat free mass and fat Mass we can use that to be able to normalize our physiological measures so remember when we've talked about before with BO2 and we take into account body weight in kgs and we use the measure unit of measure of MLS per kg per minute that's what we refer to as relative V2 because it's relative to that person at that point we're taking into account an individualized factor and making it relative to that specific person so that's one of the reasons that we want to look at body composition we could even take it further since V2 is the volume of oxygen being consumed at the level of the active tissue we could normalize V2 to lean mass so we could end up taking say if we had somebody do a V2 test an exercise test on a treadmill and we take them to Max Capacity so we get a true V2 max value we could normalize that to the level of lean mass in the legs because that's the primary active tissue during that exercise when they were running on a treadmill so we could be as specific as possible and that gives us a better ability to normalize the data to be able to categorize that someone into a cardiorespiratory Fitness status and compare individuals from different body types and body sizes and then we can also determine someone's desirable weight we'll see that at the very end of this PowerPoint today a formula that we can use if we know somebody's body fat percentage and their body weight we can figure out how much do they need to weigh or what much do they need to lose to be able to get to a certain body fat percentage that's their goal so different ways of looking at body composition we could do direct measures we don't really see that this very often because if you look at direct measures we're talking about anatomical dissection and a chemical analysis you don't really want somebody walking up to you and say hey let me do an anatomical dissection on you so that's really not a feasible technique for analys or analyzing body composition but it is a direct measure because with anatomical dissection we're actually looking at the tissues of the body so we're directly measuring it there or a chemical analysis being the same way since those aren't always feasible um what we can look at are indirect measures indirect measures mean that we're measuring a certain variable and we're predicting what body composition is based on a relationship between that variable and body composition itself so we're going to spend the lecture today talking about these indirect measures here hydrostatic weighing air displacement plus mography which is also often referred to as bod pod because that's machine or the technique that's used in air displacement we'll talk about dexo which is dual energy x-ray absorb datometry so we have a dexa machine that we use very often to measure body composition which is a uh also noways referred to as the gold standard technique for measuring body composition we could use an MRI we can use field techniques if all of these clinical so up here here these are all kind of clinical techniques of measuring uh body composition but if you don't have access to those then we can use field techniques which is something like a skinfold caliber you measuring the thickness of the subcutaneous fat layer underneath the skin or bioelectrical impedance analysis which is often referred to is Bia so we'll look at each one of these here before we get into the techniques a lot of everything that we know about body composition and being able to use these indirect measures to estimate body composition came from densitometry so densitometry is the measurement of the density of the body so we're calculating a variable down here known as body density which is represented by DB there in parentheses since we know that an object is a mixture of the two components in other words the object object being the body here since the body is a mixture of the two components being fat mass and fat free Mass each one of those tissues have different densities so we see here that the density of fat is 0.9 G per cubic cm whereas density of fat free mass or in other words muscle or lean mass is 1.1 G per cubic cm so we have a different ways to be able to estimate body density by using things like measuring body volume so when we look at the densities of the tissues you've got 0.9 and 1.1 when we talk about water water has a density roughly of uh 1.0 gram per cubic cimer that can change a little bit based on the temperature of the water so if the water temperature goes down we'll see that the density changes a little bit so you may see a density of water be something like 0.9995 76 or whatever it is based on the temperature of the water at that current state but as you can see with these decimal points here that's very close to 1.0 so 1.0 you can see Falls right here in the middle of your range of the density of your tissues so in general what we can say is since the density of fat is less than water .9 here is less than 1.0 then fat is going to end up floating in water whereas fat free mass is going to sink in water because the density of the fat free mass is greater than the density of water at 1.0 so that allows us to be able to do things like measuring your weight underwater and we can determine body volume from that once we get body volume and we measure your body weight now we can determine your body density so when we talk about body density if your body is made up of two types of tissues you have fat mass and fat free Mass fat Mass has a density of 0.9 fat free Mass has a density of 1.1 your body density total density of the body has to fall somewhere between these two values so anytime you're ever calculating body density you should always look for a number that's 1.0 something so that could be 1.05 1.03 1.87 whatever it is but it has to fall between 0.9 and 1.1 so that's just kind of a just a trick to think about when you're calculating body densities in the future to determine body fat percentage that DB variable body density should be 1.0 something now the way that we can one of the ways we can measure body volume to get body density is to determine underwater weight so this uww stands for underwater weight and the way that we can measure your weight underwater is through a technique known as hydrostatic weight so hydrostatic weighing uses a big tank something like you could think of it like a a small pool or an oversized hot tub or whatever it is you want to think of but we have to have enough room to completely submerge the body underwater and we're going to measure the weight of the body so that what you're sitting in apparatus whether you're sitting in this chair that goes underwater or you're laying on a little table that sinks Down Under the surface of the water it's all attached to a scale so once you get on that and submerge the body underwat that displaces water within the tank so based on the level of water displacement we can determine what the weight of the body is underwater because of something right here that says the volume of an object is equal to the volume of the displaced fluid so if you answer this question right here if you've ever had a physics class