Sport

I. Purpose
The purpose of this activity is to become familiar with the different methods of determining the percentage of body fat, classifying bodyweight and assessing disease risk associated with obesity based on bodyweight and percentage of body fat.

II. Results
See Body Composition data sheet and Hydrostatic weigh worksheet.
   
b.   Of all the methods used in the determination of percent body fat values, I feel that the bioelectrical impedance analysis (BIA) gave the most accurate estimation of body composition since it uses several factors in determining percent body fat which is the percentage of bodyweight that consists of fat. It considers the skin fold technique which is based on the theory that half of the total body fat is located in the subcutaneous tissues of the skin and that the sites selected for measurement are representative of the overall subcutaneous fat. Another factor used in bioelectrical impedance analysis is the measure of the body resistance to low-level electrical current which allows for the calculation of percent body fat based on the poor electrical conductivity of fat compared to lean tissue. Although this method has some limitations, particularly the effect of hydration level of the body and the ambient temperature, I feel that the variations in the readings due to these factors are not significant and that BIA is still more accurate than the other methods
     
c. Based on the most accurate measurement that I consider for the entire activity, I fall in the obese category. Considering my diet, activity and lifestyle, I think that this classification is fairly accurate since I am not very watchful of my diet and do not engage in a lot of physical activity.
     
d.   My BMI classification was average or normal weight. I fall within the least risk of having associated illness since my BMI falls within the normal range. I feel that this is not an accurate classification since it simply classifies my bodyweight based on my height. It does not measure the percentage of body fat.
   
e.   My waist-to-hip ratio is 0.97. Based on WHR, I have very high risk of having illness associated with obesity. This classification is not too accurate for me because it considers the abdominal girth which is often where excess fat is stored. Although I do not have a very healthy diet and lifestyle, I still feel very healthy and that classification is a little too high for me.

2. Correlation was used to determine the relationship between bioelectrical impedance fat  and hydrostatic fat . The null hypothesis to be tested is that there is no significant relationship between bioelectrical impedance fat  and hydrostatic fat . The correlation analysis was conducted at 0.05 significance level. The decision is to reject the null hypothesis when the p-value of the correlation is less than 0.05 significance level. Otherwise, fail to reject the null hypothesis. After conducting Pearson correlation analysis, it has been found out that the Pearson correlation coefficient is equal to 0.79 with a p0.05. The correlation coefficient means that there is a strong increasing relationship between bioelectrical impedance fat  and hydrostatic fat . Since the p-value of the Pearson correlation coefficient is less than the significance level of 0.05, the null hypothesis is rejected. Thus, we are 95 confident that there is a significant relationship between bioelectrical impedance fat  and hydrostatic fat .

III. Closing Paragraph
After completing the lab, I have learned many things regarding my body. Specifically, I have learned to compute for body fat percentages using different methods. In addition to the body fat percentage, I also learned the risks associated to different body measures like waist to hip ratio. Overall, the lab taught me a lot about being conscious about my body with the help of bodyweight, body measurements and body fat percentages.

IV. Data
Calculations
HeightWeight
Weight kg  pounds2.204
 1802.204
 81.6696 or 81.67
Weight 81.67 kilograms
Height m  inches x 0.0254
 72 x 0.0254
 1.8288 or 1.83
Height 1.83 meters
Frame size
Elbow breadth  8 cm  2.54 cminch
 3.149 or 3.15 inches
Frame size (HeightElbow breadth) Large frame
Recommended weight range   164-188 lbs
Body weight classification weight is 180 lbs which is between 164-188 lbs
HeightWeight Classification Desirable
BMI (kgm2)  (weight in lbs x 703)  height in inches2   (180 x 703)  72   24.41
BMI Classification Normal range
BMI Associated Risk of Illness Average Risk
Girth  Fat  Constant A  Constant B   Constant C   10.2
         44.41  43.30 - 48.87   10.2  28.64  body fat
WHR  Waist girth Hip girth  34  35  0.97
Disease risk Very high risk
Sum of Skin Folds (SF)  chest  abdomen  thigh  25  32  24  81
Db  1.10938   (0.0008267 x SF)  (0.0000016 x SF)2   (0.0002574 x age)
Db  1.10938   (0.0008267 x 81)  (0.0000016 x 81) 2   (0.0002574 x 20)
Db  1.10938   0.0669627  0.0000000168   0.005148  1.037 or 1.04
Siri Equation  Body Fat  495 Db  450
       4951.04  450  25.96  Body Fat
FM  total body weight x fat  180 x 25.96
 46.728 or 46.73 lbs
FFM  total body weight  fat mass  180 lbs  46.73 lbs
133.272 or 133.27 lbs
Ideal  Fat 14.9
Ideal bodyweight FFM(1-ideal  fat)  133.27 lbs(1  0.149)
133.27 lbs(0.851)
156.603 or 156.6 lbs
Bioelectrical Impedance  16.5 percent fat
Hydrostatic Weighing
RV  0.24 x VC
 0.24 x (4.1)
 0.984
Dw  0.9937 gml
VGI  0.1 L
BMw  best underwater weight  tare weight  5.1 kg  3.6 kg  1.5 kg
Density (Db)   EMBED Equation.3  
 EMBED Equation.3  
Density (Db)  1.013507 or 1.01 gL
Body fat  (495Db)  450
(4951.01)  450
490.099  450
40.09901 or 40.1
Table 1

Pearson Correlation Results
Bioelectrical Impedence Fat Hydrostatic Fat Bioelectrical Impedence Fat  1.000 Hydrostatic Fat  .790  1.000  .344 critical value .05 (two-tail) .442 critical value .01 (two-tail)

Figure 1. Scatterplot of BEI and Hydrostatic Fat .
Body Composition Data Sheet

SubjectAge 20Gender MaleHeight (in) 72Height (m) 1.83Frame Size Large FrameWeight (lbs) 180Weight (kg)
81.67Recommended Wt Range (lbs) 164-188BMI 24.41HeightWeight Classification Desirable

BMI Classification Normal range

BMI Associated Risk of Illness Average risk

Girth MeasurementsSite A Right upper armSite B AbdomenSite C Right forearmSite A (in) 12Site B (in) 33Site C (in) 9Constant A (in) 44.41Constant B (in) 43.30Constant C (in) 48.87Fat 28.64
WHRAbdomen (in) 34Hip (in) 35Ratio 0.97Disease Risk Very high risk
SkinfoldsMENChest (mm) 25Abdomen (mm) 32Thigh (mm) 24Sum (mm) 81 WOMENTriceps (mm)Thigh (mm)Suprailium (mm)Sum (mm)Fat 25.96FM (lbs) 46.73FFM (lbs) 133.27Ideal fat 14.9Ideal body wt (lbs) 156.6
Hydrostatic  fatBioelectrical Imp  fat40.116.5