Body Composition Lab

Introduction:
This lab is designed to measure body composition which is the absolute and relative amounts of body constituents. The human body is composed of fat mass and fat-free mass, when conducting this lab we generally discuss about the percentage of the body mass that constitutes as fat. The purpose of this measurement is to recognize the strong relationship between obesity and increased chance of coronary artery disease, type II diabetes, and hypertension. As we grow and age, body composition testing allows us to institute an ideal weight, compose a blooming diet and design a fitness plan that is right for the body. When measuring body composition, there are two categories: direct and indirect. Direct methods include chemical analysis

and dissection which is only plausible on a cadaver. Indirect methods include property or component. Property based methods involve measurement of specific properties such as body volume and component based methods involve established models or regression analysis to establish an equation.

Percent body fat corresponds to the total weight of the body that is fat mass. I hypothesize that the 3 or 4 skinfold sites would increase as the percent body fat from circumference also increases.
Methods:
The primary to calculate body fat is skinfold testing which will require suitable calipers. All measurement must be taken on the right side of the body and the technician must hold the caliper in the right hand and pinch and pull the skin using the thumb and index finger of the left hand. The caliper must be held perpendicular to the fold of the skin, 1 cm away from the thumb and index finger. To get an accurate measurement, read the dial to the nearest 0.5 mm, 1-2 seconds after the grip has been released. A minimum of two recording must be registered. The 3 or 4 skinfold sites are the chest (males), triceps (females), abdomen (males and females), suprailium (females), and thigh (males and females). The chest: a diagonal fold taken half the distance between the anterior axillary line and nipple for men and one-third of the distance from the anterior axillary

line to the nipple for women. The triceps: a vertical fold on the posterior midline of the upper arm with the arm held freely to the side of the body. The abdomen: a vertical fold taken at a lateral distance of approximately 2 cm from the umbilicus. The suprailium: a diagonal fold above the crest of the ilium at the spot where an imaginary line would come down from the anterior axillary line. The thigh: A vertical fold on the anterior aspect of the thigh midway between the hip and knee joint. Body mass index (BMI) was also measured in relation to body composition. This required the measurements of weight in kilograms (kg) and height in meters squared (m2). We can apply a formula to estimate the % body fat based on BMI. Finally we measure body circumferences of the iliac crest by palpating the iliac crest and laying the tape horizontal and across the iliac crest. For abdomen we choose the narrowest point between the iliac crest and ribs and measure. For hips we can lay the measuring tape horizontal across the greater trochanter. The waist to hip ratio can be determined to estimate the health risk associated with BMI. Using the body density found by the body circumference measurement we can calculate % body fat using the Siri equation.

Conclusion:
In conclusion 3 or 4 skinfold sites has a moderate correlation with percent body fat of body circumference.

When plot on a scatter graph, the correlation is +0.66257 indicating that the relation of both factors are parallel. Potential sources of error when measuring body density include: for the 3 or 4 skinfold site, reading the value of the caliper in an incorrect fashion, not allowing for the caliper to completely lock onto the skin before taking a reading, not considering the obstruction of clothing when recording the measurement, not pinching and pulling the skin in the right location, including the muscle associated with the skin before measuring and holding the caliper parallel to the direction of the pulling skin while recording. The common calculation errors can include entering the formula in an incorrect manner while in Microsoft Excel and entering the male skinfold site with female information and also calculating the sum of individual skinfolds incorrectly. For body density relating to body circumference, potential errors can include not measuring weight and height accordingly as they are a requirement in the formula. When examining the relation between % body fat at 3 or 4 skinfold site there was a slight difference in values for all groups. I feel that the more sites available for measurement would give a more accurate value of % body fat will be determined because it will provide you a greater index of change when you measure multiple sites. The relationship

between VAT and health showed no correlation of VAT and BMI whereas 3 or 4 skinfold sites and VAT showed a negative correlation. The values of my percent body fat were similar in different methods and were comparable between techniques of measuring body composition. The amount of weight to gain or lose to reach the weight at the desired % body fat varies because the % body fat we would need to find the body circumference and find out the body density, and then use the Siri equation to get the % body fat. If my goal was to lose weight, my weight and body circumference would be reduced significant to reach a desired % body fat and the opposite would happen if I were to gain weight, my weight and body circumference would increase. Overall, the individual would have to set goals to have a desired % body fat or BMI to maintain a healthy lifestyle.