before you've learned this before this is what's known as AR aredes principle so Archimedes principle says the buoyant force is equal to the weight of the displaced water so here's an example right here if you have this weight and everything's attached to the scale up here and above water it's weighing seven pounds as you can see right there you drop the weight down in the water you'll notice that the water level is going to rise because it's going to displace water in the tank so as the water rises it exits out of here spills over into the bowl and if we measure the amount of water that's in that bowl and be equivalent of 3 lbs that means that our underwater weight above uh water level was seven so s minus your 3 PB means that your underwater weight here is 4 pounds so we can determine the actual volume of the body from that so we get uh underwater weight here we take your body mass in other words your body weight minus your underwater weight divided by the density of water so what we need to do is we need to measure the temperature of the water get the exact density again it may be 0.9976 53 or whatever it is is going to be very close to 1.0 but we plug that in the formula there and then we want to estimate what your residual lung volume is as you have somebody go down underwat you're you're to instruct them to Exhale as much air out of their lungs as they can so typically an easy way to do that is if they're sitting in a chair and they go down into the tank as they go down underneath the water you want to tell them to Exhale I want you to blow as many bubbles in the water as you can and Bend forward as you're doing that because as you bend forward you get the extra squeezing of the thoracic cavity there to try and force because of the pressure inside here to Force air out and you get the assistance of gravity there we don't want to have a lot of air left in the lungs when you go under waterer because if there's air left in the lungs when you go underwater the air in the lungs is going to cause you to float what did we also say floats in water fat floats in water so if your uh air is left in the lungs and that's causing you to float a little bit more your underwater weight's going to be a little bit higher so that's going to end up causing uh miscalculation in your body fat percentage because it's estimating that the fat is what's making you float and then we have correction factors to estimate the level of air uh that's left in the GI track so once you get body density or you get body volume you can calculate the body density and then body density you're going to plug into this equation down here which is known as the Siri equation so we're going to take 495 divided by your body density minus 450 and that gives us a body fat percentage estimation this is the most common formula that's used to estimate body fat percentage in the general population we have other population specific equations that may be used for athletes or they may be used for the female population or uh the youth and Adolescent or whatever different types of populations you may be working with specifically but from the general population the Siri equation is the most common so here's an example right here comparing these two individuals you have Jack and Dave here both of uh these individuals have the same height you can see that they're both 188 CM or 74 in they both have the same weight at 205 lbs but look at get the difference in the body type so we can see definitely there's a difference in the body type this one over here is a little more lean so when they go underwater since muscle sinks in water the individual with more lean mass is going to have a higher underwater weight as compared to the individual with more fat Mass because fat is going to float and keep them closer to the surface of the water so what that does is that changes their body volume calculation and you can see here body density where we've taken body weight or body mass divided by uh body whoops body volume is where we get body density so body density here of Jack on the left side the lean guy is 1.75 whereas the body density of the individual on the right Dave here it has a little more fat Mass is 1.57 so you can see what I was saying earlier that it body density is always going to be 1.0 something now you plug that into the Siri equation using their body weight and their body density and we can see that Jack has an estimated body fat percentage of 10.5 whereas Dave has an estimated body fat percentage of 18.4% so if we were just looking at height and weight weight up here we would say that they were equivalent to one another but we can see that the composition of the body is pretty significantly different between the two so 10 a half% versus 18.4% puts them in completely different categories of weight status now to calculate how much fat weight there is what you can do is we're going to take their body weight so we just do this example here you take body weight of 205 pounds not equals there and multiply that by the body fat percentage of 10.5% you have to express that in decimal form so that'd be 0.105 and that's going to come out to a contribution of 21.4 so what that means is out of uh Jack body weight of 205 lb here two uh 21.4 pound of that 205 is fat Mass so now if I want to know what's their lean mass how much of that body weight is fat free weight then I'm going to end up taking the 205 minus the 21.4 and that gives me 183.2 183.0 pounds of Jack's total 205 pounds is lean mass so we can determine what the actual body composition is and the weight of that contribution of that mass inside the body now you can see if they want to drop if Jack wants to drop to just 10% body fat he only has to lose just a very small amount of weight of roughly 0.8 pounds where if Dave wants to get to 10% body fat he's got to lose about 19.1 pounds to get down to there and like I said we'll see a formula on that's calculated at the very end of this PowerPoint so here's a picture of what hydrostatic weighing looks like so it's a tank this is a chair that you have somebody sitting in so it's made out of PVC pipe it's attached to the scale up here and what you do is you have somebody sit down in the chair and once they get in the water you want them to Pat Uh the body down because you're going to have little surface bubbles on the skin we want to get rid of all Bubbles and anything that can make you float you're going to have them dunk their head in the water and pat their hair down to get all the air bubbles out of their hair now once they're completely ready for the test we're going to have them sit in the chair put their arms around the poles right here next to their side and then they lean forward in the chair as they Lean Forward exhale as much air as you can and then go down all the way to completely submerge the body under the water if the top of the head is sticking up above the surface of the water and we have to redo it because that's not underwater so we don't get a true underwater weight then so once the body is completely submerged underwater it only takes about two to three seconds to get a measurement on the scale up there and whoever your uh practitioner is they'll knock on the side of the tank and that person inside the tank underwater can hear that and they come up that's your sign to come up out of the water that's telling you you have your underwater weight measured you can come up now so it's a very useful technique this used to be the gold standard of measuring body composition now we have techniques like the dexa that we'll see in just a minute but with hydrostatic weighing there's sources of error in everything um that you use to estimate something if it's an indirect technique of measuring something there's always going to be a source of air so there's a possibility that there's variation in people and how much what's the percentage of min mineral and water and protein and all of that in their fat-free mass and in their fat mass and everything else bone mineral density is going to vary a little bit um not as accurate for children in using this technique but we do know that with females there's correction factors and with athletes there's correction factors there's even population specific formulas that we can use there can be issues with residual volume so like we said earlier somebody doesn't exhale as much as they can and there's too much air left in the lungs which is going to cause them to float fat also floats so the formula can't differentiate between those two this one right here is the big one is fear of being underwater when somebody's inside this tank and they go down underneath the surface of the water every time they move this Needle on the scale right here is going to bounce it's going to jump a little bit so once they go underwater we trying to explain to them to be as still as possible so that that Needle on the scale doesn't move very much and bounce around we have digital scales that we use as well but again if somebody's moving underwater the number on the digital scale is going to uh adjust to that as well accuracy is pretty good it's plus or minus 1.5 up to 4% but we're pretty accurate with hydrostatic waying once you get used to the technique I encourage you to um click this link right here so if you have the PowerPoint pulled up later on you can hold down control on your keyboard and then click that link and it'll take you directly to a YouTube video very short video of just showing you a hydrostatic weighing uh measurement for body composition now this is another technique right here known as air displacement plus mography so this is often referred to like we said earlier as bod pod so this is a bod right here looks like a little Space Capsule that you have somebody sit in and what it does it's very similar to hydrostatic weighing but instead of measuring water displacement now we're going to measure air displacement so here's a video right here that you can follow hold the control button on your uh keyboard and click that link right there very short video of a bod pod measurement but very briefly what this does is you have somebody you're going to calibrate this uh capsule right here so you can see right here inside the capsule there's a little cylinder so that cylinder is what we use to calibrate the bod pod machine so you place that cylinder in there it's a set known volume and it calibrates and creates a vacuum inside that little capsule now once we're ready for the test we can take that uh cylinder out we have somebody go inside the capsule there's a little bench seat in there and they sit down in there um and they have to be as still completely still as possible and it's going to measure the displacement of the air inside the capsule now so a couple of precautions with this is one if somebody has a lot of hair on their head or hair on their body we have to cover that because believe it or not just the hair on your arms can displace air inside the capsule and that's going to throw off your measurement for body composition so you can use things like dry fit clothing or the tight tight fit clothing um that compresses everything we can use a swim cap for the head and stuff like that to be able to keep everything compressed so we're strictly measuring the uh volume of the body and the displacement of the air that it causes sources of air uh air here uh what we said with hydrostatic weighing there's variation in the percentage of protein mineral and protein bone density is going to vary residual lung volume this is the big one here is excess clothes or body hair that causes a displacement of air inside the capsule another one that's not listed here is movement so if you have somebody that gets inside the capsule one of the major concerns here is somebody that suffers from claustrophobia because the capsule is about the size of shoulder width for a male so when you're sitting in there this capsule comes right around and it closes right here in front of your face so you could imagine that claustrophobia might be an issue when you put somebody in that capsule and it seals and it creates a vacuum because of that people move a little bit when you move that displaces the air around you and that's going to throw off your measurement accuracy is right around a plus or minus of 3% with this technique so although there's sources of erir is still a very very accurate measurement that gets us to dexa so dexa here de you may see it written as dexa or dxa so both of those are acceptable abbreviations for dexa which stands for the Dual energy x-ray absorbit ometry so what this does is we're measuring body composition by using x-rays so the x-rays are very very low energy x-rays so much lower than if you were to go to a clinic or a hospital and have an X-ray done of the body these x-ray uh signals are much lower than that so we don't really have any concern of radiation or anything like that but what we end up doing as you can see this is a dexa machine we have one of these on our floor in kinesiology uh in nutrition and what we do is you have somebody as you can see they're laying on this table right here this arm right here scans back and forth from head to toe over the body takes anywhere from six to eight minutes to do a scan and it gives us a regional distribution so it'll start all the way on one side of the body and scans and it moves over and scans moves over scans and it goes all the way across the great benefit of dexo is we get a measurement of body composition of the right arm the left arm the right leg the left leg the head neck and the trunk so we can compare the different regions of the body in their body composition the other major benefit is we get a three component model measure so not only do we get fat mass and fat free Mass but we also get a measure of bone mineral density from this so dexa can break everything down into three components instead of just the two components the energy from the x-rays are absorbed at different levels when we look at the dexa so fat mass and lean mass and the bone absorb those uh x-ray energy levels at different levels and it shows up in a picture is different we'll see a picture in just a second but what that does is that allows us to differentiate where the lean mass is where the fat mass is and then the bone is going to Glow really bright white so you can see that right here so we can see that everything is glowing different so we can see the bone here bones of the hips and the legs and all of that stuff as we're coming down your lean mass lean mass are these areas that I'm just drawing little dots on so right here on the calf on the legs the thighs here um that are glowing a little bit more of that bright white but if you look right here around the hips trying to outline this and I can't draw straight lines but you see this little faint area right here around the hips in this region so I'm just going to kind of this is all through here so this right here is lean tissue so in other words that's muscle but you see right around the outside of the body we have this little lightly shaded area that lightly shaded area is fat Mass so what this does and you can see it up here this circled in the blue here right here around the outside of the arm I'm going to erase that so maybe you can see it a little bit better that's fat mass and what this does it allows us to be able to identify where are you carrying more of the subcutaneous fat so an excellent technique uh to be able to look at body composition here very accurate plus or minus 3% and what we considered the new age gold standard for body composition maybe you've heard of something called BMI so BMI stands for body mass index and we'll talk about BMI in just a minute but it's using to calculate BMI you use somebody's height and their weight and you divide them and you get BMI this is an example here of two individuals that have the same BMI if we were just using height and weight they'd be classified as the same body type body size and the same uh weight status category both of these being in the overweight um or obese category being above 30 here so what we end up seeing when we look at body composition is hopefully you can tell I know it's kind of hard to see on this picture here but hopefully you can tell this individual on the left side is much more lean so look at the level of the muscle mass in the arms and in the legs all of that tissue that's surrounding the bone all of that is muscle but if you look at this look how there's a difference in the um the tint of the shading so the individual on the right is uh much less lean and then also look at the shading of the the muscle tissu so let's talk about the thighs right here so you can see the shading of the muscle mass here and the shading of the muscle mass here the individual on the left is much more lean and that tissue is more dense so it's showing up as a lot a little bit darker gray around the bone whereas this is a little bit more faint and then you can see a little light outline all through here around the body and that is all subcutaneous fat you can see it here on the inner thighs just drawing on the outside of that line there you can see all of that you can see it up here on the sh whoops it's telling you I can't draw straight line out here on the shoulders so this is the edge of the lean mass right here so this faint area up here is all fat so that's all subcutaneous fat underneath the Skin So now by looking at body composition we definitely know that these two individuals are not equivalent on their weight status so although based on BMI this individual would be classified as obese we know that they're not obese that body weight is coming from a lot of lean TI you a lot of muscle mass within the body so here's an example of a dexa print out so like we said you get Regional distributions here you get left arm right arm trunk right leg left leg the head subtotals what's your body type is it Android or gynoid body type and then we get distribution charts here so based on your age and your fat uh percentage where do you fall in comparison to normative data so this individual right here with a body composition total body fat percentage of 22 is falling within the normal range on their body weight or their body fat percentage and then we have adapost indices and lean mass indices and then we'll have another table on a different page that represents all your bone measures so bone mineral content bone mineral density and so on those were all clinical techniques so if we flip back to all of these right here and talk about the hydrostatic weighing so hydrostatic weighing would be considered a clinical technique air displacement pomography or the bod bod pod is clinical and dexa is clinical the D these are all great techniques very accurate but they have downsides one of the downsides is You' have to you're stuck to a lab or a clinic you can't pick those pieces of equipment up and just move them wherever you want them the other downside is they are very very expensive so you getting a hold of those pieces of equipment can cost a lot of money and it also cost money to have to do those scans and have them done so uh to offset that we have other techniques that are known as our field measures which are much cheaper we can go out in the field we can go to local gyms we can go to schools we can do these wherever we want to and we're not limited to being in a CL in a lab setting so with field measures one of the number one uh techniques in a field measure for body composition is the skinfold method so skinfold method uses a little caliper we'll see a picture in just a second but it uses a little caliper it looks like a little pincher and it's got two little prongs on it and what you're doing is you're going to take a little fold in the Skin So if I take my arm and pinch the skin right here I get a little bitty fold I don't want to get get the tissue underneath I just want that skin right there so when I take that little fold then I can place the skin caliper on there and it gives me a measurement of the thickness of that fold based on the thickness of different SES around the body that we'll look at we add all of those up and we get something called sum of skin fold so the reason that we use that is because we uh there's a relationship between subcut fat and total body fat so it's estimated about one3 of all fat in the body is located subcutaneous so underneath the surface of the skin and because of that since we know that that relationship is present we can use subcutaneous fat to estimate total body fat so we're going to go around the body and we'll talk about these sites in just a minute but we're going to measure the thickness of the subcutaneous path these little folds that we take at multiple sites and we estimate total body from that so we get body density calculation and then we plug that body density um so we use the body density in the Siri equation that we saw earlier and we estimate body fat percentage there's different techniques so you could use a three sight technique or a seven TI sight technique seven sight obviously because we're measuring uh more sites is going to be more accurate in the representation of our body density calculation so here's the seven sites that we use on adults so we have the chest the abdomen the thigh the tricep the suprailiac the mid axillary and the subscapular and then we can add the calf and the bicep in when we're doing skin fold technique on children so let's look at each one of these sites specifically because they have anatomical identified locations where you have to measure these at the specific spot so one thing you'll notice as we're talking about each one of these sites is there's going to be a direction of the fold the direction of the fold is going to be one of these two it's always going to be diagonal or vertical so when we have the other direction you're never going to have a horizontal B so make sure you take note of that it's always either going to be diagonal or vertical when we talk about vertical don't think of that as your fingers being vertical and pinching this way your fingers are like this and when you pinch PCH the fold of the skin is vertical so if I were to pinch my skin like this the fold is vertical it's up and down here and then diagonal you can see on the chest is going to be at an angle you can always think that the direction of the fold is going to follow the underlying structure of the body so on the chest here we have the pectoralis major muscle that's attaching right here and it's kind of going Di diagonal back up here towards your shoulder your fibers of that muscle are looking like that on the abdomin we have the ABS so you've got the rectus abdominis muscle and these are going to be vertical fibers there so you're really going to be following the underlying structure if you want to think of it that way that's an easy way to remember the direction of the fold there all right so with the chest the chest is a diagonal fold that's directed from the shoulder down towards the nipple and for men it's going to be the midpoint between the armpit and the nipple so we're going to go halfway from right here at the crease of the armpit to the nipple and we're going to get a fold there a diagonal fold at that sight for females it's going to be onethird of that distance closer back towards the shoulder so fold of the armpit and the nipple we're going to go oneir of the distance and take our diagonal fold right there we'll talk about technique of doing your folds and using the skin calipers in just a minute with abdomen we're going 2 cm to the right of the umbilicus so to the right of the belly button here and we're taking a vertical fold right there with the thigh yeah with the thigh we're going to go halfway between the hip and the knee so the hip and the knee here we're going to go halfway and we're going to take a vertical fold right on the front of the the thigh so if this is my thigh right here my hip and my knee I'm going to go right here on the front over the belly of the muscle of my quads and take a fold there with the tricep we're going to go halfway between the acroman or the shoulder and the elbow and we're going to take a vertical fold on the back side of the arm this is one that we always have to correct people on on where is the appropriate location to take your fold because a lot of times people think that the tricep is right here why is that because when you go to the gym or you do exercise and all that stuff or if you've ever tried to flex your muscles in the mirror you flex your tricep that's where you see it is right there we always think of that as a little horseshoe muscle but your actual tricep is located back here on the back side of the arm so that's where I want to take my fold is back here where it's real tender that's the one where you take your fold and people might Flinch a little bit think thinking you're going to pinch them and hurt them but we don't want to pinch hard enough where it causes any pain it's just a little bit tender right there so we're going to go halfway between the shoulder and the elbow and get that vertical fold right on the back side of the arm last one's here we've got Supra iliac so imagine your iliac crest is coming down like that so we're going to go just above the iliac crest and take a diagonal fold following that line on the right side of the body mid axillary so don't get that confused with auxilary we see it written like that all the time we don't want that we want axillary so mid axillary means your side so what you're going to do is easy way to find this is have somebody lift their arm up a little bit find the middle of their armpit and come right down the side of the body I want to go in line with the zpid processor right here at the base of the sternum and then over here to the side the midline of the body and we're going to take a vertical fold right there and then the last one is the subscapular so meaning just below the scapula so your scapula sitting on your back like this you have your two scapula if I can draw it I don't know if I can draw it let's see you have your two that's horrible you have your two scapula sitting on your back here with your shoulders coming down so what I want to do is I want to find the inferior angle of the scapula the easiest way to do this this is what I try and teach everybody that's going to use Skin calipers to do is to have your participant put their arm behind their back when they put their arm behind their back it causes their scapula to protract a little bit and that inferior angle will poke up you'll end up seeing a little raised area bump in the skin right there so you can put your finger right there on that you don't even have to look at it to see it you can feel the inferior angle sticking up a little bit put your finger on it and then tell them to put their arm back down by their side once they put their arm back down by their side now I know where the inferior angle is so if my scapula again my scapula is sitting on my back I know where the inferior angle is I want to take a measurement right here subscapular below the scap scapula just below the inferior angle so I'm going to take a diagonal fold because the scapula sit on your back at a diagonal angle like this so I want to take a diagonal fold that follows this medial border of the scapula so I'm taking a fold right here that looks like that now when we talk about technique of doing skin fold measurements so one I want first thing I want to make sure that my participant has their shoes off think about why if I'm taking measurements of the leg and all of this stuff why would I want them to take their shoes off Well everybody's shoes are going to have different heel Heights on them so you may have somebody or the same person comes in on day one and they're wearing Crocs or flipflops that are flat footed and then day two that they come in or the next time that you see them and they're wearing a tennis shoe that has an elevated heel or they're wearing something like cowboy boots or anything like that that keeps their heel elevated like that when the heels elevated that causes flexion of the musculature of the legs when the muscles are flexed it tightens the skin so now when I do my skin fold and I try and measure the thickness of that fold there it's going to be different because the elasticity of the skin is changed based on the contraction state of the muscle underneath so it's just a way to standardize everything to make sure that every time I measure skin fold on that person or with anybody I'm doing it the same way this is a big one right here is all measurements are taken on the right side of the body so that has nothing to do with right-handed versus left-handed people it doesn't mean right-handed people are more dominant than left-handed people or anything like that we just standardize it to the right side of the body so that way if you come to my clinic and I measure your skinfold thickness and then you go to somebody else's clinic or a gym or something like that and they measure your skin fold thickness we're measuring the same sight because believe it or not my body composition from my right arm to my left arm can be different so I can have a greater lean mass in my right arm than I can in my left arm and if we're measuring different arms at different sights then it's not going to be accurate in our comparison so all measurements are taken on the right side of the body now once you locate each one of your uh skin fold sites what I tell people to do is take a little pin or a dry erase marker or something and just Mark just do a little dot on the site that you're going to measure so for the chest we're going halfway here for males between the shoulder and the nipple so we're going to get our diagonal fold right there I'm going to draw just a little bitty dot because I have to take multiple measurements at each site since I'm taking multi multiple measurements at each site I want to make sure that I'm coming back to the exact same spot and taking the same measurement because I don't measure the same spot two or three times in a row I'm going to start at one I'm going to go through all seven sites and then I'm going to come back and I'm going to go through all seven sites again that allows me to let the skin go back to normal with its elasticity if I take a skin fold here and I pinch the skin as even though I'm only doing it for one two or three seconds uh the elasticity of the skin changes and I disrupt the connective tissue there so I want to make sure that I give it enough time to rest and recover go through all seven SES and come back to that same sight to make sure that the elasticity of the skin has returned all right so I'm going to grasp my fold between the thumb and the forefinger and I'm going to just pinch it hold the skin just a little bit a big recommendation and going back to these P pictures this is a pet peeve and a bad technique to use of what you see in the pictures here you don't want to pinch the skin with the pads of the fingers so this part of your finger right here where your fingerprint is and that's what you see uh is happening here if you pinch with the pads of the finger you're likely to get a larger fold because now I'm actually pulling away all the underlying tissue Under the Skin So it's going to make my fold thicker and that's going to be an inaccurate measure what I tell people to do is think like you have a claw and I want to pinch with the points of the finger so when I get my fold here you can maybe see the difference on camera I don't know if you can but I'm trying to show you you can it's a much greater difference in the thickness of this fold of just just grabbing with the points of my fingers versus grabbing with the pads of my fingers and getting all of that underlying tissue so drastic differences in the estimation of body fat percentages just coming from a simple technique correction like that all right so we're going to place the calipers once you get your pinch on the skin I get my fold now this is not a skin fold site I'm just using this because it's easy to show on the camera but I get my skin fold right here with my other hand I'm going to take my calipers and just place the calipers on there the calipers if you look at them have these little prongs and the prongs are spring loaded so there's a spring right here once you open the calipers up and then place them on the fold you just let go of the trigger and the caliper is pinch down on the skin very very very light pinch you would won't even know that anything's happening there so it's not like they're squeezing down really hard but what it does is it has a gauge on here so this right here is your gauge on the other side is a reading that gives you a thickness in millimeters so we're going to take our measurement there all right so we place the calipers about half an inch from your fingers where you're holding your fold make sure that when you put your calipers on there you still want to keep your fingers on here and hold the fold together because if I let go of it you see how the fold Falls away from my skin the calipers even though they're spring loaded aren't strong enough to hold that skin fold there so I got to keep my fingers pinching that fold together as I take my measurement read your measurement on the gauge within one to two seconds all the measures are going to be in millimeters and we take two to three measures at each site we rotate through all seven SES before we take the second or the third measure at a given site if two measures are more than 2 to 3 millim apart then we take a third measurement because I'm going to end up taking the average of my measures that are closer together so for instance let's say we did the bicep or let's say the tricep so we took a tricep measure uh measure number one was 6 millim measure number two was uh let's say 10 mm that's 4 mm there's difference between two measures at that site so I'm going to have to do a third one so I come back and do my third one and my third one was say 7 and2 millim so because uh this one is outside that acceptable range of two to three millimeters I throw that one out and I'm going to take my two measures that are closest to each other and I'm going to average them together so now I have an average measure for my tricep and I'll have an average measure for all seven sites once I have the average for all seven sites I'm going to add those averages up and that's what we call sum of skinfold so the sum of skinfold is equal to the average of all seven sites added up so like we said we'll have tricep we'll have subsc we'll have Supra iliac let's just say Supra there we'll have the abdomen I can't spell abdomen we have the thigh and so on uh we move through all of these we have mid axillary and we'll have chest we'll take the two measures from each one of those sites that are closest to each other and get an average average of tricep average of subscap super iliac abdomen thigh mid axillary and chest add each one of those up and that's your sum of skin fold there so very accurate technique as long as you're measuring the same sight and it takes practice there's going to be a difference in your measurement in the value of millimeters between testers that's just given so if I measure you or if you're in a gym and somebody measures your skin fold um using the skin calipers then you want to make sure you try and go back to that same person that's going to be your most accurate method for getting body fat percentage we can use inator uh reliability here but you know it's always going to be best if you use the same person doing the test um but as long as we're following our procedures and doing all of our measures on the right side of the body at the exact anatomical location where it's supposed to be it's still going to be pretty ACC accurate so we have accuracy about plus or minus 3 to 4% there all right these are all just your skin fold site so this is a table um that you'll see in a textbook from ACSM on exercise testing and prescription and the appropriate description of all your skinfold sites and then the procedures down here here's your skinfold equation so this is body density equation for males using the seven site technique you don't have to know these equations or memorize these these will be in a textbook if you ever use them in the future you could print it out or whatever you need but you'll notice the values that you have to plug into the formula so you've got 1.12 minus this long value multiplied by your sum of the seven skinfolds plus this value multiplied by sum of skinfold squared minus this value multiplied by your age and years there so that gives you body density and then you can plug your body density into the Siri equation and get body fat percentage here's a three sight formula for males another one for males seven sight formula for females and three sight for females there so a lot of different techniques to get body density here now Fitness categories based on your body fat percentage no matter whatever technique you use whether it's dexa or B po or um something like your skin calipers or anything like that you're going to get body fat percentage here's your Fitness categories based on body composition and body fat percentage so for females age 20 to 29 we see that good category would be between somewhere around 17 and a half to almost 20% body fat what do you notice as you get older the acceptable range of body fat percentage as you age goes up there's reason for that because that's just going to happen as you get older that's an age there's an age Associated loss of muscle mass so we have redistributions of body composition hormonal changes and all of these things happen as you get older so our acceptable body fat percentage is going to go up as you age same thing that you see with males here males the acceptable range right here in the good category for Fitness is a a little bit lower as compared to females remember females was about 17 a half to 20% whereas males males don't carry as much body fat percentage or body fat in the body when it comes to body composition so the acceptable range is a little bit lower but again as you age the acceptable range goes up and this last technique here is bioelectrical impedance analysis so bioelectrical impedance analysis uses uh a uh electrical signal to go through the body because different tissues in the body will conduct electricity differently we can use that the speed of that electrical transmission to estimate what body composition is so it says here tissues that contain a high level of water things like blood and muscle are highly conductive to electricity so when you have a very quick flow of electricity going for this is called a hand to hand and Bia so you hold on to it like a steering wheel you press the start button sends a signal from my right hand through my body to my left hand it's going to measure the speed of that conductivity of that signal um the faster it transmits through the body the lower the fat Mass fat bone and Air Field spaces do not conduct electricity very well so when the current moves very slowly that represents a high fat Mass M now this test is one that can be drastically altered based on different pre-test procedures and if they're followed or not so if you have somebody that say they went and did a strenuous exercise session and they created a lot of sweat because they were exercising at a high intensity the muscle tissue at that point and the blood is going to be dehydrated so remember water in those tissues is what's conducting the electrical AC ity so when you dehydrate the body you don't have as much body water content in there so that's going to slow the speed of the conduct conduction of the electric electricity from hand to hand or foot to foot it's going to slow it down so since that speed is slower that's going to predict that body fat percentage is higher you could also have somebody that maybe they drank a lot of coffee before they came in coffee works like a diuretic he going to De dehydrate the body as well maybe had somebody that drank a bunch of Gatorade and water before they came in so they're really hydrated now you're going to speed up the electrical activity and it's going to predict that body fat percentage is lower because the speed of the conductivity is quick all right body mass index real quick on body mass index one thing about BMI is There's no distinction between overweight versus over fat so you have BMI categories that will see right here where BMI less than 18.5 is considered underweight normal weight is 18.5 to 24.9 overweight is 25 to 29.9 and then obesity is classified as anything greater than 30 but you have different classifications of OBC you have class one class two and class three here and they're Associated bmis that go with those classes this right here here I encourage you to know your BMI categories and their classifications but when we go back and we talk about BMI you have an overweight category with BMI but that doesn't mean that it's over fat the reason for that is because the only thing BMI uses is your body weight in kgs and your height in meters squared so you take body weight and kgs divided by height and meter squared that gives you a body mass index so we're not getting a body composition so big thing to remember not a body composition measure this is simply a body mass measure here so however with BMI a high BMI has an increased risk of mortality uh there's very little data of trying to make a relationship between body mass index and body composition but we do know that body mass index or BMI Still Remains the number one predictor of mortality so you can see here as body mass index is increasing from left to right we'll see that the slope of the line is increasing as well which is representing mortality ratio s the risk of mortality goes up with an increase in BMI here now why is BMI still the number one predictor of uh mortality risk the reason for that is because every time you go to a doctor or you go somewhere they're always going to take your height and your weight and what they do is they plug that height and their weight into the uh software the medical record system and it automatically calculates BMI for so BMI now is logged into the medical record how many times have you been to a doctor or a clinic or anything like that they say come on back and we're going to go back here and do a dexa scan before we take you to the room or we're going to jump in the hydrostatic tank or we're going to do skinfold measures before we go into the assessment room you just don't see that so BMI is readily available as a variable and that's why it Remains the number one predictor of mortality here's the reason why we don't want to use BMI and try and make an association with body composition so these two males are same age same height same weight which means that their BMI is the same at 23.5 that puts them in the normal weight category but look at total body fat percentage this one right here is 29.6 whereas this one is 18.5 so some completely different body compositions although BMI is the same so we have to make sure that we're not confusing BMI with body composition now this is a technique that's used in becoming more common as waste to hip ratio so waste a hip ratio is a very good indicator of cardiovascular disease because what we're doing is we're taking a circumference measure around the waist and a circumference measure around the hip and we're getting a ratio here since it's a ratio there's no units of measure as long as you make sure that if I measure my waist in centimeters I need to make sure I measure my hips and centimeters as well so as long as you're consistent then it's a very accurate uh me measurement the reason that this is a good indicator of the risk of cardiovascular disease is because CBD is highly related to Central adiposity so Central osity is how much uh atopos tissue or fat mass or you carrying around your central region in other words your belly so in your abdomen the higher the the uh fat Mass around the abdomen the greater the risk of cardiovascular disease so what we do with this technique is it's a very good technique for the morbidly obese individuals so the class 2 class 3 obesity individuals it's a good measurement to use here and it's a very useful measurement for looking at Weight Loss um or hypertrophy or atrophy of muscle or anything like that so when we talk about our waist to hip circumference ratios for the normal ranges for males we want to see it as close to 0.8 as we can get it so you can see here that the low risk categories for this age range for about college age males is we want it to be close to 0.8 it's a little bit higher for an acceptable range as we get older very high risk when you get up here close to a one ratio a one ratio means that it's a Ono one circumference that means that if I take my waist and divide that by my hip and I get a one that means that they were equal to each other so I had maybe a a 40 divided 40 cmers divided by 40 C or 40 in divided by 40 in whatever the unit of measure is so it's a one: one ratio there with females we actually want to see the uh waist to hip ratio a little bit lower we want to see it as close to 0.7 as we can get it so a little bit lower and the reason for that is because with females females generally have wider hips so the circumference of the hips is going to be larger if we're taking waist and dividing it by hip if you have a larger number on the bottom right there then that's going to create a lower ratio value so hopefully that makes sense there and why females the range for Waste to hip ratio is a little bit lower closer to 0.7 there so here's your chart of your anatomical descriptions of the sights for the hips I want the hip measurement to be taken um with the feet together at a horizontal measures taken around the maximal circumference of the buttocks so what I'm going to do is I'm to have you stand with your feet either together or pretty close together and I'm going to take a circumference right around the middle of the butt and we're going to get that measure and then we're going to take our waist measurement waist measurement is going to be another horizontal measure meaning that it's around the body so a horizontal measure at the narrowest part of the Torso which is usually just above the belly button and below the zpo process so I'm going to go right here just above the belly button I know you can't see it on the screen here but right above the belly button and take a me circumference measure around the body and then I'm going to take my waist measurement divided by my hip measurement and I get that ratio there all right this is our very last thing to talk about is that equation of how do we get um what our desired body weight is supposed to be if we want to get to a certain body fat percentage so whatever technique you use measure bod pod dexa hydrostatic weigh um Bia whatever it was that gave you a body fat percentage if you know your body fat percentage and your body weight we can determine what you need to weigh if you want to get to a different body fat percentage here so the way that you do that is you take your body weight minus your current percent fat times your current body weight and that's going to be divided by your desired percent fat or one minus your desired percent fat so let's do this example right here so I measured somebody's body composition they had 32% body fat they currently weigh 230 pounds so I'm going to have 230 pounds minus my current body fat percentage remember percentages are always in decimal form so 32% times my current body weight divided by 1 minus my goal my desired body fat percentage of 25% so 0.25 all right so I have my current body fat percentage and my current body weight so 230 let's just move down here 230 minus do this math right here in the parentheses I've got 73.6 over 1 - 0.25 is going to give me 0.75 all right so now let's do it a little bit further 230 let's see 230 minus the 73.6 gives me 15640 75 0.75 a calculator down here if you're wondering what I'm looking at 0.75 is going to give me a desired body weight of 28.5 pounds so for me to go from 32% down to 25% I have to drop my body weight from 230 to lose to get to this desired body fat percentage I would take my current body weight of 230 PBS minus their gold body weight of 28.5 pounds and that tells me I need to lose 21.5 pounds write it over here need to lose 21.5 pounds to get to my desired body F percentage of 25% so just one of the reasons why we calculate body composition is to figure out somebody's goal if you're writing exercise prescriptions this can be an excellent technique to motivate somebody to exercise and reduce the barriers to exercise and their adherence to a program so one thing I want you to do after you've gone through all of this material is I just want you to dive into to the internet and just research this question right here there's a something out there called metabolic syndrome so I want you to look up what is metabolic syndrome how is it identified so there's different criteria that we use to identify you have a set to have a certain number of the criteria to diagnose uh metabolic syndrome and can it be treated quote unquote if it can be treated how so so just think about these questions these are just some kind of practical questions to think about if you're going to go out into the working field the things that you need to be familiar with that's existing out in our field so take a look at these questions you don't have to turn this in for a grade or anything I just want you to do this on your own time at some point and just look up some information related to body composition that's all we've got for this lecture so if you have any questions feel free to send those to me post them to Canvas under the discussion tab um and I'll be happy to answer those as soon as possible